The Determination of DBPs Using a Solid-Phase Microextraction (SPME)-GC/ECD Technique

摘要

Work was undertaken to develop an analytical technique for the determination of several classesof disinfection by-products (DBPs), which was amenable to a wide range of compounds with highsensitivity. A solid-phase microextraction (SPME)-gas chromatography/electron capture detector(GC/ECD) technique was developed and used in conjunction with several other analyticalmethods (i.e., solid-phase extraction [SPE]-GC/mass spectrometry [MS], purge-and-trap [P&T]-GC/MS, and liquid-liquid extraction [LLE]-GC/ECD). These methods were used to investigatethe occurrence of DBPs at 12 water treatment plants in the U.S.The SPME-GC/ECD technique is simple and eliminates the need for solvents and the complicatedsteps necessary for analyzing for semivolatile DBP. This technique has been automated and hasreduced sample preparation time. Development of this method included investigating varioustypes of SPME fibers, adsorption and desorption times, injector/desorption temperatures,headspace versus direct extraction techniques, and the use of an internal standard. The methoddeveloped here samples the headspace of a 5-mL sample, which has the addition of sodiumchloride (25 percent by weight), with a Carboxen/divinylbenzene/polydimethylsiloxane(CAR/DVB/PDMS) fiber. A 30-min adsorption time and a 5-min desorption in a 200°C injectorgave the best results for analyzing for the target DBPs. Most, if not all, of the analytes can bedetected below 1.0 μg/L.