Vol. Pittcon Abstracts (1991)Different forms of metals and metalloids have varying degrees oftoxicity in biological systems. Becauseofthis, therehasbeenanincreasein the researchfocusedonthe

Journal of Automatic Chemistry, Vol. 13, No. 2 (March-April 1991), pp. 59-79

Pittcon Abstracts (1991)

Speciation studies of selenium and arsenic byreversed-phase high-performance liquid chroma-tography, employing hydride generation and induc-tively coupled plasma mass spectrometric detection

W. Charles Story, E. Hywel Evans, Douglas T. Heitkemper andJoseph A. Caruso (Department of Chemistry, University ofCincinnati, Mail Loc. 172, Cincinnati, OH 45221-0172;National Forensic Chemistry Center, U.S. Food and DrugAdministration, 1141 Central Parkway, Cincinnati, OH 45202)

Different forms of metals and metalloids have varyingdegrees of toxicity in biological systems. Because of this,there has been an increase in the research focused on thespeciation of metals at trace levels. Plasma mass spec-trometric detection of hydride species has been estab-lished as a viable technique for the determination of thesespecies at trace levels. One problem with the determi-nation of arsenic by plasma mass spectrometry is thepossibility of interference from the formation of ArC1+.Since many naturally occurring samples contain chloride,direct nebulization of the sample will introduce chlorideto the plasma. A possible solution to this problem is theuse of hydride generation to convert the arsenic to avolatile form coupled with separation from the chlorideusing a membrane gas liquid separator of the type usedpreviously.

The effectiveness of using hydride generation and themembrane separator in reducing the ArC1+ interferenceon the detection of arsenic was presented. A high-performance liquid chromatographic separation ofseveral arsenic and selenium species demonstrate thesimultaneous detection and speciation of these twoelements using hydride generation to increase the sensi-tivity. Figures of merit were discussed, along with thepertinent experimental details.

Addition of molecular gases to Ar gas flow for thereduction of polyatomic ion interferences on arsenicand selenium in inductively coupled plasma massspectrometry

Jiansheng Wang, E. Hywel Evans and Joseph A. Caruso(Department of Chemistry, M. L. 172, University of Cincinnati,OH 45221)

Due to its sensitivity and multi-element capability,Inductively Coupled Plasma Mass Spectrometry (ICP-MS) has developed into a very powerful technique for thedetermination of trace elements. However, the choice ofhydrochloric acid for sample dissolution, or a highconcentration of chloride in sample, makes it almostimpossible to determine arsenic or selenium because ofinterferences caused by 75ArCl+ on 75As+, 76ArAr+ on76Se+, 77ArCl+ on 77Se+ and 78ArAr+ on 78Se.

Different methods, such as co-precipitation of chlorides,chromatographic de-salting, alternative sample prep-aration procedures and addition ofmolecular gases to thecentral channel Ar gas flow have been used to overcomethese polyatomic interferences.

In this study, the effects of addition of molecular gasessuch as nitrogen to the central channel, the coolant andthe auxiliary flows have been investigated. A standardreference material and real fusion samples containing ahigh concentration ofHCL have been studied. The effectsof the addition of molecular gases to Ar flows onpolyatomic arsenic and selenium were shown.

Vapour generation techniques to measure arsenic byatomic fluorescence

P. B. Stockwell (P. S. Analytical Ltd, B4 Chaucer BusinessPark, Kemsing, Sevenoaks, Kent TN15 6QY, UK; L. C. Ebdonand Warren Corns, Polytechnic South West, Drake Circus,Plymouth PL4 8AA, UK); and K. C. Thompson (YorkshireWater Enterprises Ltd, Charlotte Road, Sheffield $2 4EQ, UK)Vapour generation techniques have proved immenselyvaluable when measuring environmentally importantelements at the levels present by existing techniques.Sensitivity improvements of500 times are not uncommonfor such measurements when linked to AtomicAbsorption and Inductively Coupled PlasmaSpectroscopy. Recently Stockwell et al. have describedadditional benefits of coupling such simple preparativetechniques to atomic fluoresence. A specific systemdesigned for mercury analysis provides simple instrumen-tal systems which can measure reliably down to few partsper trillion.

The determination of arsenic by hydride generationatomic fluorescence spectrometry using both non-dispersive and dispersive systems is well established.However, to date, there is no commercially availableinstrumentation for this technique, this is largely due tothe lack of reliable high intensity sources.

The paper described the use of a boosted dischargehollow cathode lamp to excite arsenic atoms obtainedfrom various designs of atom cells. The relative advan-tages and disadvantages of using dispersive and non-dispersive systems will also be discussed.

Applications of environmental interest were describedwith validation using a wide range of certified referencematerials at different levels, a fully atomated system wasalso described in detail.

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Determination of tin using hydride AAS includingflow injection analysis (FIA) and trapping in agraphite furnace

Zhang Li, Susan Mclntosh, Glen Carnrick and Walter Slavin(The Perkin-Elmer Corporation, 761 Main Avenue, Norwalk,CT 06859-0237)The determination of tin at ultratrace levels is veryimportant because the metal has an important environ-mental role even at very low levels. There is littleinformation in the literature on the tin determination asthe hydride, although it has been reported as difficultbecause the hydride is reported to be unstable.

The hydride method provides the opportunity to measurevery low concentrations of Sn and, at the same time, toseparate the element from potential interferences. Thesimplicity and convenience of flow injection analysis(FIA) has been used to explore the parameters of the Sndetermination as the hydride.

Still greater concentration sensitivity was found bytrapping the Sn hydride in a warm graphite furnace, andthen atomizing the Sn using conventional STPF con-ditions for Sn. The characteristic mass for Sn in pg by thisprocedure was the same as when solutions containing Snwere analysed in the furnace but large volumes of samplecan be analysed. Interferences were small using furnacetrapping.

The detection limit was 7 ng/1 for a 10-ml sample,probably the best instrumental, non-laser, detection limitever reported for Sn. The analytical precision was 3 to 5%RSD at ng of Sn. Inter-element interferences wereinvestigated. The recommended method has beenapplied to the analysis of Steel, River Sediment andOrchard Leaves and Bovine Liver Standard ReferenceMaterials, SRM’s and this data was presented.

The rapid determination of traces of selenium andtellurium in copper electrolytes

John Bozic, R. L Ethier, J. M. Balleny (INCO Limited, CentralProcess Technology, Copper Cliff, Ontario, POM 1NO, Canada)INCO Limited is a major producer ofhigh quality coppercathodes, using both electrorefining and electrowinningprocesses at its Copper Cliff Copper Refinery.

For process control purposes, and to ensure productquality, the rapid determination of Se and Te levels incopper electrolytes down to sub parts-per-million levelsis very important. Traditional procedures have reliedupon separation of the analytes by distillation, co-precipitation, solvent extraction, etc. prior to spectro-photometric measurement. Such procedures are slow andlabour-intensive. The authors investigated the capabilityof a number of modern instrumental analysis techniquesto determine Se and Te in the difficult matrix containing,for example, 200 g/1H:SO4, 100 g/1Cu, and 10 g/1Ni, Co.

6O

Direct ICP-AES and DCP-AES procedures lacked suf-ficient sensitivity and suffered from major inter-elementinterferences. Flame AAS with deuterium arc back-ground correction was also insensitive.

Anodic stripping voltammetry was found to be impracti-cal due to interferences from organic additives present inthe electrolytes.

Electrothermal Zeeman AAS and polarized flameZeeman AAS were both found to be capable of providingprecise and accurate Se and Te analyses with minimalsample treatment. For routine analysis the latter pro-cedure is favoured.

Te is measured using an air-acetylene flame, while anargon-hydrogen-air flame is used for Se. Matrix matchedstandards are essential. Details of analytical proceduresand comparisons between methods were presented andapplications of polarized flame Zeeman AAS to otherdifficult matrices were outlined.

Determination of hydride-forming elements ’inmetals by flow injection atomic absorption spec-trometry with on-line matrix isolation

S. G. Offley and N. J. Seare (Department of Chemistry,University of Technology, Loughborough, LeicestershireLEll 3TU, UK); J. F. Tyson (Department of Chemistry,University ofMassachusetts, Amherst, MA 01003); and H.A.B.Kibble (Philips Scientific, York Street, Cambridge CB1 2PX,UK)

Although the determination of elements such as As andSe by the generation of the volatile hydride withsubsequent atomization in a tube furnace is a maturetechnique, there are a number of limitations to theprocedure. These arise principally from the nature of thematrix components. Determinations of trace elements intransition metals are particularly difficult due to theinvolvement of the matrix element in a competingreaction with the reductant (borohydride) and thesubsequent reaction of the determinands with the reac-tion products.

This work described the application of a continuous flowmanifold which removes the matrix element from theanalyte solution by retention on a cation exchangecolumn. The resulting solution flows through the loop ofaflow injection (FI) valve and a discrete volume is injectedinto a FI manifold in which it is merged with streams ofacid, borohydride and argon prior to separation of thevapor in a glass U-tube device. This novel flow injectionmanifold design allows independent optimization of thematrix isolation and hydride generation chemistries. Thevarious operations may be fully automated, includingthat of column regeneration.


Optimization of the FI manifold for the determination ofSe was carried out using an alternating variable method.Optimum sensitivity was determined to be dependent notonly on reagent concentration but also on the totalreagent flow rate in the manifold. Optimization ofsensitivity for interference tolerance for both copper andnickel was achieved through maximizing the total reagentflow rate (15 ml min-1). Reducing the injection volumewas observed to increase the interference tolerance.

