Full Description

The California Department of Health Services (CADHS) sets the reportable detectionlimits at 5 parts per trillion for 1,2,3-trichloropropane and 3 parts per billion for 1,4-dioxane. Due to the demand of low-level detection limit and poor purging efficiencyof these compounds, the existing purge and trap techniques and instrumentationcould not meet the detection requirements set by CADHS. The available liquid-liquidextraction method requires a 1L sample, 200 ml of organic solvents, and 16 hours ofreaction to extract these compounds from water matrix.The Orange County Water District (OCWD) has developed a very reliable andsensitive method without using any organic solvents and manual labor for a sampleextraction. Since 1,2,3-trichloropropane and 1,4-dioxane both are very water-solubleand volatile, the improved purge and trap techniques could separate thesecompounds. 20 minutes of purging with 40 ml/min of helium and 15 minutes ofbaking at 260 C for trap increased the purging efficiency more than 2 times. Also,the interested ions are further retrieved by multiple mass spectrometry technology,which improved the sensitivity of the system more than 50 times than normal massspectrometry. The retention time of 1,2,3-trichloropropane is 26.4 min and 17.1 minfor 1,4-dioxane. The method detection limits of 1,2,3-trichloropropane and 1,4-dioxane based on 25 ml of the sample volume are reported as 1.4 parts per trillionand 0.1 parts per billion, respectively.The improved purge and trap techniques using multiple mass spectrometry couldsave 90% of extraction time and 100% of solvent consumption compared to thecontinuous liquid-liquid extraction technique without sacrificing these detection limitsand reliability of the analysis. The developed techniques have been successfullyapplied to monitor groundwater contamination and increase the removal efficiency ofthese compounds by wastewater treatment facility using microfiltration and ultraviolet irradiation. Includes 12 references, tables.

Product Details

Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 16File Size: 1 file , 370 KB