Low Level Analysis of 1,4-Dioxane by EPA Method 8270C SIM with Large Volume Injection
1,4-Dioxane has been used for many years as a stabilizing agent in the production of chlorinated solvents to prevent breakdown during manufacturing processes. It is also present in many household products like soaps, shampoos, baby lotion and cosmetics.
Over the past few years 1,4-Dioxane has garnered increased attention due to it’s presence in groundwater at several California locations and because there is little scientific data available on the longterm effects on human health. An additional concern is that traditional remediation technologies used for sites contaminated with chlorinated solvents are ineffective at removing 1,4-Dioxane.1
The traditional method for the analysis of 1,4-Dioxane is EPA method 8260. The high water solubility of 1,4- Dioxane causes poor purging efficiency, resulting in the relatively high reporting limits of 100 μg/L.While there is no current federal drinking water standard or maximum contaminant level, California EPA has led the nation in setting an advisory action level of 3.0 μg/L. Several different approaches have been used to achieve these lower reporting limits for 1,4-Dioxane including salting purge procedures, vacuum distillation, continuous liquid-liquid extraction, isotope dilution and selected ion monitoring.
Two of the primary problems affecting any method targeting 1,4- Dioxane are poor recovery due to high water solubility and volatility loss. Any purge and trap method is unaffected by volatility loss yet has significant problems with high water solubility. Conversely, extraction methods have problems with volatility loss due to the use of heat when continuous liquid-liquid extractors are used and again in the solvent reduction phase of the extraction.
CAS has incorporated a new method that is able to overcome both issues. The extraction procedure is based on EPA Method 3510. A 100 ml sample volume is used with the addition of 20 g NaCl. The sample is spiked with a surrogate standard, 1,4-Dioxane-d8, and extracted with methylene chloride. The extract is then dried and brought to a final volume of 5 ml. The extract is analyzed by GC/ MS running in the selected ion monitoring (SIM) mode with an ATAS Large Volume Injector (LVI). The LVI allows for a 20 μl injection.
Using the modified extraction procedure combined with large volume injection GC/MS SIM techniques, CAS reliably achieves an MRL of 0.1 μg/L. Using 1,4-Dioxane-d8 as a surrogate also ensures the performance of each analysis. For additional information on 1,4- Dioxane call Jeff Grindstaff or Lynda Huckestein at (360) 577-7222.
1.D. Grant Walson, Bruce Tunnicliffe, 1,4-Dioxane– A Little Known Compound, Environmental Science & Engineering, May ’02.