The technique of solid phase microextraction (SPME) was used for the extraction of halogenated contaminants of water samples from three cities of the State of São Paulo and the extracts were submitted to gas chromatographic analysis with electron capture detection (GC-ECD). In the samples of water collected at the city of São Paulo the detected level of trihalomethanes (THM) expressed as the sum of chloroform, dibromochloromethane and dichlorobromomethane, were higher than the permissible limit established by the Brazilian regulation. In the samples collected at the two other cities the level of any of the three THM remained below the sensitivity of the ECD.

Foi estudada a independência da resposta de um Detector por Emissão Atômica Induzida em Plasma de Microondas utilizando-se nove compostos organoclorados como amostra de teste. Com ajuste apropriado das condições operacionais do equipamento, monitorando os sinais na linha de emissão do cloro em 479,5 nm, para os nove compostos foram obtidas respostas concordantes ao nível de 8,5% ou menos, o que é adequado para uso do método de calibração independente do composto. Propõe-se que a confiabilidade da quantificação com a metodologia de calibração independente do composto pode ser melhorada, se um conjunto de compostos é usado em lugar de um único composto de calibração.

The independence of the response of a Microwave Induced Plasma Atomic Emission Detector (GC-MIP) for Gas Chromatography with the chemical structure of the analyte has been exploited using as teste samples nine organochlorine compounds. With signal monitoring at the chlorine 479.5 nm emission line and after proper adjustment of the operational conditions of the GC-MIP the agreement of the detector response for the nine compounds was of 8.5% or less, which is adequate for the use of the compound-independent calibration method. It is proposed that the reliability of the quantitation after applying the compound-independent calibration methodology may be enhanced if a set of calibration compounds is used instead of a single calibration compound.