Upload
phungtu
View
232
Download
0
Embed Size (px)
Citation preview
The potential of paper-based microfluidicdevices and passive samplers in chemicaldevices and passive samplers in chemical
oceanographic monitoring
Spas D Kolev
School of Chemistry, Center for Aquatic Pollution Identification and Management (CAPIM)
Th U i it f M lbThe University of Melbourne, Victoria 3010, Australia
Passive samplers
Deployed over extended periods of time (e.g. days, weeks) to provide
time-weighted average concentrations of the target chemical species
Low cost (no moving parts or power source) Low cost (no moving parts or power source)
Provide preconcentartion of the target chemical species
Allow the determination of labile species which are potentially
bioavailable
Small and mechanically strong (e.g. deployable in difficult to access or
‘hostile’ environments)
No special training is required for their handling
Passive samplers applied to marine systems
Polar Organic Chemical Integrative Samplers (POCISs)
Chemcatcher3M EmporeTM
disksdisks
Applications: Pharmaceuticals, pesticides (LOD – 0.01 – 1.5 M/L)Alkylphenols PAHs
Applications: Hg(II) (LOD – 1.7 ng/L)Organotin (LOD – 3 ng/L)P ti id
Alkylphenols, PAHs
S Seethapathy, T Gorecki, X Li, J. Chromatogr. A 1184 (2008) 234.
Pesticides
Passive samplers
Diffusion Gradient in Membrane Stripsus o G ad eThin-film (DGT) sampler Applications:
DDT, PCB (polyethylene)Pesticides (ethylene – vinyl acetate)Dioxines, furans, PCB (polyoxomethylene)
Binding layerDiffusive gel layerFilter membrane
Dioxines, furans, PCB (polyoxomethylene)
Outer sleeve
Base
Semi-Permeable Membrane Devices (SPMDs)
Applications: phosphate
Applications: Al(III)
Ferrihydrite
Applications: phosphate
Porous membrane
Ferrihydrite
Polymer Inclusion Membranes (PIMs)Composition: Base polymer (e.g. PVC, cellulose triacetate)
Extractant/Carrier (e.g. Aliquat 336, di(2-ethylhexyl)phosphoric acid (D2EHPA))
Plasticizer/modifier (e.g. 2-nitrophenyl octyl ether, dioctylphtalate, n-decanol)
Physical characteristics Homogeneouso oge eous Transparent Flexible and mechanically strong
Advantages: Longer lifetime than supported liquid membranes due to the reduced loss of the membrane liquid phase.
LD Nghiem, P Mornane, ID Potter, JM Perera, RW Cattrall, SD Kolev, J. Membr. Sci., 281 (2006) 7.M O’Rourke, RW Cattrall, SD Kolev, I.D.Potter, Solvent Extr.Res.Development, Japan 16 (2009) 1.MIGS Almeida, RW Cattrall, SD Kolev, J. Membr. Sci. 415-416 (2012) 9.
Preparation of the Zinc(II)-selective PIM
PIM composition:
PVC D2EHPA +PVC
glass ring
in THFD2EHPA (di-2-ethylhexyl phosphoric acid)
flat glass plate
OPO OO g p
SD Koleva, Y Baba, RW Cattrall, T Tasaki, N Pereira, JM Perera, GW Stevens, Talanta 78 (2009) 795.LL Zhang, RW Cattrall, SD Kolev, Talanta 84 (2011) 1278.LL Zhang, RW Cattrall, SD Kolev, Talanta 97(2012) 382.
PIM-based Zinc(II) passive sampler
Source phase: Zn(II)s + 3/2(HR)2 m ZnR2.HR m + 2H+s
Receiving phase: ZnR2.HR m + 2H+r Zn(II)r + 3/2(HR)2 m
S b i t f t i i d b hSubscripts s, r, m refer to source, receiving and membrane phases.
Paper-based microfluidic devices
Main characteristics
Liquids are transported by capillary force along hydrophilic (penetration) channels.
Optical detection is based on visual assessment of the colourintensity (colour charts) or colour intensity measurements.
Main advantages
Low cost
Portable
Disposable
Flexible in terms of design and the analytical reaction usedg y
Easy to use
Determination of orthophosphate
H2SO4Ammonium molybdateP t i ti t t tAscorbic acid Potassium antimony tartrate
Sample (10 L)
BM Jayawardane, ID McKelvie, SD.Kolev, Talanta 100 (2012) 454.
