Determinação multirresiduos de pesticidas em agua por cromatografia liquida de alta eficiencia com enfase em detecção por espectrometria de massas e novos sorventes para extração em fase solida

AUTOR(ES)

Sonia Claudia do Nascimento de Queiroz

DATA DE PUBLICAÇÃO

2001

RESUMO

A multiresidue method for determination of pesticides in water samples was developed. The following pesticides were studied: 2,4-D, linuron, diuron, atrazine, ametryn, tebuthiuron, simazine, dimethoate, carbendazim, carbaryl and 3,4-DCA. Two methods of extraction and preconcentration were compared: liquid-liquid extraction (LLE) and solid-phase extraction (SPE). The pesticides were analysed by liquid chromatography coupled with mass spectrometry .The separation was carried-out using a reversed phase C-18 analytical column with gradient elution. LLE was shown to be suitable as an extraction and preconcentration technique, except for carbendazim; while SPE, using the copolymer styrene-divinylbenzene (Supelclean Envi-chrom P), was suitable for the pesticide extraction, except for linuron. The methodology was validated and limits of detection at 0.1 mg/L or lower were obtained, except for 3,4-DCA and 2,4-D. The LC/MS procedure was robust and good detectibility and selectivity was obtained for routine analysis. New reversed-phase sorbents, C-8 e C-18, for SPE were developed. These were obtained by depositing polysiloxanes (polymethyloctylsiloxane-PMOS or polymethyloctadecylsiloxane- PMODS) onto silica, with immobilization using different process: gamma irradiation, microwave and temperature. These sorbents were characterizated by elemental analysis, infrared spectroscopy, scanning electron microscopy and termogravimetric analysis. The breakthrough volumes for benomyl, tebuthiuron, simazine, atrazine, diuron e ametryn were estimated. These sorbents were applied in analysis of pesticides in water samples in both the on-line and off-line modes and in urine. The performance of these sorbents was at least as good as that of commercial cartridges.

ASSUNTO(S)

sorventes extração (quimica) pesticidas cromatografia liquida

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