The accurate analysis of two standard reference coppermaterials (BAM 361 and NIST 454) was carried outcontaining 30 and 479 mg kg-1 Se(IV) respectively.throughput of 17 h-1 was possible with column regen-eration after each sample (triplicate injections of eachsample). A characteristic concentration of 1"0 ppb wasachieved with an RSD of 1"5% (10 ppb, N 12).

The FI manifold has also been optimized for thedetermination of As(III). Performance was observed tobe significantly affected by the condition ofthe silica tube-in-flame atomizer. Conditioning procedures were investi-gated. Investigation was made into the interferencetolerance of the system for Ni, Cu, Co(II), Sn(II),Sb(III) and Se(IV). Incorporation of an in-line mem-brane filter was observed to eliminate interferencememory effects associated with high concentrations ofCuand Ni and improve the precision.

Determination of As, Sb, and Se with electrothermalvaporization into a helium microwave-inducedplasma

Jorge Alvarado andJon W. Carna.han (Department of Chemistry,Northern Illinois University, DeKalb, IL 60115)Electrothermal vaporization (ETV) has been shown to bean excellent method for the introduction of aqueoussamples into helium microwave-induced plasmas (He-MIP). In a comparison study of ETV and ultrasonicnebulization (USN), Wu and Carnahan have shown theETV to exhibit superior Cland Br detection limits by twoorders of magnitude. The authors have shown similarbehavior for the analysis of As, Sb, and Se.

For this study, the sample introduction system consists ofa carbon cup type electrothermal vaporizer coated withtantalum in a glass chamber. A secondary pyrex vaporrestriction device is used to enhance the efficiency ofsample transport to the plasma.

Detection limits obtained with ETV (15 btl sample) andUSN, respectively, were: SB, 0"008 mg/1 and 0"098 mg/1at 259"805nm; Se, 0"122 mg/1 and 13"2 mg/1 at203"985 nm; and As, 0"015 mg/1 and 0"750 mg/1 at234"984 nm. To obtain the best detection limits nickelnitrate and lead nitrate were used as matrix modifiers.

Linear responses of three orders of magnitude wereobtained for each element.

Simultaneous ICP-AES determination of As, Sb, andSe by hydride-generation sample introduction

L. 21. Prell, 21. D. Lindner, V. A. Letourneau, and D. E. Dobb(Lockheed Engineering and Sciences Company, 1050 E. FlamingoRd., Las Vegas, NV 89119), and T. A. Hinners (US EPA,Environmental Monitoring Systems Laboratory, 944 E. Harmon,Las Vegas, NV 89119)The multi-element capability of ICP-AES has not beenrealized for low level As, Sb, and Se determinations.Pneumatic nebulization alone does not provide enoughsensitivity for these elements. However, hydride-generation (HG) sample introduction greatly improvesICP-AES sensitivity for these elements. To optimize thissensitivity, Hg sample introduction requires conversionof analyte species to their most efficient hydride-formingoxidation states. Presently, HG techniques for As and Sbrequire the addition ofKI to form the + 3 oxidation state.However, KI reduces Se to its elemental form, which doesnot form hydrides. Selenium’s most efficient hydride-forming oxidation state is +4, which is attained by highconcentrations (20%) of HCL. Since the conditions forHG differ between Se and the As/Sb pair, analyses ofthese elements were historically performed separately.However, there is no need to separate the analyses oncethe hydrides are formed. Thus, a continuous-flow hydridegenerator, which splits the sample flow into two reactionstreams, was used for simultaneous determination of allthree elements. One reaction stream (3"0 ml/min) washeated to 70 C and mixed directly with 0"28 ml/min of0" 1% NaBH4. This allowed the selenium hydride to form.The other reaction stream (3"0 ml/min) was heated to70 C and mixed with 0"42 ml/min of 1% KI before it wasmixed with 0"28 ml/min of 0"1% NaBH4. This allowedthe As and Sb to form hydrides. The streams were thencombined and introduced into a Hildebrand-grid nebu-lizer and water-jacketed Scott Spray chamber chilled toC. This combination served as a highly efficient gas-

liquid separator. The argon carrier gas pressure was 10psi (100 ml/min), which was too low to cause nebuliz-ation of the aqueous phase that is laden with salts. Withthe Hildebrand-grid nebulizer, a significant mist is notobserved unless the pressure is greater than 40 psi. Theanalytical figures of merit were evaluated using an ARL3560 mini-torch ICP-AES with synthetic solutions anddigests of NIST Fly Ash and NIST River Sediment. Therelative standard deviation was 1"5% for As and Sb, and5% for Se. The detection limits (DLs) were 0"8 tg/1 for Asand Sb and 5 btg/1 for Se. The Se DL was not affected bythe compromise HG conditions used for the otheranalytes. The linear range extended to 100 tg/1 for allthree elements. Above the 100 btg/1 level, pneumaticnebulization provides sufficient sensitivity. The devel-oped analytical procedure is a candidate method forapproval by the US EPA.

Notice: Although the research described in this articlehad been supported by the United States Environmental

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Protection Agency, it has not been subject to Agencyreview and therefore does not necessarily reflect the viewof the Agency and no official endorsement should beinferred. Mention oftrade names or commercial productsdoes not constitute endorsement or recommendation foruse.

A practical approach to automated ultra-low levelmercury determinations

Doug Shrader and Johnathan Moffett (Varian OpticalSpectroscopy Instruments, 201 Hansen Court, Suite 108, WoodDale, IL 60191)A continuous flow cold vapor generator (VGA-76) is.capable of routine detection limits of 0"2 btg/1 by atomicabsorption. Increasingly, legislation around the world isspecifying mercury levels to be measured at sub-ppblevels. European regulations require measurements to bemade at 0"05 btg/1. This implies that a system should beable to measure to an order of magnitude lower than0.2 btg.

For a number of reasons, atomic absorption is the logicalchoice to measure at these ultra-low levels. These includeits excellent sensitivity, adaptation to routine measure-ment and cost-effectiveness.

The ease with which gold can form an amalgam withmercury suggests a method to improve sensitivity. A goldcollecting surface can be inserted into the mercury vaporflow. After a suitable collection time, the adsorbedmercury can be quickly released by electrical heating ofthe gold collector. This gives an enhanced transientmercury signal. This study shows that the enhancementis directly proportional to collection time. Calibrationcurves are linear up to a mass of mercury equivalent to100 ng and absorbances of about 1"0.

In routine accurate measurements of sub-ppb levels ofmercury, several analytical challenges present them-selves. For instance, reagent contamination alone isfrequently greater than 0"05 btg/1. Technical problemsand their resolution were discussed. These includeminimization ofextraneous mercury being trapped on thecollector, interaction with an automatic sampler andvarious atomization cell designs.

The determination of tin in complex environmentalsamples by hydride generation atomic absorptionspectroscopy

Cindy Beach and Doug Shrader (Varian Optical SpectroscopyInstruments, 201 Hansen Court, Wood Dale, IL 60191)

Hydride generation AA techniques are used routinely forthe determination of As, Se, and Sb in environmentalsamples. Advantages include high sensitivity, simplicity,and relative freedom from interferences. Tin can also bedetermined by hydride generation, however, current

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methodology suffiers from severe difficulties. Theseinclude pH dependency, potential contamination prob-lems poor standard stability, and severe metalinterferences.

This paper described the development of a relativelysimple tin hydride generation AA method that eliminatesthese problems. In this study difficult environmentalsample were analysed for tin by continuous flow hydridegeneration. Continuous flow designs greatly reduceanalysis time as well as improve precision and allow forautomation. Various masking or complexing agents havebeen found to be extremely beneficial, not only in theelimination of metal interferences as reported by others,but also in significant improvements in sensitivity,precision and stability. A surprising aspect of the methodwas little pH dependency. Standards and samplescontained 1% HNO3 at a pH of


executed via programmable logic controllers on thefactory floor.

Automated flow-through microwave digestion foron-line sample preparation and inductively coupledplasma spectrometry

Ramon M. Barnes and Laura J. Martines (University ofMassachusetts, Department of Chemistry, Lederle GRC Towers,Amherst, MA 01003-0035)Innovative sample preparation for accurate elementaldeterminations, especially with inductively coupledplasma spectrometry, has been stimulated by the avail-ability of commercial microwave digestion devices thatprovide benefits compared to conventional open beaker,hot plate digestions. Closed and open vessel microwaveoven digestions are effective techniques that improveprecision and accuracy, reduce contamination, andincrease sample throughput. One practical limitationresults from the sealing of closed vessels and the insertionof vessels into the microwave oven. The combination ofmicrowave digestion and flow techniques was firstreported by Burguera et al., and has subsequently beeninvestigated by others. Continuous or stopped-flowonline microwave digestion can increase sample through-put and extend sample handling automation.

A commercial laboratory microwave oven is available(Prolabo A300) with the capability to perform automateddigestions by utilizing microprocessor control and amechanical arm. The microwave energy in this oven isfocused in a small cavity. In one approach to combinemicrowave digestion with sample flow techniques, thesample tubing is placed in the digestion cavity. As thesample and acid are pumped through the tubing insidethe cavity, the microwave energy can heat the acid andcontrolled sample digestion can occur.

Several experimental considerations must be made forthe practical development of this approach. The acidstype and volume, use offlowing streams and stopped flowtechniques, settling of solids from the reaction solution,control ofreaction pressure, and formation ofgas bubblesare some of these considerations. These effects and theanalytical characteristics of flow-through microwavedigestion techniques will be described. An expert systemthat helps to select the digestion parameters can beinterfaced with the flow-through system to enhanceautomation of the digestion methods development.

