Journal of Chromatography A, 859 (1999) 193–201 www.elsevier.com / locate / chroma Analysis of some pesticides in water samples using solid-phase microextraction–gas chromatography with different mass spectrometric techniques * Marco Natangelo , Simona Tavazzi, Roberto Fanelli, Emilio Benfenati Department of Environmental Health, Istituto di Ricerche Farmacologiche ‘‘ Mario Negri’’, Via Eritrea 62, 20157 Milan, Italy Received 2 March 1999; received in revised form 3 August 1999; accepted 4 August 1999 Abstract A solid-phase microextraction (SPME)–GC procedure has been developed for the analysis of four selected pesticides (propanil, acetochlor, myclobutanil and fenoxycarb) in water samples. Mass spectrometry (MS) was used and two different instruments, a quadrupole MS system and an ion trap operating in the MS–MS mode, were compared. A Carbowax– divinylbenzene SPME fiber was used. The performances of the two GC–MS instruments were comparable in terms of linearity (in the range of 0.1–10 mg/l in water samples) and sensitivity (limits of detection were in the low ng/l range); the quadrupole MS instrument gave better precision than the ion trap MS–MS system, but generally the relative standard deviations for replicates were acceptable for both instruments (,15%). Specificity with these two instruments was comparable in the analysis of ground water samples. Recovery tests were made to assess the applicability of the SPME procedure in the quantitative analysis of contaminated groundwaters.  1999 Elsevier Science B.V. All rights reserved. Keywords: Water analysis; Environmental analysis; Pesticides 1. Introduction great demand for high-sensitivity methods for this topic, on account of the 0.1 mg / l admissible level for Solid phase microextraction (SPME) is a recent pesticides in water in the European Union (EU) [2]. sample preparation technique that is proving increas- Gas chromatography–mass spectrometry (GC–MS) ing useful in organic analytical chemistry [1]. The has been widely applied [3,4], because of its high device is simple and easy to use, with expanding specificity and sensitivity and for the potential of possibilities for the analysis of liquid samples. The multiresidue and multiclass analyses. option of extracting the sample and injecting the SPME has been introduced for pesticide analysis adsorbed analytes into the analytical instrument in water samples [5–9], and GC–MS has been using the same device is particularly useful when recently used together with this technique to detect monitoring pesticide pollution in water. There is a pesticides in waters [10–14]; method validations in inter-laboratory tests have been also done [15,16], demonstrating the wide applicability of the SPME *Corresponding author. Tel.: 139-2-390-141; fax: 139-2-3900- technology in this field. 1916. E-mail address: natangelo@irfmn.mnegri.it (M. Natangelo) Another attractive technique for pesticide detec- 0021-9673 / 99 / $ – see front matter  1999 Elsevier Science B.V. All rights reserved. PII: S0021-9673(99)00850-X