![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
R9 Laboratory SOP 307
Analysis of 1,4-Dioxane by Heated Purge & Trap GC/MS
Summary
This procedure is for the determination of 1,4-dioxane in aqueous samples. The quantitation limit of the method is 5 μg/L. The applicability of this procedure is specific to project data quality objectives and must be assessed on a case by case basis.
This Standard Operating Procedure (SOP) describes the procedures used for the analysis of 1,4- dioxane in the Region 9 Laboratory. 1,4-Dioxane is purged from 25-mL water samples in a heated fritted sparge cell.
An inert gas (helium) is bubbled through the sample in the heated sparge cell, which purges the target compound from the sample onto a trap containing an adsorbent material, which retains the analyte at ambient temperature. After the purging of the sample is completed, the adsorbent trap is heated and back flushed with helium to desorb the analyte onto a capillary column. The capillary column separates the analyte from potential interferences, and the effluent is swept into the mass spectrometer (MS) detector. The MS operates in the selective ion monitoring (SIM) mode, detecting specific ions.
The samples are spiked with an internal standard (IS). The target volatile organic compound is identified in the sample by analyzing standards under the exact same conditions employed for samples, and comparing the resulting mass spectra and GC retention times. A response factor is established for the target compound during the initial and continuing calibrations by comparing the MS response of the primary ion produced by the target compound to the MS response for the primary ion produced by the associated internal standard. The target compound is quantitated by comparing the responses of the target compound to the internal standard in the sample, using the response factor from the most recent continuing calibration.