EPA scrutinizing 1,4-dioxane

The compound 1,4-dioxane is receiving increased attention from regulating authorities throughout the U.S. It was developed as a stabilizer compound to enhance solvent life and prevent decomposition from light, heat, oxygen, and acids and is listed by the EPA as a Class B2 probable carcinogen. Solvents such as trichloroethane (TCA) contain 1,4-dioxane and have been used in metal cleaning, degreasing, electronics, and many other applications. 1,4-dioxane is also used as a solvent in lacquers, paints, oils, and plastics. (See EPA 749-F-95-010a.) Chemist Jason Long performs 1,4 dioxane analyses by Purge and Trap GC/MS, using isotope dilution and SIM to achieve regulatory limits. Although 1,4-dioxane is listed as a volatile compound in SW-846 8260B and in the Appendix IX list of compounds, EPA has not included it in the Target Compound List (TCL) or Priority Pollutant List (PPL). Thus, site investigations and remedial designs may have failed to account for its presence. The EPA has not yet established Maximum Contaminant Levels (MCL) for 1,4-dioxane but has issued a health-based advisory level of 3 µg/L for drinking water. Project-specific limits may be as low as: California 3 µg/L Florida 5 µg/L North Carolina 7 µg/L Massachusetts 50 µg/L Maine 70 µg/L Due to the high solubility and polarity of 1,4-dioxane, typical GC/MS 8260B achieves a method detection limit (MDL) of 70 µg/L, Limit of Quantitation (LOQ) of 250 ug/L, and relative response factor (RRF) of 0.008. This may be acceptable for specific applications; however, to achieve the highest data quality and sensitivity available for 1,4-dioxane, Lancaster Laboratories’ GC/MS groups offer several options: SW-846 8270C This method consists of solvent extraction and GC/MS analysis. It provides the economic benefit that 1,4-dioxane can be added to any Semivolatile Base Neutral analysis at no additional charge. It achieves: MDL 1 µg/L LOQ 3 µg/L RRF 0.75 SW-846 8260B Selected Ion Monitoring (SIM) This GC/MS purge-and-trap method offers improved sensitivity and response by setting the detector to SIM mode and utilizing a 1,4-dioxane-d8 internal standard. This analysis method can achieve: MDL 0.5 µg/L LOQ 2 µg/L RRF ~1 For more information on 1,4-dioxane and other technical topics please visit www.lancasterlabs.com/environmental/techlit.htm (Environmental technical literature) or contact environmental business development at (717) 656-2300.