Sample preparation of oxide materials using thepulverizing, pelletizing and fusion method underroutine conditions in fully automatic systems

G. Hawickhorst (HERZOG Maschinenfabrik GmbH, P. O. Box2329, D-4500 Osnabriick, Germany)Almost 15 years ago the first installations of fullyautomatic sample preparation systems based on pulveriz-ing and pelletizing had been established in the cement

industry. The first systems based on the fusion techniquehave been installed during the last few years.

With improved speed, performance and reliability of thethird generation of those systems, entry was made in steelplant-, mining- and other laboratories.

The advances in electronics and robotics gave thenecessary tools to automate the fusion process. Thisprocess is much more sensitive to trouble-causing effectssuch as dust, vibration etc. than the pulverizing andpelletizing process.

The fused bead eliminates several negative effects in thesample (mineralogical, particle size, etc.), but on theother hand there is the danger ofcracking ofthe glass diskdue to internal stress.

Beside the analytical requirements these facts also have tobe taken ito account when deciding which method to usefor fully automatic on-line systems under routine con-ditions for process control.

With both systems there is enough experience available tojudge in which field of application which system willpromise the best success concerning analytical results,speed, lowest maintainance cost, and reliability.

Layouts of existing installations were shown and thelatest experiences with installations in various industrieswere reported.

The adaptation of FIA for the determination ofphosphate in phosphate ore

Franklin E. Patrick and John E. Gibson (IMC FertilizerIncorporated, P.O. Box 876, Bartow, FL 33830)IMC Fertilizer is the world’s largest private producer ofphosphate rock. As such, the capability for rapid andaccurate determinations ofphosphate in phosphatic ore iscrucial. In the authors’ lab, the following criteria havebeen designated as necessary to provide this capability:

(1) Throughput of at least 60 samples/hour.(2) A range from 10 to 1500 mg P205/1.(3) Relative standard deviation of less than 0"5% at

the upper end of the range.

These criteria reduced the number of possible analysersto a select few. The Tecator 5010 FIA Analyzer wasevaluated and was found acceptable.

The Tecator 5010 Analyzer is an automated flowinjection instrument interfaced with a personal computerusing the manufacturer provided software, SuperFlow II.The standard molybdo-vanadate procedure as describedin the AOAC Officiall Methods of Analysis was adapted tothe instrument. This paper reported on the manifoldconfiguration, flow rates, and other considerations

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necessary to run this method on the analyser and meet thestringent analytical requirements. Calibration is accom-plished by analysing phosphate rock standards coveringthe range encountered in digested rock samples. Datafrom these standards are processed using a polynomialcurve fitting routine to obtain a calibration curve thataccurately fits the non-linear absorbance versus concent-ration relationship.

Data from the Tecator Analyzer compared favorablywith data from three different instruments: an air-segmented continuous flow analyser, a discrete volumeautomated batch analyser, and an ICP. The throughputof the system is 90 samples/hour. A standard deviation of4.0 mg P205/1 was established for samples at the higherend of the cencentration range.

The module design of the analyser was also an importantconsideration. There are currently three analysers at twoseparate locations and there are plans to add another oneat a third location. The flexibility offered by the designallows components to be swapped if needed to reducedown time.

A practical system approach to NIR industrialprocess analysis

Barry Read (Bran + Luebbe Analyzing Technologies, Inc, 103Fairview Park Drive, Elmsford, NY 10523)Successful implementation of spectroscopic analysis inthe process control environment requires knowledge ofthe physical and chemical properties of the constituent tobe analysed, as well as its corresponding matrix.

In addition to the fundamental spectrochemistry, theproper sensor must be selected for the application toensure accurate and reliable data collection. Next,sample handling techniques must be optimized for thesensor and the individual process environment.

Once these factors have been solved, data acquisition,process equipment interface and integration of theexisting automation processes is required before thesystem can be truly considered as an in-line sensor.

The implementation strategy used in placing nearinfrared sensors into the process environment werediscussed with some real world examples of theseprojects.

Flexible sample and data handling systems for thedetermination of total nitrogen sulphur

John S. Crnko, Dewey Smith and Mike Martin (AntekInstruments, Inc. 300 Bammel Westfield Rd., Houston, TX77090)Sampling and analytical techniques for the new totalnitrogen and total sulphur analyser were presented.Descriptions of the various equipment used to eliminate

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or minimize sample preparation for many differentsample types were included. New data handling systemswith customized software are utilized in a stand aloneintegration system, a personal computer or as an on-board function of the Antek Analyzers. All of thesesystems can be used in both manual and autosamplermodes.

The ability to analyse solids, liquids, and gases by using asingle pyrotube configuration is highlighted. Also a newmore efficient inlet oven for solid materials will bedescribed.

Data generated using a new autosampler for solidsmaterials and a new gas sample injection system areincluded.

Examples of operational characteristics are illustrated toshow peak integration flexibility, data archival, reportformats, quality assurance measures and ease of use.

All system descriptions are accompanied by applicationdata including measurement at ppb levels for bothnitrogen and sulphur. Materials analysed include bothorganic and inorganic matrices such as petroleumproducts, polyolefins, petrochemicals, and agricuturalproducts.

The use of automated gravimetric techniques forenhanced analytical precision

Brian G. Lightbody and Sally D. Dowling @mark Corporation,Hopkinton, MA 0178)The use of automated equipment for routine samplepreparation is growing, however, it is important tomaintain a high level of control to maintain assayprecision. Recent developments in automated works-tations have resulted in capability to use an on-board 4-place analytical balance to monitor the progress of thesample prep process. This paper discussed severaltechniques built into the automated instrumentationwhich use analytical balance results to help ensure theprecision and integrity of the analytical process. Someexamples are as follows:

(1) The use ofconcentrate weight to calculate and adda diluent during automated dilutions.

(2) The use of sample weight to calculate and add aproportional amount of solvent.

() The use of sample weight to calculate and add aproportional amount of internal standard.

(4) The monitoring of the weight of all reagentadditions to ensure adequate system performance.


Continuous monitoring of personal exposure

Eirik Nordheim and Helge Nes* (AluminiumindustriensMiljosekretariat, Sigurd Syrs gate 4, N-0273 Oslo 2, Norway;*Elkem Aluminium Mosjoen, P.O. Box 348, N-8651 Mosjoen,Norway)Industrial hygiene monitoring of personal exposure istraditionally carried out with sampling equipment likefilters, impinger or adsorbent tube connected to asampling pump or alternatively spot sample with hand-held adsorbent tubes. The latter type gives a crudeestimate of short-time exposure while the first type givesan average exposure over the time period measured. Inaddition the result of the measurement is quite often notavailable for some time due to time-consuming labora-tory analysis. For some specific applications directreading instruments or dosimeters are now available, butmost of them do still have a fairly limited application dueto lack of continuous recording capacity.

Recently, lightweight dataloggers which are batteryoperated and with large datastorage capacity havestarted appearing on the market. These are flexibleinstruments with several input ports and capable ofrecording signals from a wide variety of sensors.

In the Norwegian aluminium industry the authors haveover the last years tested out the use of a specificdatalogger with 42 K storage capacity and 16 channels.This has been used together with sensors for CO, SO2,respirable dust, static magnetic fields, body vibration,body temperature, pulse, skin temperature etc.

For most of these factors recordings have been made atone second intervals over an 8-hour shift period, giving acontinuous record of exposure during a work period. Thedatalogger will thus give information about averageexposure over a selected time period and, since time isalso recorded continuously, be able to show short-timehigh exposure peaks with exact time when these occurred.For the purpose of health related monitoring these areoften of more interest than the 8-hour average exposure.

The datalogger is connected to a PC after use for transferof data, complete printout and graphical presentation.This can be done immediately after the measurement isfinished. The operator who has carried the equipment,may be given a graph showing his exposure that daywhile he is still at work.

This lecture gave a complete description to the equip-ment, together with examples from actual monitoring inaluminium smelters, and also discussed the advantages ofthis type of monitoring in relation to employee health.

Laboratory automation occurring at municipalwastewater treatment plants

Gregory A. Zelinka (Madison Metropolitan Sewerage District,1610 Moorland Road, Madison, WI 53713)Because of operational, liability, or permit requirements,today’s municipal wastewater treatment plants arerequired to analyse a variety of sample matrices for a

complex set ofchemical and biological parameters. Thesematrices include: soil, plant tissue, ground water, surfacewater, and industrial wastes, as well as the moretraditional municipal wastewater and sludges. Thechemical parameters involve nutrients, metals, andorganics, many existing at concentrations equal to orbelow current method detection limits. To meet thesenew and changing demands as well as keep up with theever increasing sample load, it had become necessry forwastewater treatment plants to automate as much of theroutine chemistry as possible. This paper discussed one ofthe ways Madison Metropolitan Sewerage District hasattempted to automate its analytical workload.

One of the major areas intially examined was automatingour solids and nitrogen procedures. Measurements forsolids have been enhanced by coupling an electronicbalance to a PC-based spreadsheet. This has reduced thetedium of recording weighings by hand, sped-up thecalculations, and minimized the data handling errors.Nitrogen (NH3 & TKN) analyses have been automatedby switching analytical methods from a Macro Kjeldahlmethod to a Semi-Automated method utilizing anAutoanalyzer. This has not only saved analytical time,but also energy and reagents as well.

A second area examined was the addition ofautosamplersand timers to two of GCs, an IC, and an AA. Thisaddition has allowed these instruments to operateunattended beyond regular working hours or over theweekend.

