Determination of endosulfan and its metabolites in human urine using gas chromatography–tandem mass spectrometry1

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Abstract

A method was developed for determining the occupational exposure to endosulfan and its main metabolites (endosulfan-ether, -lactone and -sulfate) in human urine using dieldrin as an internal standard. Solid phase extraction (SPE) and gas chromatography–tandem mass spectrometry (GC–MS–MS) have been used due to their high sensitivity and selectivity in avoiding most matrix interferences. The recovery efficiencies of the tested compounds yielded more than 89.2 % at the fortification level of 10 ng ml−1 in urine and their relative standard deviations were between 9.1 and 12.8 %. The detection limit of each compound ranged between 6 and 18 pg ml−1. Urine samples from nine pest control operators were analysed and total endosulfan concentrations between 94 and 2038 pg ml−1 were found.

Introduction

Endosulfan ((1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-en-2,3-ylenebismethylene) sulfite) is a chlorinated insecticide used in many countries. It is liposoluble and persistent in the environment [1]. In the technical grade, endosulfan contains two stereoisomers: α- and β-endosulfan (α- and β-end). It is rapidly metabolised and excreted in the urine and feces as oxidation products like endosulfan-sulfate (end-sulfate), -alcohol (end-alcohol), -ether (end-ether) or -lactone (end-lactone) resulting from the cleavage of the cyclic sulfite group. Endosulfan penetrates the intact skin and is also absorbed by inhalation and from the gastrointestinal tract [2], [3], [4], [5].

Endosulfan has shown estrogenic effects on humans [6], [7]. For mammals it presents a moderate toxicity and is highly toxic to fish and some bird species. This insecticide has been analysed in natural waters [8], greenhouse air [9], fish [10], human milk [11], meat [12] and sediments [13], most of them using GC–ECD but there is no reported method for the analysis of endosulfan and its metabolites in human urine.

Previous experiments carried out [9] showed that endosulfan can be successfully sampled in air using polyurethane foam (PUF). Dissipation processes of endosulfan indicate that 24 h after application in the greenhouse, 7.5 % of the initial concentration remained in the greenhouse atmosphere. The dissipation and decline process may be influenced by parameters such as vapour pressure, temperature and relative humidity or the presence of volatile organic solvents in emulsifiable concentrates as in endosulfan formulations.

In this paper a method is proposed for determining endosulfan and its main metabolites in human urine using solid phase extraction (SPE) and gas chromatography–tandem mass spectrometry (GC–MS–MS) which are both very sensitive and selective. The results obtained from an analysis of urine samples from agricultural workers in Almerı́a (Spain) are reported.

Section snippets

Chemicals

Pesticide grade n-hexane, diethyl ether and methanol from Merck (Darmstadt, Germany) were used. Organic free water was prepared by distillation and then by Milli-Q SP treatment (Millipore Corporation, USA).

Pesticide analytical standard materials were purchased from Riedel-de-Haën (Seelze-Hannover, Germany) with purities higher than 99 %.

Stock solutions of individual pesticides at 400 μg ml−1 were prepared in n-hexane and stored in a freezer (−30°C). The standard working solutions were obtained

Instrumental variables

The gas chromatographic conditions yielded a satisfactory separation of the analytes. The retention times for the insecticide and its metabolites in these chromatographic conditions are 7.07 min (end-ether), 8.48 min (end-lactone), 9.22 min (α-end), 9.75 min (dieldrin, internal standard), 10.44 min (β-end) and 11.30 min (end-sulfate). Less than 12 min were required for an adequate separation of all the compounds. For the mass spectrometer detector, Automatic Gain Control (AGC) was switched on

Conclusions

A fast and accurate method with high sensitivity is reported for the occupational analysis of endosulfan and its metabolites in human urine. Solid phase extraction and GC–MS–MS have proven their selectivity in that they avoid most of the interferences from the matrix. Urine samples from nine pest control operators were analysed and total concentrations of pesticide and metabolites that ranged between 94 and 2038 pg ml−1 were found.

Acknowledgements

This research was supported by the European Union (Project SMT4-CJ96-2048 (DG-12-RSMT)) and by the Comisión Interministerial de Ciencia y Tecnologı́a (C.I.C.Y.T.) (Project AMB97-1194-CE).

References (13)

  • J.L. Martı́nez Vidal et al.

    J. Chromatogr. A

    (1997)
  • A. Herrera et al.

    J. Food Protection

    (1994)
  • C.R. Worthing, The Pesticide Manual. A Worked Compendium, 7th ed., British Crop Protection Council. London, UK, 1983,...
  • H. Aizawa, Metabolic Maps of Pesticides, Academic Press, Inc. Orlando, FL, USA, 1982, p....
  • E. Astolfi, Environmental Health Criteria for Endosulfan, World Health Organisation, Geneva, Switzerland,...
  • C.M. Menzie, Metabolism of Pesticides. Update II. United States Department of the Interior Fish and Wildlife Service,...
There are more references available in the full text version of this article.

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1

This article is dedicated to Dr. Antonio Arrebola Ramı́rez of the University of Granada, in memoriam.

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