Determination of heparin using flow injection analysis with spectrophotometric detection Original Research Article

A study has been made of the conditions for the reaction of heparin with thiazine dyes in both static and flow-through systems. Factorial design was used to determine the significance of the individual flow-through experimental parameters and their optimal values were found: at pH = 6, cdye = 8 × 10−5 mol l−1, the optimum overall flow rate (dye : buffer = 1 : 1) is of 4.2 ml min−1, volume injected of 500 μl, reaction coil length of 20 cm. Methods were developed for the flow-through spectrophotometric determination of heparin. The concentration ranges of calibration curves are 0–10 and 0–12 μg ml−1, respectively, for individual dyes, the limit of detection of about 0.1, limit of determination of about 0.3 μg ml−1.