Data acquisition is being accomplished by dedicated PCsdistributed throughout the lab and through the use ofstandardized data acquisition software. The authors arecurrently able to track the analog output from AAs,Autoanalyzer, IC, and GCs with a single vendor’ssoftware.

Data quantitation utilizes a series ofspecialized programswritten in a compiled basic, which meets specificquantitation requirements and allows for custom reportgeneration.

Quality assurance data is either automatically extractedand calculated (from the custom report format) or amanually entered into a daily QA report which flagscontrol limit exceedances and facilitates monthly andquarterly report summaries.

An automated, small-volume, block-digester pro-cedure for the high-speed, simultaneous determi-nation of total Kjeldahl nitrogen and total phosphor-us in water samples

Charles J. Patton (U.S. Geological Survey, National WaterQuality Laboratory, 5293 Ward Road, Arvada, CO 80002)About 20 000 surface and ground water samples areanalysed for total Kjeldahl nitrogen (TKN) and totalphosphorus (TP) at the US Geological Survey National

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Water Quality Laboratory (NWQL) each year. Recentestimates indicating that sample loads for TKN and TPwill double by 1993 have spurred efforts to streamline allsteps of these lengthy and labor intensive tests.Significant improvement in processing rates for pre- andpost-digestion sample preparation, sample digestion, anddetermination of ammonium and orthophosphate ions indiluted digests have been achieved for these determi-nations relative to current NWQL procedures.

The NWQL currently uses two different digestionprocedures- a Kjeldahl, block digestion proceduresimilar to US Environmental Protection Agency (EPA)method 351.2, and an acid/persulfate, autoclave diges-tion procedure, similar to EPA method 365.1 for TKNand TP determinations, respectively. By determining TPin TKN digests, as per EPA method 365.4, samplepreparation time is halved. Time required for thedigestion step was reduced from four hours to one byhalving sample and reagent volumes as per Jirka et al.Using syringe pump-based dispenser/diluter modules toautomate pre- and post-digestion sample preparationpermits these operations to be performed at rates ofabout100 samples hr-1, which is comparable to the rates atwhich ammonium and orthophosphate ions in dilutedTKN and TP digests can be determined using third-generation continuous flow analysers.

In addition to increased production capacity, benefitsafforded by this approach include decreased exposure ofanalysts to caustic and toxic materials, lower reagent andreagent preparation costs, and lower costs associatedwith proper disposal of caustic and toxic wastes resultingfrom these tests.

Selecting a continuous flow analyser for the analysisof sludge and industrial waste effluents

Shirley Arment and R. B. Roy (ALPKEM Corporation, 14625S.E. 82nd Drive, Clackamas, OR 97015)

Both air segmented (e.g. AAII and RFA) and nonseg-mented (FIA) continuous flow analysers are available forthe analysis of sludges and industrial waste effluents. Inrecent years the originally introduced CFA Technology,such as that of the AAII, have undergone muchimprovement both in mechanical designs and incorpora-tion of computer capabilities.

For instance, the RFA (Rapid Flow Analysis) system wasdevloped to use glassware with reduced internal diam-eter, electronic timing of the segmentation gas, peckingsampler and ’gated’ detector which needs no debubblingof air in the flowcell. Thus, the system provides fasterthroughput and low consumption of reagents, which inturn, reduced the cost of reagent and waste disposal.

FIA (Flow Injection Analysis) systems have similarfeatures as the RFA except the FIA does not require airbubbles to separate samples. Both RFA and FIA haveimproved analytical performances in comparison to AAII

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systems. Unlike AAII systems, attainment of a steadystate to analyse sample is not required in both RFA andFIA systems. Sample analysis rates well over 100 samplesper hour are easily achieved.

The advantages and limitations of continuous flowanalytical systems which are currently used in municipalarid industrial laboratories were presented. In addition,performance data which will review design aspects ofALPKEM RFA systems, and, show applications demon-strating their various capabilities for environmentalanalysis were discussed.

Ammonia and total Kjeldahl nitrogen determi-nations using fast distillations and gas diffusion

Bernard Bubnis (Novatek, 10 West Rose Avenue, Oxford,OH 45056), andJurgen Moller (Tecator AB, Hoganas, Sweden)Automated procedures for measuring ammonia and totalKjeldahl nitrogen (TKN) have been comparativelytested against a currently accepted EPA method.

Three test procedures for measuring ammonia and TKNhave undergone the Alternate Test Procedure (ATP)outlined in the protocol of 20 June 1990. The methodsare: automated steam distillation followed .bYNesslerization, automated steam distillation with titri-metric detection and the automated Flow InjectionAnalysis (FIA) gas diffusion procedure. All TKN meth-ods used aluminium block digestion for samplepre-treatment.

Final effluent samples obtained from ten sites represent-ing the top five SIC classifications for each parameterwere tested by each of the three methods. Data indicatethat fast steam distillation gives results which areaccurate and more precise than the accepted method.Further, the steam distillation process proved to be lesstime consuming and easier to operate even whencompared to the ammonia electrode method.

The FIA gas diffusion procedure also showed improvedresults in addition to having an ammonia methoddetection limit (MDL) of 0.01 mg/1. The automated FIAmethod was straight forward and uncomplicated givingresults in 70 seconds.

Data for each of the procedures were presented. Themethod approval process was discussed and outlined inrelation to the submitted ammonia and TKNmethodologies.

Automated inorganic ion analyses for wastewater,sludge and stack gas incineration

Aldo Conetta (Bran + Luebbe Analyzing Technologies, Inc., 103Fairview Park Drive, Elmsford, NY 10523-1500)Both Federal and State EPA Agencies are mandatingincreased analytical testing for inorganic analytes.Knowing the level of contamination will often dictate the


best remedial action required for cleanup. The end resultis to significantly reduce contamination to the nation’swaterways, soils and air for a healthier environment.

There is no sample matrix that is immune from thesemandates, and, as each year passes, the number oforganic and inorganic analytes being added to thehazardous waste list is increasing. For example, the USEPA Contact Laboratory Program has realized anapproximately 500-fold increase in analytical testing inthe past decade. In addition, there are approximately3000 private laboratories involved in all aspects ofenvironmental testing.

Automation for the environmental laboratory throughinstrumentation is the only alternative to meet analyticaldemands and still maintain a favorable cost/benefit ratio.Placements of such instrumentation have exceeded onebillion dollars per year worldwide.

Analytical instrumentation- Analytical instrumentation canbe categorized in many ways. However, with respect toenvironmental analyses a logical approach would be asfollows:

Laboratory analysers

On-line process analyser

Stack gas analysers

The one common thread for each of these analysers isautomation. A review of analytical instrumentationcurrently available, coupled with specific applicationswas presented.

Fast automated multi-element elemental analysis ofsludges and effluents using a new sequential atomicabsorption spectrometer

William Batie and A. E. Bernhard (Analyte Corp., 910 ChevyWay, Medford, OR 97504)Over the past 10 years there has been a barrage ofpublications and papers extolling the desirability ofmethods alternative to Atomic Absorption Spectrometry(AAS) for the analysis of metals in sludge and effluents.Despite this, and the advantage of being essentially asingle element technique, AAS continues to be widelyused for this application because of its simplicity ofoperation and relative freedom from interferences com-pared to emission techniques.

Attempts have been made to automate AA resulting inthe capabilities of analysing up to eight elements in anumber of samples, one element at a time. This meansthat the analysis of the first sample of a group of samplesis not complete until the last sample has been analysed.In addition, 8 elements are insufficient for this appli-cation, requiring operator intervention to change HCLs.

A new AA spectrometer, the ANALYTE 16, providesfully automatic analysis of up to 24 elements in a single

pass on a sample at the rate of 10 elements per minute.This is achieved through use ofa 16 hollow cathode lamp(HCL) turret which selects elements, one at a time, with aspeed of second. During the time the carousel isselecting a new HCL, the grating drives to the properwavelength and the bandwidth is changed appropriately.

This novel instrument, and its use and capabilities for fastautomated analysis of sludges and effluents, werediscussed.

Automated air analysis of volatile organic com-pounds on a new intermediate polar phase

R. P. M. Dooper, D. Zwiep (Chrompack Inc., 1130 Route 202,Raritan, NJ 08869); and H.J. Th. Bloemen (National InstituteofPublic Health and Environmental Protection, P. O. Box 1, 3720BA Bilthoven, The Netherlands)In recent years interest in air analysis has grown rapidly,especially for such volatile organics as ozone precursors.Automation of these analyses, usually done by capillarygas chromatography, is possible nowadays. To improvethe reliability of these analyses, identification of thecompounds of interest on two columns with differentstationary phases often used. The most commonly usedstationary phase is a 100% polymethyl silicone phase.

The best choice of a second column is one with a polaritybetween 5% phenyl/95% methyl silicone and an OV-17type of phase.

This new phase has been developed. The phase is highlyinert and chemically bonded. Also, the phase is especiallyuseful in ECD applications.

Automation of the USEPA’s contract laboratoryprogram requirements of the determination of 15elements in a variety of environmental samples byinductively coupled Plasma Optical EmissionSpectrometry (ICP-OES)

Geoff Tyler, Flay Finotello and Tran Nham (Varian OpticalSpectroscopy Instruments, 201 Hansen Court, Suite 108, WoodDale, IL 60191)

The requirement for strict quality control and qualityassurance in the analysis ofenvironmental samples is nowwell established and fully documented by theEnvironmental Protection Agency (EPA) ContractLaboratory Program (CLP). This need to ensure thevalidity and security of analytical data has increased thenumber of quality control test solutions required to beanalysed.

