Talanta 81 (2010) 1034–1039 Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Development of a simple desulfurization procedure for the determination of butyltins in complex sediment samples using gas chromatography–pulsed flame photometric detection M. Bravo ∗ , A. Valenzuela, W. Quiroz, M. Pinto, M. Flores, H. Pinochet Laboratorio de Química Analítica y Ambiental, Instituto de Química, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2950, Valparaíso, Chile article info Article history: Received 23 October 2009 Received in revised form 27 January 2010 Accepted 27 January 2010 Available online 4 February 2010 Keywords: Desulfurization Organotin compounds Gas chromatography–pulsed flame photometric detection (GC–PFPD) Sediments abstract In this study a rapid solid phase extraction (SPE) procedure was developed to minimize the effect of different sulfur species for the determination of butyltin in sediments. The organosulfur species and organotins were firstly retained on C8 cartridges and then organotins were selectively eluted and analyzed by gas chromatography–pulsed flame photometric detection (GC–PFPD). Optimal conditions for the SPE procedure were obtained using an experimental design approach. The method’s accuracy was established by analyzing a certified reference material (CRM), BCR-646 freshwater sediment. The experimental values were found to be in agreement with the assigned values for butyltins. Finally, complex sediment samples collected from a Chilean harbor were analyzed using this methodology to demonstrate its analytical potential for the determination of butyltin in environmental samples. © 2010 Elsevier B.V. All rights reserved. 1. Introduction The use of organotin compounds (OTC) as fungicides, insecti- cides, bactericides, wood preservatives and PVC stabilizers has led to their release into the environment, resulting in the contamina- tion of aquatic and terrestrial ecosystems [1,2]. Since the toxicity of OTC depends on the nature and the number of organic groups bonded to the tin atom, many analytical pro- cedures have been developed for the determination of organotin in various environmental samples [3,4]. Species selective analysis of organotins is performed using a combination of a chromato- graphic separation, preferably gas chromatography (GC), with a sensitive and selective detection method. The pulsed flame photo- metric detector (PFPD) is both sensitive and selective and appears to be the best choice for analysis, especially in routine analysis because of its low cost and reduced consumption of gases [5,6].A speciation procedure for the simultaneous determination of butyl, phenyl and octyltins involving sodium tetraethylborate (NaBEt 4 ) derivatization and GC-PFPD has been developed and validated for the analysis of environmental samples [7], such as sediments [8], sewage sludge [9] and plants [10], with satisfactory results. Unfortunately, sulfur interference has been reported in the analysis of sulfur-rich sediment samples when flame photometric ∗ Corresponding author. Tel.: +56 32 2273168; fax: +56 32 2273422. E-mail address: manuel.bravo@ucv.cl (M. Bravo). detector (FPD) or PFPD are used [11,12]. It is known that elemental sulfur in sediments is co-extracted with OTC and alkylated in the derivatization step prior to GC determination, which leads to the formation of dialkylated mono-, di- and trisulfides [13,14]. Atom selective detectors coupled with GC eliminate such sulfur interfer- ences due to their high selectivity. However, the injection of large amounts of sulfur species can overload the stationary phase and shift the retention time, which results in the misinterpretation of data [11]. Therefore, an effective method to eliminate sulfur and organosulfur compounds is mandatory for accurate OTC determi- nation. Several procedures have been proposed for sulfur and organosulfur compound elimination during OTC determination in sediments when using GC [4]. Common approaches, such as irreversible adsorption of sulfur compounds on activated copper or aluminum oxide and desulfurization using tetrabutylammo- nium sulfite, can be used to eliminate elemental sulfur, however, organosulfur compounds cannot be quantitatively removed from extracts [4,15]. Alternative approaches, evaluated by applying laborious and time consuming Grignard alkylations, result in the satisfactory elimination of alkylsulfides, but alkylated phenyltins are irreversibly adsorbed [15]. Few studies have been conducted based on similar procedures for well established derivatization using NaBEt 4 . Some cleanup procedures that employ Florisil or Alumina sorbent to eliminate the organic material or pro- teins after an ethylation step have been applied for sediment [16] and biological samples analyses [17,18]. However, these 0039-9140/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.talanta.2010.01.056