Determination of Organic Compounds in Drinking Water by Liquid-Solid Extraction and Capillary Column Gas Chromatography/Mass Spectrometry
This method is for the determination of semivolatile organic compounds (SVOCs) in finished drinking water, source water, or drinking water in any treatment stage. This method is applicable to a wide range of organic compounds that are efficiently partitioned from the water sample onto a Carbon-18 organic phase chemically bonded to a solid matrix in a disk or cartridge, and sufficiently volatile and thermally stable for gas chromatography.
SVOC's are extracted from a water sample using liquid-soild extraction (LSE). One L of sample is passed through a cartridge or disk containing a solid matrix with a chemically bonded Carbon-18 organic phase. The organic compounds are eluted from the LSE cartridge or disk with small quantities of ethyl acetate followed by methylene chloride, the extract is concentrated and an aliquote is injected into a high resolution fused silica capillary column of a gas chromatography/mass spectrometry (GC/MS) system.
Sample collection equipment includins samplers and tubing should be free of plastic parts which may leach interfering anlaytes into the water.
Addition of the preservatives sodium sulfite and HCl to the sample bottles prior to shipping to the sampling site is not allowed by the method. The preservation needs to be done at the time of sample collection.
Note: Typical holding times are 14 days from sample collection to extraction. However, if the following analytes are to be determined, the samples cannot be held for 14 days and must be extracted immediately after collection and preservation: carboxin, diazinon,disulfoton, disulfoton sulfoxide, fenamiphos, and terbufos. If cyanizine is to be determined, a separate sample must be collected.
(EPA: Office of Water)