Desenvolvimento e avaliação de metodos cromatograficos para compostos do tipo CxCLyBrzHn

AUTOR(ES)
DATA DE PUBLICAÇÃO

1994

RESUMO

Chromatographic methods for qualitative and quantitative analysis of brominated and/or chlorinated compounds, hydrogenated or not, were developed and evaluated. For the non-hydrogenated compounds, linear relations between the Retention Time and the number of bromine atoms established two classes of compounds: CBrxCly and C2BrxCly (x + y = 4); which were used to identify several compounds. Quantitative parameters were determined using a Flame Ionization Detector (FID). Those determined for the Internal Standardization Method (ISM) are characteristic of the compounds and may be used to enhance the reliability of the identifications. In the quantitative work we also used the External Standardization Method (ESM). The ESM permits the use of analytical interpolations from linear equations for the Area X Mass relations. For the ISM the Area Ratio X Mass Ratio (Ra X Rm) is strongly dependent on the sample concentration and this dependence is more pronounced for the individual compounds than for their mixtures. We propose a concentration effect that could be explained in terms of deactivation of active sites of the packing by one of the components of the mixtures. We also observed that for some compounds the Ra X Rm curve is not linear, which could be explained in terms of a non-linear relation between sample and internal standard response factors. For the hydrogenated compounds both linear and non-linear relations of retention parameters to specific properties were observed, resulting four classes: BrxC4-x, nBr - Cx. Br(CH2)nBr and Brx-C3. Within the first two classes the retention correlatios are linear allowing tentative identification of the compounds. For the quantitative study the ISM applied to four of the compounds representing each of the described classes showed that this method is adequate for quantification. Three of the compounds have linear Ra X Rm behaviour and the one which is non-linear has a well defined behaviour for graphic interpolations. We conclude that the ISM is the most suitable for the quantitative analysis, although when Ra X Rm is not linear it is necessary to use graphic interpolations, since defining the ESM requires too many data, making the method tedious and not practical. Other relationships which were derived for these compounds should also be applied to enhance the reliability of the quantitative data.

ASSUNTO(S)

analise cromatografica quimica analitica qualitativa

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