Comparing EPA method 8260 C & D

Jeramiah BradleyApplication ChemistTeledyne Tekmar at Mason, OH

Table of Contents

• Background Teledyne Tekmar

• Brief Overview of Purge and Trap

• Changes made from EPA method 8260 C to D

• Challenges and Observations

• Tips• Results of each method using

prep method 5030 and 5035

Purge and Trap Overview

A 40 mL VOA vial is collected headspace-free and capped.

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

the GC carrier 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

Atomx XYZ EPA method 5030 Capabilities

• Automatically withdraws up to 25 mL of aqueous sample volume into sparger.

Aqueous Samples

Atomx XYZ EPA method 5035 Capabilities

• Direct purge in a 40 mL vial

Low level-soil mode

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

High Level soil-Methanol extraction mode

Water MethodUtilizes the water mode of the AtomxXYZ

Soil Method

• Clean water blanks being drawn from reservoir are not the same as vial blanks.

EPA Method 8260 D

• Method used to determine volatile organic compounds in a variety of solid waste and water matrices.

• Changes: Terminology of area or height changed to response. Mass to m/z.• Tune updated from once every 12 hrs to once prior to ICAL.

• BFB tuned: 96 m/z relative abundance expanded from 5 to 15 % when using H2

Similarities Between C & D

No Changes

• ICAL Verification (SCV)• Continuing Calibration

Verification (ICV/CCV)• Laboratory Control Sample (LCS)• Duplicates and Matrix Spikes• Surrogates• Qualitative Analyte Identification

Quality Control

Changes made from C to D QUALITY Control

Instrument performance check

Initial Calibration (ICAL)

Blanks

Internal Standards

Annual Verification of LLOQ

Differences

Prior to ICAL; no longer every 12 hrs. Modeled after 524.3 tune criteria.

Updated and reorganized.

Must run after ICAL and prior to sample. Method blanks must be less than 1

2LLOQ , or 1

10of sample concentration.

IS area ICV/CCV will be compared to midpoint of ICAL.

Performed annually and after significant changes are made.

QC requirements

Hydrogen GCMS behavior

• Lower viscosity promoting faster and sharper peaks.• Can alter injection, column phase and detector operation.

• Injector reactive surfaces• Routine maintenance

• Column Chromatography • Flow rate impact on peak shape. Use narrower bore column to reduce pressure and prevent

ionization. (0.18 mm ID or smaller)

• Detector• Hydrogen can become ionized and interfere other analyte mass spectra. Can reduce response of

target compounds by 2-5x when compared to helium

• Reactivity can promote background in detector.

Challenges and observations

When using hydrogen as a carrier gas for your GC/MS:

• Lower end sensitivity issues may be further complicated by hydrogen carrier gas causing difficulties up to 5ppb.

• Larger RF at lower curve.• Bias calculated range for lower curve when using linear regression.• Higher RSD the lower you go for the curve.• Gas compounds; retention shift and splits of coeluting compounds,.• Dehydrogenation due to hydrogen carrier gas.• Elevated base line when using hydrogen gas compared to Helium.• Sensitivity reduction comparison to Helium.

Quick Look: He and H2

Tips for method and conditions

• Safety first! Check for leaks as the gas is more prone to leaks.• Configure GC for hydrogen to ensure proper flow.• Slower flow rates and lower split ratios to reduce protonation and increase

sensitivity.• Clean source to reduce baseline.• Liners may need to be changed more frequently.

Typical trends

Halogens Ketones Gases

Aldehydes Ethers (Oxygenates) Acetates

List of known trouble compounds based off Section 1.3

• May experience trouble with recovery when using sample prep methods 5030 or 5035.

GC/MS Parameters

Parameters of Water mode vs Soil modeParameters highlighted in yellow were not used.

BFB: Passing 8260D Criteria

(carrier hydrogen)

Results of target compounds*denotes linear regression ** denotes quadratic regression

GC/MS Parameters

8260 Total Ion chromatogram: Hydrogen Carrier gas vs Helium

VMS – 20m x 0.18 x 1.0µm

Helium

Hydrogen

Methylene Chloride Acetone

Methylene Chloride

Acetone

1,1-Dichloroethane

DiisopropylEther

DiisopropylEther 1,1-Dichloroethane

Chloroethane

Chloroethane

8260 Total Ion chromatogram: Hydrogen Carrier gas vs Helium

VMS – 20m x 0.18 x 1.0µm

Hydrogen

Helium

Pentafluorobenzene

1,2-DichloroethaneBenzene

Methacrylonitrile

Benzene

1,2-Dichloroethane

Pentafluorobenzene

Methacrylonitrile

Tetrachloroethylene

Tetrachloroethylene

Trans-1,3-Dichloropropene

Trans-1,3-Dichloropropene

8260 Total Ion chromatogram: Hydrogen vs Helium Carrier

• Some coelution, but similar retention times, responses, and peak shapes.

Hydrogen

Helium

p-Isopropyltoluene 1,3-Dichlorobenzene

p-Isopropyltoluene 1,3-Dichlorobenzene

8260 D TIC of Water vs Soil Mode

Soil

Water

Thank You for Attending this Webinar!

References1. U.S. EPA. 2018. "Method 8260D (SW-846): Volatile Organic Compounds

by Gas Chromatography/Mass Spectrometry (GC/MS)," Revision 4. Washington, DC.

2. U.S. EPA. 2006. “Validated Test Method 8260C: Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS)," Revision 3. Washington, DC.

• Any questions?• Feel free to list any future topics for webinars that you would like to see

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