Air Monitoring

  • A Complete Solution for Soil Gas Analysis
  • Table 1: Precision, linearity, and reporting limits generated by this study.
  • Table 2: Precision of the automated internal standard (n = 15).

A Complete Solution for Soil Gas Analysis

Jul 11 2018 Read 652 Times

Introduction

The sampling and analysis of soil gas using automated thermal desorption (ATD) coupled with gas chromatography/mass spectrometry (GC/MS) poses several unique challenges when compared to indoor or ambient air monitoring. PerkinElmer®, Inc. have designed and patented a new sorbent tube that successfully accommodates the challenges of soil gas sampling and analysis using EPA Method TO-17, while out performing regulatory criteria for detection limits, accuracy and analyte range.

Key Objectives

  • Extend the analyte range
  • Ensure the most volatile compounds are retained during sampling
  • Recovery of all semi-volatiles
  • Enable “quick clean up” of the tubes
  • Enhance water management
  • Increase sampling volumes to improve upon regulatory limits, if needed

The Study

After samples were collected in the sorbent tubes, the tubes are loaded onto the automated thermal desorption (ATD) autosampler. A leak check is then performed on both the sample tube and the concentrator trap to ensure sample integrity. The concentrator trap employs a Peltier cooler instead of liquid cryogen to achieve the trap’s lower temperature. The low dead volume trap contains hydrophobic sorbents; therefore, the analytes are focused on the trap in such a way that breakthrough of this suite of analytes does not occur.

After the contents of the tube are desorbed onto the concentrator trap, the trap is heated rapidly, and the compounds from the trap are introduced into the GC analytical column in a narrow band.

For highly concentrated samples, two splitters may be employed: an inlet split between the sample tube and the concentrator trap, and an outlet split between the concentrator trap and the analytical column, enabling split ratios of several orders of magnitude. A surrogate can be automatically spiked onto all tubes prior to sampling incorporating additional validation of samples.

Experiment

The instruments used in this study were the PerkinElmer TurboMatrix™ Thermal Desorber 650 (ATD), Clarus® 680 Gas Chromatograph (GC) and the Clarus SQ 8 Mass Spectrometer (MS).

A high temperature volatile column was used, enabling extension of the hydrocarbon range past naphthalene while still focusing the most volatile compounds. 86 target compounds and diesel were investigated.

The standards were diluted with purge and trap grade methanol to attain the required concentration for the following experiments: Breakthrough, Recovery, Water Management, Precision, Dynamic Range, and Detection Limits.

Results

As demonstrated in Table 1*, the data collected shows that precision, linearity and reporting limits are all excellent for all classes of compounds and out performs all regulatory requirements and easily meets Method TO-17 performance criteria. The reporting limits are calculated using a 1 litre sample volume. The dynamic range achieved was four orders of magnitude across the target component list. The results from an automated internal standard precision study are presented in Table 2*. (Please see images*)

For further information please click here.

Read comments0

Do you like or dislike what you have read? Why not post a comment to tell others / the manufacturer and our Editor what you think. To leave comments please complete the form below. Providing the content is approved, your comment will be on screen in less than 24 hours. Leaving comments on product information and articles can assist with future editorial and article content. Post questions, thoughts or simply whether you like the content.


Digital Edition

International Environmental Technology October 2018

October 2018

In This Edition Gas Detection - Flammable Gas Dectection In Coal Mines - Protective concepts in combustible gas and vapor detection - The only line of gas sensing elements with SIL2 capabil...

View all digital editions

Events

NSC Conress & Expo

Oct 20 2018 Houston, USA

WETEX 2018

Oct 23 2018 Dubai, UAE

Pol Eco System

Oct 23 2018 Poznan, Poland

WASMA

Oct 23 2018 Moscow, Russia

View all events