Optimization and calibration of the CardParameter Range studied Optimal value
Sulphuric acid concentration [M] 5.0 – 8.0 6.6
Volume of the molybdate/antimony (Mo/Sb) reagent [L] 0.25 - 1.5 0.5
Volume of the ascorbic acid reagent (75 mM) [L] 0.5 – 2.5 1.5
Molybdate concentration in the Mo/Sb reagent[mM] 42 - 210 126
Antimony(III) concentration in the Mo/Sb reagent[mM] 6 - 42 6
Reaction time [min] 5 - 90 10
Analytical figures of merit
Linear concentration range 2 (mg L-1 P) 0.2 – 10
Detection limit (mg L-1) 0.05
RSD (%) at 5 mg L-1 P 1.6RSD (%) at 5 mg L P 1.6
Stability ambient temperaturefreezer
15 days122 days
BM Jayawardane, ID McKelvie, SD.Kolev, Talanta 100 (2012) 454.
Interference studies
P standard Added Si P found
Si interference
[mg L-1 P] [mg L-1 Si] [mg L-1 P]1.0 0 0.98 (0.08)
1.0 1.0 0.98 (0.09)1.0 1.0 0.98 (0.09)
1.0 2.0 0.98 (0.08)
1.0 5.0 0.99 (0.06)
1.0 10.0 0.98 (0.06)
BM Jayawardane, ID McKelvie, SD.Kolev, Talanta 100 (2012) 454.
Analysis of SRM and Natural SamplesAnalysis of SRM and Natural Samples
Determination of Cu(II)
Parameter Optimal valuePVC (%) 49.5
D2EHPA (%) 40.0
DOP (%) 10.0
1-(2’-pyridylazo)-2-naphthol (PAN) (%) 0.5
Hydrophilic zone pH 2 0Hydrophilic zone pH 2.0
Sample volume (µL) 20
Colour development time (min) 15
Sample pH 2 - 7
BM Jayawardane, L dlC Coo, RW.Cattrall, SD.Kolev, Anal. Chim. Acta (submitted).
Calibration of the Card
Linear concentration ranges (mg L-1 Cu) 0.1 – 1.0 / 1.0 – 301
Analytical figures of merit
Detection limit (mg L-1) 0.06
Stability (ambient temperature) > 5 months
Natural samples
No interference up to 30 mg L-1 (1 mg L-1 Cu) of: Fe(III), Al(III), Zn(II), Cd(II),Pb(II), Ca(II) , Mg(II)
Sample Origin AAS
[mg L-1 Cu]
Card
[mg L-1 Cu]( ) ( )
p
Hot water 1 0.70 (0.01) 0.72 (0.01)
Hot water 2 0.24 (0.01) 0.21 (0.02)
Hot water 3 0 26 (0 01) 0 24 (0 02)Hot water 3 0.26 (0.01) 0.24 (0.02)
Hot water 4 1.32 (0.20) 1.11 (0.03)
Mine tailings water 1 7.80 (0.20) 7.56 (0.21)
Mine tailings water 2 7.70 (0.20) 7.55 (0.18)
BM Jayawardane, L dlC Coo, RW.Cattrall, SD.Kolev, Anal. Chim. Acta (submitted).
ConclusionsConclusions
Passive samplers provide valuable information on the time-ass e sa p e s p o de a uab e o at o o t e t eweighted average concentrations of chemical species of interest.
Polymer inclusion membrane (PIM) offer high selectivity, flexibility and sensitivity in passive sampling.
The proposed Cards provide a low-cost, fast and simple platform for the quantitative analysis of aqueous samples forplatform for the quantitative analysis of aqueous samples for nutrients and heavy metals.
The Card approach offers a number of advantages (minimal The Card approach offers a number of advantages (minimal sample and reagent manipulation and consumption, straightforward quantification).
Both techniques could provide valuable analytical information in oceanographic studies at low cost.
AcknowledgmentsAcknowledgments
Professor Robert Cattrall (The University of Melbourne)Principle Research Fellow Ian McKelvie (The University of Melbourne)Professor Wei Shen (Monash University)Associate Professor Lilibeth Coo (University of the Philippines)
l id ( h i i f lb )Dr Ines Almeida (The University of Melbourne)Dr Vincent Pettigrove (Melbourne Water Corporation)Mr. Rhys Coleman (The University of Melbourne)
Mrs. Manori Jayawardane (The University of Melbourne)Ms. Lujia Zhang (The University of Melbourne)Mr Cleopas Chan (The University of Melbourne)Mr. Cleopas Chan (The University of Melbourne)
Australian Research Council (DP1094179 LP110200595)Australian Research Council (DP1094179, LP110200595)Victoria's Science Agenda Investment FundMelbourne Water CorporationMelbourne Water Corporation