In Situ Derivatization/Solid-Phase Microextraction for the Determination of Haloacetic Acids in Water

Abstract

An in situ derivatization solid-phase microextraction method has been developed for the determination of haloacetic acids (HAAs) in water. The analytical procedure involves derivatization of HAAs to their methyl esters with dimethyl sulfate, headspace sampling using solid-phase microextraction (SPME), and gas chromatography-ion trap mass spectrometry (GC/ITMS) determination. Parameters affecting both derivatization efficiency and head-space SPME procedure, such as the selection of the SPME coating, derivatization-extraction time and temperature, and ionic strength, were optimized. The commercially available Carboxen-poly(dimethylsiloxane) (CAR-PDMS) fiber appears to be the most suitable for the determination of HAAs. Moreover, the formation of HAA methyl esters was dramatically improved (up to 90-fold) by the addition of tetrabutylammonium hydrogen sulfate (4.7 micromol) to the sample as ion-pairing agent in the derivatization step. The precision of the in situ derivatization/HS-SPME/GC/ITMS method evaluated using an internal standard gave relative standard deviations (RSDs) between 6.3 and 11.4%. The method was linear over 2 orders of magnitude, and detection limits were compound-dependent, but ranged from 10 to 450 ng/L. The method was compared with the EPA method 552.2 for the analysis of HAAs in various water samples, and good agreement was obtained. Consequently, in situ derivatization/HS-SPME/GC/ITMS is proposed for the analysis of HAAs in water.

Hyphenated Techniques in Gas Chromatography

“…One of the significant advantages of ion traps compared to the above-mentioned linear quadrupole mass analysers is their high sensitivity in full scan mode. Based on this, many qualitative and quantitative applications have been reported (Allchin et al, 1999& Sarrion et al, 2000. Beside the conventional full scan mode of operation, an important advancement by application of ion trap in GC-MS has been the capability of an ion trap mass analyser to perform tandem mass spectrometric investigations of ions of interest in collision-induced dissociation (CID) for ion structure elucidation (Plomley et al, 2000) (see the text below for tandem mass spectrometers).…”

A review of analytical methods for the determination of trichloroethylene and its major metabolites chloral hydrate, trichloroacetic acid and dichloroacetic acid

“…All of the methods using ion trap mass spectrometers described in this paper are coupled to GCs. These methods were developed for the analysis of TCE in drinking water (Eichelberger et al, 1990;Bocchini et al, 1999;Sarríon et al, 1999), HAAs in water (Sarríon et al, 1999(Sarríon et al, , 2000 and HAAs in plasma, urine, and water (Jia et al, 2003).…”

“…Several methods using SPME are discussed in this paper for the analysis of TCE in biological samples (Dehon et al, 2000;Xu et al, 1996;Dixon et al, 2005), HAAs in drinking water (Sarríon et al, 1999(Sarríon et al, , 2000Wu et al, 2002;Gabryelski et al, 2003), and HAAs in biological samples (Dehon et al, 2000). PDMS fibers were used for each TCE study (Dehon et al, 2000;Xu et al, 1996;Dixon et al, 2005) and three of the HAA studies (Sarríon et al, 1999;Wu et al, 2002;Gabryelski et al, 2003).…”

“…PDMS fibers were used for each TCE study (Dehon et al, 2000;Xu et al, 1996;Dixon et al, 2005) and three of the HAA studies (Sarríon et al, 1999;Wu et al, 2002;Gabryelski et al, 2003). In another HAA study using SPME fibers, five types of SPME fibers were tested (Sarríon et al, 2000). The five types of fibers (and each fiber thickness) tested were PDMS (polydimethylsiloxane, 100 µm), PA (polyacrylite, 85 µm), CAR-PDMS (carboxen-polydimethylsiloxane, 75 µm), PDMS-DVB (polydimethylsiloxane-divinylbenzene, 65 µm), DVB-CAR-PDMS (StableFlex divinylbenzene-carboxenpolydimethylsiloxane, 50/30 µm).…”

“…The CAR-PDMS had the highest extraction efficiency for DCA, TCA and all of the other HAAs analyzed. Several of the SPME methods discussed optimization of the SPME for a particular analyte(s) (Xu et al, 1996;Sarríon et al, 2000;Wu et al, 2002;Dixon et al, 2005), and an SPME theory paper (Pawliszyn, 2000) describes the in-depth details of SPME.…”