Sediment Matrix Effects in Analysis of Pyrethroid Insecticides Using Gas Chromatography–Mass Spectrometry Dongli Wang • Jing You • Michael J. Lydy Received: 2 December 2009 / Accepted: 12 March 2010 / Published online: 26 March 2010 Ó Springer Science+Business Media, LLC 2010 Abstract In the present study, we developed a gas chromatography–quadrupole mass spectrometry method for analyzing nine pyrethroid insecticides in sediment after accelerated solvent extraction and solid phase extraction cleanup. The operation was optimized, and negative chemical ionization was selected to improve analytical selectivity. The sediment matrix effects on qualification were evaluated, and matrix-matched standard solutions, along with the internal standard calibration, were used to reduce the matrix-induced chromatographic response enhancement. The method detection limits were 0.68 to 1.43 lg/kg dry weight (dw), and recoveries were 70.3 to 143.3%, 61.1 to 169.7%, and 65.7 to 118.8%, with relative SDs of 4.2% to 32.1%, 4.9 to 23.6%, and 1.5 to 23.3% at the spiked levels of 1.0, 5.0 and 20 lg/kg dw, respectively. The method was also validated by measuring pyrethroids in field-contaminated sediment samples collected in central California and southern Illinois. Pyrethroid insecticides are gradually becoming the pre- dominant insecticides used for agricultural and urban applications, which has resulted in aqueous contamination in these areas (Weston et al. 2004, 2005; Amweg et al. 2006; Holmes et al. 2008). Due to their low water solu- bility, pyrethroids bind to sediment particles, and can induce adverse effects to benthic species at extremely low concentrations (Moore and Waring 2001; Amweg et al. 2005; Maul et al. 2008). Improving analytical sensitivity and selectivity is important for quantifying trace pyre- throids in complicated sediment matrices. By providing better identification information to avoid positive errors, gas chromatography–mass spectrometry (GC/MS) has increased analytical selectivity compared with GC/electron capture detector (GC/ECD), and several types of GC/MS techniques have been used for pyrethroid analysis. GC coupled with high-resolution mass spec- trometry (GC-HRMS) could simultaneously analyze pyre- throids, pyrethrins, and piperonyl butoxide in sediment (Woudneh and Oros 2006), but high maintenance costs and the need for a specialized technician to operate the instrument limited its wide application. Bench-top GC/MS instruments, including GC–ion trap MS (GC/ITMS) and GC–quadrupole MS (GC/q-MS), have also been used for pyrethroid analysis (Valsamaki et al. 2007; Mekebri et al. 2008; Miranda et al. 2008; Smalling and Kuivila 2008; You et al. 2010). Smalling and Kuivila (2008) reported a mul- tiresidue method to analyze 85 current-use and legacy pesticides, which included 14 pyrethroids in bed and sus- pended sediments, using GC/ITMS. The GC/q-MS oper- ated in electron impact (EI) or negative chemical ionization (NCI) mode was used for the analysis of synthetic pyre- throid insecticides in soil, fish tissue (Valsamaki et al. 2007) and sediment (Miranda et al. 2008) as well. In addition to improving sensitivity and selectivity, decreasing matrix effects is critical for accurate measure- ments. Matrix-induced chromatographic response enhance- ment and isomerization have been reported during the D. Wang Á M. J. Lydy Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, 171 Life Science II, Carbondale, IL 62901, USA J. You (&) State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China e-mail: youjing@gig.ac.cn 123 Arch Environ Contam Toxicol (2010) 59:382–392 DOI 10.1007/s00244-010-9506-5