1,4-Dioxane Determination by GC Purge and Trap

Abstract

1,4-dioxane is a volatile organic compound found at residual levels as an impurity in many cosmetics, personal care products, household cleaners and is commonly used as a cleansing agent during the manufacturing of pharmaceuticals.  It is also employed as a stabilizer for chlorinated solvents, so it is commonly found at industrial sites contaminated with these solvents.  Furthermore, when 1,4-Dioxane is released into the environment, there is a potential for it to migrate into the groundwater.  The Environmental Protection Agency (EPA) has classified 1,4-dioxane as a likely carcinogen and thus it is essential to be able to detect 1,4-dioxane at low concentration levels. 1,4-dioxane has been identified as a potential carcinogen to humans according to the International Agency for Research on Cancer (IARC) as well as the Department of Health and Human Services National Toxicology Program (NTP)
 

Introduction

1,4-Dioxane is completely miscible in water and does not readily biodegrade in the environment.  Due to its miscibility in water, 1,4-dioxane has very poor purge efficiency during purge and trap testing and as a consequence, higher detection limits. As a result many many Environmental labs face challenges.  There are many discussions and peer to peer exchanges including several on Chromatography Forum.

In order to better detect 1,4-Dioxane, many laboratories use a heated purge cycle and/or purge larger volumes of samples.  Furthermore, laboratories employ the Selective Ion Monitoring (SIM) mode of the Mass Spectrometer (MS) for better detection.
 

During purge and trap testing problems with some instruments can exist with 1,4-dioxane due to the fact that it tends to remain in the sparge vessel even after rinsing which can lead to carryover.  Thus, many labs run 1,4-dioxane water samples in soil mode in order to avoid this problem.  The EST Analytical Centurion WS autosampler has a patented water transfer mode that automates the water sample transfer to a separate vial for sample purging in the soil station while complying with USEPA Method 5030 requirements of keeping the sample vial closed before sample purging.  This application will examine 1,4-dioxane sampling and analysis using purge and trap concentration of water samples using the EST Analytical Evolution concentrator and the soil mode of the Centurion WS autosampler.

1,4-Dioxane