Usefulness of a detector inlet overpressure and stream splitting in FIA systems to deal with food sample pre-treatment requirements. Application to wine analysis

Abstract

The use of stream splitting to obtain high sampling rate flow injection analysis (FIA) large dispersion manifolds to deal with pre-treatment requirements in the analysis of food components with a high concentration is described. This procedure is illustrated in the FIA determination of calcium using an atomic absorption detector and in the colorimetric determination of phosphate in wines. These manifolds proved to be an advantageous alternative to those including mixing chambers and diluters, as they are simpler and provide higher sampling rates (60–240 samples h −1 are achieved). Also described here is the use of an overpressure at the entrance to the atomic absorption nebulizer to minimize matrix physical interferences, by presenting the results obtained for the FIA—atomic absorption copper determination in wines. The results obtained for several wine samples by the developed FIA methodologies were in good agreement with those provided by the reference methods.