This paper presented a Quality Control Protocol (QCP)software package designed for automation of sampleanalysis, QC testing, implementation of QC test failureactions and results reporting conforming to USEPA’s

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CLP requirements for ICP-OES. Comparison of detec-tion and interference data with EPA recommendationsshows that the package is applicable to a variety ofenvironmental samples including wastewaters, potablewaters, effluents and acid rain. Alternative elementalwavelengths providing higher analytical performance isrecommended. The screening of sulphur in environmen-tal samples ICP-OES was also proposed.

Analytical performance of an automatic samplepreparation system for atomic absorptionspectrophotometry

,James A. Gaunt (Department of Civil and ConstructionEngineering, 123 Town Engineering Building, Iowa StateUniversity, Ames, IA 50011)Preparation of samples for analysis by atomic absorptionspectrophotometry (AAS) frequently requires dilution,addition of matrix modifiers, and preparation of a rangeof calibration standards. Use of an automatic samplepreparation system (prep station) can significantlydecrease the time required for these activities.

The subject of this investigation was a PS-150 PrepStation used with an ISC-150 Intelligent SampleChanger and a TJA Smith-Hieftje 12 AA/AESpectrophotometer (all components supplied by ThermoJarrell Ash Corporation, 8 E. Forge Parkway, Franklin,MA 02038). Soon after the PS-150 Prep Station wasplaced in routine service, a quality assurance auditsuggested that a study of the analytical performance ofthe prep station would be appropriate.

The gross volumetric accuracy of the prep station wastested by weighing distilled water delivered into taredsample tubes using the following protocol: 2"0 ml sampleuptake (SU), 1"0 ml matrix modifier (MM), 5"0 ml finalvolume (FV). The average weight delivered was 4.9900 g(s 0"0131, RSD 0"263%, N 12).

The sample dilution and matrix modifier and matrixmodifier functions were tested by using known concen-trations of Cu++ as the ’sample’ or the ’matrix modifier’in several different protocols so that the preparedsolutions should have contained exactly 0"500 mg/1. Sixreplicates of each solution were prepared and subse-quently analysed using flame AAS. Recoveries of Cu++were between 99% adn 102% for dilution ratios of 2x,5 x, 10 x and 20 x. A matrix modifier dilution ratio of50x(SU=2.0, MM=0.1, FV 5.0 ml resulted in a recoveryof 108% (0"538 mg/1 Cu++).

The standard preparation function was tested by prepar-ing six replicate sets of standards for both Ca++ and

++Cu using the prep station and analysing them by flameAAS calibrated with manually prepared standards. Theresults were as follows:

Theo. mg/l Ca 2"00 4"00 6"00 8.00 10"00Mean 2"72 4"62 6’83 8’82 10"83

0"06 0"27 0"29 0"38 0"42Recovery (%) 136 116 114 110 108Dilution ratio 50x 25x 16"7x 12.5x 10x

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Theo. mg/1 Cu 0"200 0"400 0’600 0"800 1"000Mean 0"200 0"405 0"637 0’881

0"001 0’004 0’003 0"009 0"003Recovery (%) 100 101 106 110 103Dilution ratio 50x 25x 16"7x 12"5x 10x

The PS-150 Prep Station is a statisfactory instrument forpreparing samples for analysis by AAS provided that thedilution ratio of sample or matrix modifier is not greaterthan 20x (i.e., uptake 0"3 ml, final volume 6’0 ml).However, it does not appear to be a reliable instrumentfor preparing calibration standards.

Automatic continuous on-line analysis of haloformsin drinking water using process GC with electroncapture detection

Matthew Przybyciel (ES Industries, 8 S. Maple Avenue,Marlton, NJ 08053)Haloforms have been shown to be chlorination by-products of municipal water supplies. Possible haloformcontamination have raised concerns over drinking waterquality and has left to increased manual sampling foranalysis. Unfortunately, manual sampling may not occurat frequent enough intervals to detect problems. Inaddition, manual sampling is extremely labour intensiveand is prone to operator error.

The continuous automatic analysis ofwater using processGC with flame ionization detection has been commer-cially available for several years. The detection for manyhaloforms are in the 5-20 ppb range using this type ofinstrumentation. The levels are achieved using a con-tinuous sparging technique along with the process GC. Inorder to achieve lower levels ofdetection for the haloformsusing this type of instrumentation, electron capturedetection will be required. Historically, electron capturedetectors have not been stable or reliable enough for usein continuous automated instrumentation, however, theelectron capture detector used in this study has beenspecially adopted for use in continuous operation.

In this paper the continuous detection of the haloforms atlevels less than ppb was shown. In addition, long termstability, reproducibility, cycle time and reliability of theinstrumentation was discussed.

Automated pre- and post-column reaction/detectionsystems in column liquid chromatography andcapillary gas chromatography

H. Lingeman, U. A. Th. Brinkman and E. A. Hogendoorn2(Department of Analytical Chemistry, Free University, DeBoelelaan 1083, 1081 HV Amsterdam, The Netherlands;2National Institute of Public Health and EnvironmentalProtection, P.O. Box 1, 3720 BA Bilthoven, The Netherlands)In spite of the fact that column liquid chromatography(CLC) and capillary gas chromatography (CGC) are(becoming) mature analytical techniques, selectivity and


sensitivity are still not always sufficient when solutes inrelatively complex matrices (e.g. biological, environmen-tal, food and fodder) should be determined. One of thepossibilities to overcome this limitation is the use of achemical reaction/detection (derivatization) procedure.These reactions can be performed in several modes:before, during and after the separation and in an on-lineand off-line mode with CLC.

However, for routine analyses automation is one of thekey parameters, which means that on-line methods arepreferred over time-consuming and laborious off-lineprocedures.

Nowadays, a number of sample processors andcontinuous-flow systems are available allowing the auto-mation of pre- as well as post-column reaction/detectionand sample preparation techniques.

In this presentation the automated pre-column phase-transfer catalysed dansylation of phenolic steroids inplasma using a Model 231-401 sample processor, theautomated on-line pre-column dialysis and concentra-tion of benzodiazepine containing samples using acontinuous-flow system (ASTED), the combination ofanon-line post-column derivatization and on-line pre-column dialysis procedure of the determination ofsulfonamides in food products, and a clean-up anddetection system for the determination ofpolar pesticidesin aqueous samples using automated (ASPEC) ion-pairderivatization with pentafluorbenzylbromide and capill-ary gas chromatography with electrochemical detectionwas discussed.

Analytical variables (e.g. reproducibility, repeatability,throughput, detection limits) of the different methodswere compared.

On-line analysis of moving solids by transientinfrared spectroscopy

Roger Jones and John McClelland (Center for AdvancedTechnology Development and Ames Laboratory-USDOE, IowaState University, Ames, IA 50011)

Industry requires methods to quantitatively and non-destructively analyse solid materials in real time as theymove along a production line. Transient InfraredSpectroscopy (TIRS) can provide such analyses. InTIRS a thin layer of the sample material is transientlyheated or cooled, usually by a gas jet, as it passes throughthe field ofview of an infrared spectrometer. This surfacelayer is spectroscopically different from the bulk of thematerial, and it may be analysed separately from thebulk. If the layer is heated, it acts as a thin emissionsource with much less self-absorption than is characteris-tic of thick emission sources. If the layer is cooled, it actsas a thin absorption sample through which blackbodyemission from the bulk of the sample passes on its way tothe spectrometer. In both cases, the layer is thin enoughthat saturation is reduced sufficiently for quantitativeanalysis.

A protype industrial-site instrument is presently beingdeveloped for on-site test and demonstration. It is basedon a Bomem MB-100 FTIR spectrometer fitted withspecial sampling optics. A commercial hot-air tool with amodified nozzle is used as the surface-heating source. Theproperties and performance of the prototype werediscussed.

Laboratory results demonstrating some of the specialproperties of TIRS were also covered. TIRS can be donewith only moderately hot (below 100 C) or cold (above-50 C) gas jets, as long as the heating or cooling is rapidenough to create a suitably thin transient layer. Theperformance at various jet temperatures will be pre-sented. As the figure below demonstrates, the morpho-logy of non-isotropic materials can be determined byusing polarization-sensitive detection. Depth profilingcan be performed by controlling the thickness of thethermally altered layer at the time of observation. Thefreedom ofTIRS from interference effects (fringes) whenthe sample material is thin and has parallel sides was alsoshown.

Determination of vitamin C content in pharaceuti-cals via flow-injection chemiluminescence detection

John Vicars and Chu-Ngi Ho (Department of Chemistry, Box 23,350A, East Tennessee State University,Johnson City, TN37614)Because of the nutritive and other perceived health valueof vitamin C, commercial sources of the vitamin arenumerous and availability abundant. Because of itsimportance, many methods have been developed for thedetermination ofvitamin C in all sorts ofsamples rangingfrom pharmaceuticals, agricultural and food products tobiological fluids. The methods include classical titri-metry, ultra-violet and visible absorption, luminescencespectrometry and high performance liquid chromato-graphic separation.

The authors have developed and implemented a simpleand rapid flow injection system coupled with chemi-luminescence (CL) detection to analyse pharmaceuticalsamples for the amount of vitamin C present. The CLsystem utilized is that of peroxyoxalate employingbis(trichlorophenyl)peroxyoxalate (TCPO). The vitaminC in different samples is reacted with a given fixedamount ofhydrogen peroxide in the presence ofCu(II) ascatalyst. Imidazole which catalyses the CL reaction isadded to the solution. The excess hydrogen peroxide canthen react with TCPO to produce the CL using peryleneas fluorophore. The TCPO and perylene are premixedand pumped into a flow system. The vitamin C andexcess hydrogen peroxide incubation mixture is injectedthrough a 20 btl Rheodyne injector loop into the flowstream. The reaction to produce CL takes place in theflow and the signal is detected in a homemade flow cellplaced in front of a photomultiplier tube. The TCPO andperylene are made in methylacetate while the reactionmixture is entirely aqueous. There does not seem to beany mixing problem at all. In this presentation, the

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procedure, optimization of the solvents used, flow rate,and concentration of different reagents, data and theresults obtained were discussed.

