Quantitative determinations in conventional flow injection analysis based on different chemometric calibration statregies: a review

This paper shows the possibilities of chemometric techniques for enhancing the analytical capabilities of conventional flow injection analysis (FIA). FIA is an excellent methodology for generating responses of different complexity from which relevant analytical information can be extracted chemometrically. The simplest case involves a single scalar datum per sample, as commonly occurs with FI peak heights or areas. More complex multivariate data consist of data vectors or matrices generated by taking a time array over the FI peak at a certain wavelength, or by recording the whole spectrum at a pre-selected time or at regular steps over the peak. The calibration procedures that can be applied to each type of data (i.e. scalars, vectors or matrices) in order to quantify the analyte in unknown samples are generically called zero-, first- and second-order calibration methods, respectively. The characteristics, advantages and shortcomings of each type of calibration are illustrated from various examples of quantitative determinations of amines and amino acids using 1,2naphthoquinone-4-sulfonate as a derivatizing reagent. In addition, other FI methods using multivariate calibration procedures are also reviewed.