Manual vs. Automated Methanol Extractions

Jeramiah BradleyApplication ChemistTeledyne Tekmar at Mason, OH

Table of Content

• Background Teledyne Tekmar • Brief Overview on Purge and

Trap

• Atomx XYZ and key features• Methanol Extractions

• Manual• Automated• Tips for methods and

conditions

Purge and Trap Overview

A measured amount of a sample is placed in a sealed vessel.

The sample is purged with an inert gas causing the VOCs to be swept out of the

sample and retained on an analytical trap.

The trap is heated and the VOCs are swept onto the GC by back flushing the trap with

an inert gas.

Atomx XYZTeledyne Tekmar Atomx XYZ is a Purge and Trap Concentrator/Multimatrix Autosampler.

• Capable of running water, soils, and methanol extractions.

• 84 position 40mL VOA vial capacity w/ optional chiller tray

• Methanol rinse and/or patented dual-stage water heater

• Automated Methanol Extraction

• Mass Flow Controller (MFC)

• Moisture Control System

Vial Handling

Needle 3 stage concentric needle.

ElevatorVial heater temperature range of 35°C to 80°C

Trap cooling system

Optional chiller tray

Sample Gas Handling

Uses Helium, or Nitrogen as inert carrier gas.

Entire heated pathway settable to 250 C

Trap door interlock switch turns off trap heating power if door is open to prevent accidental injury.

Heated 6 port valve. Controllable temperatures from of 35-250 C

Moisture Control System (MCS) reduces water vapor transferred to the GC by 50%

Mass flow Controller enables automated leak checking. Capable of flow rates between 5 to 500 mL/min.

Liquid Handling

25 mL syringe that allows for sample volumes in 1 mL increment. 1/16” OD PEEK tubing for liquid transfer.

Dilution capabilities of up to 1:100

3 standards dosing valves for internal standards, surrogates, and matrix spikes can vary volumes in 1, 2, 5, 10, and 20 uL aliquots with no waste.

Multiport valve for sample, methanol, water, and drain controls.

Sample Pathway

• Standard # 9 U-shaped analytical trap for superior chromatography

• PEEK• Inertium,• Silcosteel• PTFE• Flow diagram

Atomx XYZ

Compared to its previous predecessors it has• 22 % faster trap cool down.• 52 % less plumbing connections in the

manifold.• 50% less water vapor transfer to GC.

More details can be found at https://store.teledyneacs.com/account/login

https://store.teledyneacs.com/account/login

Methanol Extraction

A sample preparation technique for GC and GC/MS:

• A solid sample with a VOC concentration of greater than 200 ug/kg is sampled in the field.

• The sample is placed in a vial• Methanol is added to the vial and then sealed.• Mixing or agitation is applied to the vial to aid in the VOC

extraction from soil to methanol.

• Depending on the concentration, an aliquot of the methanolic solution is added to DI water and analyzed under normal Purge and Trap parameter.

Atomx XYZ EPA method 5035 Capabilities

• Direct purge in a 40 mL vial

Low level-soil mode

• Uses a programmable automatic dilutions of methanol extract by pulling 50 µL, or 100 µL aliquots for 5 mL sample volumes.

High Level soil-Methanol extraction mode

Parameters of Water mode vs Methanol ExtractionParameters highlighted in yellow were not used.

Parameters of GC/MS

Manual MethodUtilizes the water mode method of the Atomx XYZ with manual dilutions

• 40 ml vials—add 5 g or 7 g of sample sand, or soil• Add 5 uL surrogate standard.

• Add 10 mL methanol to 5 g samples, add 7 mL methanol of 7 g sample• Sonicate vials for 20 minutes

• Using a 50 mL volumetric flask fill almost to volume with DI water, add 2 mL of samples, fill the volumetric to volume with DI water. Invert 3 times and fill 40 mL vials to volume leaving no air bubbles.

• Make a 40 mL vial for each sample.• Place on autosampler for water method mode analysis.

Automated MethodUtilizes Methanol Extraction mode

• Add stir bar to a 40 mL vial containing the 5 g, or 7 g of soil.• Place on autosampler for methanol extraction analysis.

Basics

• Conversions to remember:• 1 ppm = 1000 ug/kg = 1 mg/kg = 1 ng/ul• 1 ug/kg = 1 ug/L = 1 ppb = 1 ng/g• 1 ul = 50 ng• 5000 ng/g

• Equations to remember:C₁V₁=C₂V₂RRF=𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 ×𝐼𝐼𝐼𝐼(𝐶𝐶𝐶𝐶𝐴𝐴𝐶𝐶𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐶𝐶𝐶𝐶𝐴𝐴)

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐶𝐶𝐶𝐶𝐴𝐴𝐶𝐶𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐶𝐶𝐶𝐶𝐴𝐴 ×𝐼𝐼𝐼𝐼(𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴)

Similarities• Dilutions (sample volume)• Extractions• Internal standard of 5 ul• Purged in sparger.

Key differences

•Effort•Internal standard vial 3

Results for check Standards

* indicate units in ppm. (n=10, 100 ppb)

Tips for method and conditions

• Wetting the sand, or soil with water-miscible organic solvent.• Polar compounds on matrix

• Methanol is hydroscopic so be sure to cover.• Heating sparge vessel.

Thank You for Attending this Webinar!

• Feel free to list any future topics for webinars that you would like to see below.

• If you have any question feel free to email me at the address below and respond within 24 hours.

• Email: Jeramiah.Bradley@Teledyne.com• Be safe!

Slide Number 1Table of ContentPurge and Trap OverviewAtomx XYZVial Handling Sample Gas HandlingLiquid HandlingSample PathwayAtomx XYZMethanol ExtractionAtomx XYZ EPA method 5035 Capabilities Parameters of Water mode vs Methanol Extraction� Parameters of GC/MSManual Method�Utilizes the water mode method of the Atomx XYZ with manual dilutions Automated Method�Utilizes Methanol Extraction modeBasicsSimilaritiesKey differencesResults for check StandardsTips for method and conditionsThank You for Attending this Webinar!