Extending the capabilities of flame atomic absorp-tion spectrometry with on-line sample treatment

S. R. Bysouth, J. F. Tyson, E. Debrah, T.J. Gluodenis andR. M. Larue (Department of Chemistry, University ofMassachusetts, Amherst, MA 01003)

Many of the limitations to the performance of flameatomic absorption spectrometry (FAAS) can beaccounted for by (a) shortcomings in the nebulization andatomization processes and (b) interference effects due tomatrix components. For a number of years, research inthe authors’ group has been directed towards overcomingthese limitations by the use of continuous-flow and flowinjection procedures ofsample handling. Three uses havebeen made of these techniques: (i) separation of theanalyte from its matrix, (ii) preconcentration of theanalyte and (iii) generation of volatile analyte species.Examples of recent work in each of these areas werepresented to illustrate the potential of on-line, sampletreatment procedures. The determination of trace ele-ments in silver as silver chloride with on-line filtrationprovides an example of the first procedure where thematrix is removed. The alternative version of this system,where the analyte is precipitated, was demonstrated forthe on-line preconcentration of copper as the hydroxideas an example of the second procedure. On-line gener-ation of a volatile metal complex where the complex issubsequently extracted into supercritical or liquid carbondioxide before direct introduction to the atomizerinvolves all three procedures. Vaporization of the carbondioxide carrier stream can be achieved using a simpleheated restrictor. This device has been shown to producecalibration curves with sensitivities comparable to thatobtained with continuous nebulization, when only 20of a solution of the complex in a solvent is injected.Results of the investigation of the separation of thecomplex from the aqueous phase by solid phase extrac-tion or precipitation followed by re-dissolution in carbondioxide and direct liquid-liquid extraction werepresented.

The extension of such procedures for use in conjunctionwith electrothermal atomization AAS were alsodiscussed.

Method studies in ambient air analyses

Dick Siscanaw (US EPA, Region 1 Laboratory, 60 Westview St.,Lexington, MA 02173); Hui Wang and Delon Maas (Roy F.Weston, Inc., Landmark One, 1 Van de Graaft Dr., Burlington,MA 01803)In environmental laboratories, most of the work hashistorically been water, soil, and drum samples. Now

7O

measurements for organic air toxics are increasinglybeing requested. The authors’ load has more thandoubled in the past three years. For air, the laboratoryfaces a variety of situations which have different dataquality objectives and require different methodologies.For example, an emergency is treated differently from anambient air study at a superfund site.

Five years ago, most of the authors’ air analyses were foremergencies and an occasional site investigation. Theportable gas chromatograph was used approximately90% of the time. The remaining techniques were theTedlar bags, color detector tubes, and NIOSH methods.These techniques are still used today. The practicalquantitation levels (PQLs) ranged from 10 ppb for thevolatile aromatics to ppm. This was relatively high forsome ambient site investigations.

In 1986, Region started measuring the volatile organicsusing the Spherocarb and Tenax solid adsorbents, EPAmethods T01 and T02. A measured volume of air isdrawn through the trap, typically 5-20 1, which is laterthermally desorbed into the gas chromatograph/massspectrometer (GC/MS). Our PQLs dropped by 50 ppt.Last year, the laboratory expanded its air program toinclude the SUMMA passivated canister, EPA methodT014. In this method, 500 ml is drawn into the GC/MS.for analysis. QLs for the canister is approximately2 ppb.

This presentation focused on experiences with thesemethods and the modifications made. The subjectsincluded are field analyses and screening, varioussamplers (sector sampler), quality control (replicates,back-up, and distributive samples), cleaning apparatus,and the preparation of our standards.

Automatic perimeter monitoring ofairborne organiccompounds at a superfund remediation site utilizinga gas chromatograph equipped with a multipointsampling system

Amos Linenberg (Sentex Sensing Technology Inc., 553 BroadAvenue, Ridgefield, NJ 07657)Since the US National Priority list for the clean-up of thenation’s most highly contaminated sites has been created,EPA has established funding priorities and made theadvancement of sites to the construction phase a maingoal of the EPA Superfund Program.

Many of thse sites are located near residential areas,therefore, it is necessary to determine the identity andquantity of the pollutants that escape the confines of theremediation site. Usually, this is accomplished byobtaining samples at various locations along the peri-meter of the site and transporting the samples to a centrallaboratory for analysis. This procedure is time consum-ing, and often leads to inaccurate results due to loss ofsample during transportation.


A monitoring system based on an automatic multipointhas chromatograph has been installed at a landfill, whichis ranked among the top Superfund sites on the NationalPriority list.

This system automatically draws ambient air samplesfrom 16 different sampling points along the perimeter,injects each sample into the gas chromatograph, performsthe analysis, and stores the data on a computer disk. Thefrequency and order in which each site is sampled isoperator controlled.

A specially developed software program enables theoperation of the system, as well as obtaining parametersand retrieval of data from a remote location through theuse of a second computer and a modem.

The description of the operation of the system, its set-up,configuration and performance was discussed.

Alternate sampling strategies for ICP-MS

R. C. Hutton, D. Gregson (VG Elemental Limited, Ion Path,Road Three, Winsford, Cheshire CW7 3BX, UK); W. Vogel,J. D. Steiner, A. Eastgate (ARL, En Vallaire, CH-1024Ecublens, Switzerland)The analytical potentials ofICP-MS have been expandedby the capability of utilizing a variety of sampleintroduction techniques. To date in commercial terms,both laser ablation and electrothermal vaporization areavailable.

There are, however, still many other sampling techniqueswhich can further enhance analysis by ICP-MS. Save forthe use of ultrasonics, the solutions nebulizer has notundergone any significant technical advancement, yetthis area is a key to analytical performance.

A nebulization system which effectively removes 99% ofall solvent and enhances ICP-MS sensitivity by up to 40 xhas been developed. The applications for this device forthe analysis of high purity reagents will be discussed.

Analysis of metal samples can be carried out byLA-ICP-MS. However, there are application areas wherelaser technology may be too sophisticated and expensive.Preliminary results from the coupling of a conductivesolids nebulizer customized for ICP-MS was described.In particular, the performance in a metals process controlenvironment was evaluated.

Automated analysis of industrial waste effluentsusing photo-oxidation with ultraviolet radiation

R. B. Roy, John Swanson and Shirley Arment (ALPKEMCorporation, 14625 S.E. 82nd Drive, Clackamas, OR 97015)Industrial waste effluents are analysed to (i) determinethe compliance of wastewaters, (ii) estimate the toxiceffects ofwaste discharges, and (iii) evaluate the pretreat-ment requirements for reuse of water.

Most frequently, organic carbon, chemical oxygendemand, nitrogen, phosphorous, cyanide and chromiumare determined in a wide variety of industrial wasteeffluents. For the measurement of these parameters,samples are oxidized using either wet chemical oxidationsor ultraviolet-promoted photo-oxidation procedures. Theresulting breakdown products, such CO2 and NH3, aredetermined to establish organic carbon and nitrogencontents, respectively, present in the samples.

The ultraviolet-promoted oxidations are simple andavoid problems which are associated with wet chemicaloxidations and combustion procedures. Photo-oxidationprocedures are also used to clean up colored samples forthe measurement of metal ions.

In this presentation, the application of UV-promotedphoto-oxidation procedures used for the measurement oforganic and inorganic materials present in a wide varietyofwaste effluents were highlighted. In addition, selectionof experimental conditions, interferences encounteredand their elimination were presented.

Automated analysis of reducing sugars in fermen-tation broth

R. B. Roy, Shirley Arment and John Swanson (ALPKEMCorporation, 14625 S.E. 82nd Drive, Clackamas, OR 97015)

Various sugars, molasses and corn syrups are used ascarbon source for the growth ofmicroorganisms in a widevariety of industrial fermentation processes. Measure-ment of reducing sugars ensures the microbial growthand product formation during the operations ofindustrialfermenters.

The fermentation broth consists of insoluble, gelatinousbiomass, the nutrient fluid, and the soluble metabolitesresulting from the fermentation operation. Due to thepresence of polysaccharide materials in biomass, thefermentation broths are, usually, viscous and sticky.Samples are diluted as filtered prior to analysis.

Usually, manual colorimetric, liquid and gas chromato-graphic procedures are used for the determination ofreducing sugars from fermentation broths. For rapid andreliable analysis of reducing sugars, an automatedmethod using an ALPKEM RFA system was developed.Samples are dialysed and the dialysates are reacted withalkaline potassium ferricyanide. The decrease in ab-sorbance, which is proportional to the amount ofreducing sugars, is measured at 420 nm.

The results obtained using the RFA system compare wellwith standard manual methods. The method is sensitiveand can be used to determine reducing sugar content of awide variety of fermentation broths. In addition, theprocedure developed has the potential for on-line moni-toring of reducing sugar contents present in fermentersand/or bioreactors. Thus, ALPKEM RFA system could

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Pittcon Abstracts 1991)

be used as a part ofclosed loop system in which the outputfrom the analyser could be used to automatically controlreducing sugar variations in fermenters. Technical detailsneeded in the transportation of samples to the RFAsystem were also discussed.

