Flow-injection analysis systems with immobilized enzymes. Improvement of applicability by integration of coupled reactions, separation steps and background correction

The specificity of enzymes is often not sufficient to simultaneously determine two parent substrates in a given matrix. Approaches to enhance the selectivity by applying the principle of an array arrangement to flow-injection analysis (FIA) systems based on several immobilized isoenzymes are successful. Immobilized enzymes and detectors in FIA systems often suffer from interferences from impurities of the matrix. Examples are given which prove that this problem can be overcome by an integrated preseparation of the analyte (pervaporation, electrodialysis) or by correction of the matrix signal based on background subtraction using computerized data accumulation and processing.