Total cyanide analysis by manual standard methodsand automated Kelada method, comparative studyand data evaluation

Nabih P. Kelada (Head of Methodology & Toxic Substances,Metropolitan Water Reclamation District of Greater Chicago);R & D Egan (550 S. Meacham Rd., Schaumburg, IL 60193);and Cecil Lue-Hing (Director of R & D Dept., MetropolitanWater Reclamation Distriuct of Greater Chicago)An automated method for total cyanide has beendeveloped (20 samples/h). In addition to the Bran Lube(Technicon Industrial Systems) AutoAnalyzer IImodules for segmented flow, the system utilized two newautomated units, for ultraviolet (UV) irradiation and forcontinuous thin film distillation. The UV irradiation isperformed in alkaline medium and Pyrex sample coil,thus the strong cyanide complexes (Fe and Co) areeffectively broken down and measured colorimetrically,but not thiocyanate.

The automated Kelada Method is making good progressfor acceptance by the American Society for Testing andMaterials (ASTM). The round robin study for per-formance evaluation has been completed successfully andgave about 5% coefficient of variation, and 90-100%spike recovery for most sample matrixes. The method, asfound by the participants, is applicable to water,wastewater (effluent, raw sewage and sludge) andindustrial discharges. Eventually this method will replacethe present ASTM D-4374 for automated total cyanide.

The present USEPA approved Method 335-2 (same asStandard Method 412-B and ASTM D-2036-A) is timeconsuming ( 11/2 h/sample), has wide variability andfrequently subjected to thiocyanate interference. An indepth study was conducted to compare the manualapproved method with this auomated method. Samplesanalysed were collected from sewage treatment plants(for National Discharge Elimination System, NPDES),and other cases as stated by regulations 40 CFR(aluminum forming, coil coating, electroplating, organicand inorganic chemicals, iron and steel, metal manufac-turing and powders, and petroleum industries). Spikesincluded simple and strong complex cyanides (100-5,000zg/1). Results obtained by both methods show that theyare comparable. However, other than being free fromthiocyanate interference, the automated Kelada Methodconsistently gave far better detection limit (0.5 btg/1),precision, accuracy and spike recovery. Representativedata were presented.

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Water quality control via on-line total organiccarbon determination

Steve H. Vien, Connie M. Courtney, Walt W. Henslee, andJohn M. Leach (Dow Chemical USA, Analytical & EngineeringSciences, Freeport, TX 77541)The analysis of total organic carbon (TOC) is importantto assess the water quality in a water treatment facilityand in chemical processes which do not tolerate highorganic content. In addition, TOC analysis of theincoming stream in a water treatment plant helps pro-tect microorganisms from organic shock. A compositesampling technique followed by laboratory analysis ofthedaily composite sample is commonly used. This methodis generally too slow to respond to plant upsets.

An on-line TOC analyser has been recently evaluated inthe authors’ laboratory and on a process stream. Thisinstrument makes use of the low temperature catalytic airoxidation process to oxidize organics. The instrumentfeatures a unique variable sample volume injection andmulti-ranging system which eliminates the need forsample dilution. Sampling cycles for as short as 3 minutescan be achieved. The principle of operation, analyticalperformance of the instrument, and the results of fieldapplications were presented.

An automatic method to measure agglomerated anddispersed particle size and size distribution

Jason Ruan (Reichhold Chemicals, Inc. P.O. Drawer ’K’, Dover,DE 19903)

Dozens of methods for measuring particle size distribu-tion (PSD) have been developed in the past decades.Among them, microscopic techniques are still the mostreliable and are the industry standard. The drawback ofthese techniques, however, is that they are slow andtedious. Though much progress has been made since theadvent of the image analyser, they have not beensuccessfully applied to resolve agglomerated particles.Even the very sophisticated systems with the de-agglomeration feature can only analyse very narrowdistribution and barely touching particles.

A method has been developed for measuring agglomer-ated, as well as dispersed, PSD from electron micro-graphs. The chord lengths of horizontal lines scannedthrough the micrographs are measured. The chorddistribution is converted to PSD as if all particles weredeagglomerated. A mathematical procedure has beenderived for converting chord distribution, g(1), to PSD,F(x). Non-linear Gaussian regression curve fitting wasalso applied.

The technique has been verified by computer simulationand implemented on a variety of latex samples. They allshow that this technique gives excellent representation ofthe actual particle size distribution. The whole process iscompletely automated and takes less than a minuteinstead of several hours. This method is specially


designed to resolve agglomerated particles, but it is alsoapplicable to micrographs offracture surface for the core-shell structure and/or solid foam analysis.

Automated sample handling and quantitation inlubricant analysis

Jay R. Powell and David A. C. Compton (Bio-Rad, DigilabDivision, 237 Putnam Ave., Cambridge, MA 02139)The analysis of lubrication oils for wear metals by atomicspectroscopy and oil additive depletion, breakdown andcontamination by infrared spectroscopy has been a longestablished technique in this field. The analysis of wearmetals by atomic spectroscopy lends itself to automationeasily because oftwo major factors. First, the quantitativeanalysis is relatively simple, because atomic absor.ption ofa given metal will most often follow a linear Beer’s law fit,or an easily corrected deviation. Second, the relativelyviscous oil can be easily diluted with a solvent such askerosene in order to permit aspiration into the flame orplasma, with the dilution ratio determined by the use ofan internal standard. By contrast, creating an automatedsystem for the analysis of lubricants by infrared spec-troscopy has been much more difficult. Quantitativeanalysis of these fluids is complicated, due to the complexnature of these fluids in terms of both the number ofcomponents and interactions between all the compo-nents. Recent advances in multivariate quantitativetechniques has some promise in overcoming thesedifficulties. In addition, sample handling is complicatedby the fact that no dilution solvent exists that is soluble inthe oil and is infrared inactive. This requires that thesample be transported neat to the sample cell, with a non-interfering solvent used to clean the cell and transportsystem between samples. Here, the design of an auto-mated infrared lubricant analysis system was discussed,dealing with both a comparison of classical quantitativetechniques to multivariate techniques, and how compo-nent architecture can affect sample handling and trans-port in a commercial system.

Designing optimized industrial process analysersfor closed loop control

Hanno Kellner, Gerd Popp and Uwe Grummisch (Bran + LuebbeGmbH, Postfach 1360, Werkstrasse 4, D 2000, Norderstedt,Germany)

Until now the day-to-day application of near infra-redhas been primarily focused on laboratory and ’at-line’analysis. However, the benefits of this technology aremost dramatically realized when the analysis takes placedirectly in the process line.

Process conditions vary from explosion proof environ-ments in the chemical industry to clean-in-place environ-ments in the food and pharmaceutical industries.Therefore, installation of near infra-red analysersrequires optimization of both the analyser design and the

sampling interface. Different approaches will be dis-cussed including filter based systems and fiber opticbased scanning systems.

Full closed loop process control is achievable when thisanalysing approach is combined with precision dosingsystems, weighing electronics and process control units.Real world examples from various types of industry wereincluded in the paper.

On-line multiparameter process analysis utilizingflow injection procedures

Paul Karges and Karl G. Schick (EppendorfNorth America, Inc.,545 Science Drive, Madison, WI 53711)Process analysers must be rugged and dependable.Versatility is usually not as important. Sometimes,however, novel chemistries can be combined with appro-priate hardware to satisfy the requirements for rugged-ness and yet are simple enough so that two parameterscan be measured dependably. Two multi-parameter FlowInjection Analysis (FIA) methods were described, both ofwhich use a single wavelength colorimetric detector and asingle manifold.

The first application determines acidity (up to 25 ppmHC1) and basicity (to 40 ppm KOH) of a complexorganic matrix, 70% of which is toluene. Bromocresolpurple indicator dissolved in 1-butanol is used as thecarrier. A colorimeter operating at 600 nm is used as thedetector. When the carrier is properly adjusted, anincrease in the carrier absorbance is proportional to theconcentration ofpotassium hydroxide while a decrease inabsorbance is proportional to the concentration ofhydrochloric acid.

The second application consists of the measurement ofthe concentration of zinc sulphite (0"1-6%) and sul-phuric acid (2-9%) in a synthetic fibers plant. For thisapplication the normal FIA mixing coil is replaced withan exponential dilution chamber followed by a color-imeter operating at 540 nm. A three-way solenoid valvealternatively switches between the zinc carrier, whichconsists of xylenol orange dissolved in a mixed buffersolution, and the acid carrier, which consists of the samebuffer containing a methyl orange indicator.

An explanation of the exponential dilution chamber,along with a description of how the technique ofelectronic dilution was used to extend the range of thezinc sulphate analysis, was given.

Automated real-time response surface mapping forcontinuous flow systems

Peter D. Wentzell and Nils G. Sundin (Trace Analysis ResearchCentre, Department ofChemistry, Dalhousie University, Halifax,Nova Scotia, Canada B3H 4J3)The development of continuous flow methods of analysisoften requires the optimization ofnumerous experimentalparameters. Because of the complex interactions among

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these variables, empirical optimization strategies, such asthe simplex method, are usually preferred when theprimary objective is to obtain the optimal operatingconditions. If the objective is to obtain a better under-standing of variable interactions, however, systematicresponse surface mapping (i.e. response vs. experimentalvariables) with an appropriate experimental design ismore useful. One way to perform both of these tasksefficiently and reliably is through the use of a computer-controlled continuous flow apparatus. In this talk, theimplementation of a highly automated continuous flowsystem constructed in our laboratory was discussed.

One of the drawbacks to existing response surfacemethods is that they are normally carried out off-line, i.e.after all experiments are complete and the apparatus hasbeen shut down. While this permits fairly comprehensivedata analysis, it eliminates any kind of immediateexperimental feedback. The authors have developedsoftware which allows three-dimensional response sur-face maps to be viewed while the experiments are inprogress. This provides some distinct advantages, par-ticularly for investigating noisy, suspicious, or unusualregions of the surface. Also, since the time lag betweenexperiments is small, conditions are more reproducible.The details of this approach were illustrated through itsapplication to a hydride generation/atomic absorptionsystem for the determination of arsenic.

Response surface display methods employ several strat-egies, all of which possess certain advantages whenapplied to experimental systems. The most basic methodis the generation of ’stick plots’ in which the data aredisplayed as vertical lines in a 2-dimensional projection ofa 3-dimensional space. This has the advantage ofproviding a true representation of the measurements, butgives a poor perspective on the overall shape of thesurface and is not as visually pleasing as the morecommon ’wire frame’ representations. The generation ofwire frame surfaces or topographical maps requires thatthe data be modelled however, and this always runs therisk of imposing artificial structure on the data.Polynomial modeling and triangulation with simple orcomplex interpolation are the most common approachescurrently used. Because the ideal rnodeling methoddepends on the nature of the chernical data set, theautomated system developed in our lab makes a variety oftechniques available. This permits more thorough exam-ination ofvariable interactions while the experiment is inprogress. Methods for improving the efficiency of themapping procedure through alternatives in experimentaldesign have also been considered.

On-line process analyser for chemically boundnitrogen and sulfur compounds

James S. Wreyford (Antek Instruments, Inc., 300 BammelWestfield Road, Houston, TX 77090)Bench top analyses of nitrogen compounds by pyro-chemiluminescent nitrogen specific detector and sulfurcompounds by pyrofluorescent sulfur system have been

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successfully utilized in various academic and industriallaboratories for several years. The need for on-linenitrogen and/or sulfur analyses in the industrial food andchemical processing plants and refineries prompteddevelopment of an on-line process system using con-tinuous flow and/or discreet sampling techniques.

The analytical techniques, sensitivity, as well as linearityand repeatability of response were discussed for water,liquid hydrocarbons, and gas applications.

A new method for chromium determination inchrome-phosphate treatment on aluminum surface

Richard F. Puchyr and Ravi Raja (American National CanCompany, 433 N. Northwest Highway, Barrington, IL 60010)The passivation of the surface ofaluminum coils used forproduction of food cans is crucial for good adhesionbetween the aluminum and the organic coating applied tothe metal surface. A chrome-phosphate chemical treat-ment is applied to aluminum coils for this purpose.Chromiun content seems to be the most important factorthat determines the adhesion.

There are methods using X-ray fluorescence spec-troscopy to determine the amount of treatment onaluminum coils, but all require known aluminum platestandards. There has not been an established method todetermine the amount of chromium in the treatment onan aluminum surface. Since different aluminum suppliersuse different formulations, the same weight of treatmentfrom two suppliers may not have the same chromiumcontent. Therefore, it is important that there is a methodto determine the chromium content itselfwhen no knownplate standards are available. Once the chromiumcontent is known the chemical treatment levels canreadily be determined by any supplier.

The authors have developed a method for this purpose.This method uses a combination of atomic absorptionand direct reading emission spectroscopic techniques.The method consists of removing the treatment usinghydrochloric acid and determining the chromium contentin the acid solution by an atomic absorption procedure. Asmall amount of chromium in the aluminum that isusually removed with the chromium treatment con-tributes to the chromium content determined by AA. Acorrection for this is made by determining the alloychemistry of the coil by a Direct Reader emissionspectrometer and compensating for the chromium con-tribution from the alloy that dissolved into the acidsolution.

As an offshoot of this method, the authors have alsoderived a fast indirect method for determining the relativetreatment levels on the aluminum coil by using a DirectReader emission spectrometer, using known standards.

Pittcon Abstracts 1991)

The automation ofan atomic absorption spectometerfor on-stream analysis of total iron in zinc sulphatesolutions

Michael Knowles, Fred Delles (Varian Optical SectroscopyInstruments, 201 Hansen Court, Suite 108, Wood Dale, IL60191); D. L. Hoobin (Vrian Pty. Ltd., 11-13 Palmer Court,Mount Waverley, Victoria3071, Australia); B. R. Champion andM.J. Howell (Pasminco Metals-EZ, GPO Box 377D, Hobart,Tasmania 7001, Australia)

This paper described the design of an automated on-stream analysis system for the determination of total ironin zinc sulphate solutions. The Pasminco Metals-EZNeutral Leaching Plant removes iron from zinc plantelectrolyte by leaching impure zinc oxide with acidicspent electrolyte. An iron dosing solution is supplied tothe plant to maintain the Fe(III) concentration at thedesired level.

A fully automated system was described which isprogrammed to periodically sample plant solution andprepare the sample for analysis by an autotitrator forFe(II) and an atomic absorption spectrometer (AAS) fortotal iron. The Fe(III) level is calculated as the differenceand is used to control the flow ofiron dosing solution. TheAAS has provision for user written software for instru-ment control via a GP10 communications utility, whichhandles up to 12 digital outputs and 14 digital inputs, 2RS232C ports and an HP-GPIB port. An Opto 22 solidstate Input/Output (I/O) interface was assembled toactivate the flame and the stream selector system duringeach analysis.

Other I/Os synchronize and advise analyser status to theplant-wide Taylor MOD 300 Distributed Control System(DCS). Customized software had been prepared for theAAS system to control the analysis and to allow theprogramming of additional VDU displays and compu-tations and for the computed results to be sent to theMOD 300 DCS via an RS232C data link.

Aspects of the system design and implementation werediscussed, including the software design approach, thedetails of the analysis and aspects of interfacing andsafety.

Intelligent automated laboratory systems

H. M. Kingston, F. ’A. Settle,* M. A. Pleva,** P.J. Walter;G. W. Krarner and L. B. Jassie (Consortium on AutomatedAnalytical Laboratory Systems (CAALS), National Institute ofStandards and Technology, Center for Analytical Chemistry,Inorganic Analytical Research Division, Gaithersburg, MD20899; * Department of Chemistry, Virginia Military Institute,Lexington, VA 24450; ** Department of Chemistry, Washingtonand Lee University, Lexington, VA 24450)Industrial and government operations both dependheavily upon the analytical laboratory for chemicalmeasurements. These measurements provide criticalfeedback in research, acceptance testing, environmental

quality, and quality assurance. The field of chemicalanalysis has become instrument based and is now capableof being integrated into an autoInated laboratoryenvironment. Integrating instrumentation into analyticalsystems that automate complete analyses is difficult dueto incompatibilities in hardware, software, and sampletransport. Several key issues have been identified that willhave a positive effect on the development ofmore efficientinstrumentation in the automated laboratory. Theseissues include instrument modularity, intelligence, com-munication, and integration and must be addressed toprovide the highest level of sophistication for thelaboratory.

The National Institute of Standards and Technology(NIST) has ,joined with US industry to form theConsortium on Automated Analytical LaboratorySystems (CAALS). The Consortium seeks to acceleratethe development of automated analysis methods andsystems, to improve efficiency and data quality, and topromote transferability of analytical methods.

The automated systems developed will integrate chemi-cal analysis expertise (intelligence), provide recom-Inended methods for utilizing modular analytical instru-mentation, and incorporate quality assurance proceduresinto the automated methods.

The first component of the system, an automatedmicrowave decomposition station, has been developed. Itcan be controlled by a prototype expert system that isbeing developed to assist the analyst in establishingprocedures for nicrowave dissolution. The entire systemwill consist of three modula designed components. Thesecomponents represent fundamental steps in inorganicanalysis, specifically analysis release, separation anddetection. The specific modules that will be combined toperform these functions are microwave decomposition,chelation chromatography, and ICP-OES and/or MS.The system was discussed emphasizing intelligentcontrol.

Intelligent, automated laboratory systems

Frank A. Settle,,Jr (Department of Chemistry, Virginia MilitaryInstitute, Lexington, VA 24450)

Although many laboratories have dmnonstrated that theautomation of one or two steps of an analytical methodcan improve both the quantity and quality of results, fewmethods have been totally automated. Critical problemareas in implementing automated methods are methoddevelopment and method validation. The resourcesrequired for automation are often lacking in laboratorieswhere automation is needed most. Once an automatedmethod has been validated it can be transferred electron-ically among laboratories with identical automationcomponents.

An intelligent laboratory system to expedite the design,optimization, validation and transfer of automatedanalytical methods was described. This system

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integrates existing software for experimental design,statistical analysis, expert system development andlaboratory automation with the components required forsample preparation and analyte measurement. Althoughmost ofthe components are commercially available, it hasbeen necessary to develop programs to facilitate com-munication among components.

The hardware and software components should becompatible and interchangeable to facilitate efficientconfiguration, optimization and transfer of automatedmethods. The preliminary results from colorimetricdeterminations oforthophosphates in water samples werepresented.

This work was funded in part by NSF Grant #CHE-.8805930, Zymark Corporation and a grant from the VMIFoundation.

Flow injection analysis of glutamate with a gluta-mate oxidase reactor and acridinium ester chemi-luminescence detection

Maureen Stuever Kaltenbach and Mark A. Arnol

Documents

Vol. Pittcon Abstracts (1991)Different forms of metals and metalloids have varying degrees oftoxicity in biological systems. Becauseofthis, therehasbeenanincreasein the researchfocusedonthe