Applications of FIA in pharmaceutical analysis

A FIA method for the determination of captopril was based on the oxidation of the thiol group in the molecule by Ce . This reaction results in the emission of light (chemiluminescence), which can be measured. In this example the dye rhodamine G was used to enhance the emission of light by the reaction. The method developed was rapid and precise.  

Diclofenac sodium, famotidine and ketorolac were analysed utilising their formation of a coloured charge transfer complex with 2,4 dichloro-6-nitrophenol. The complexes were detected by UV/visible spectrophotometry at 450 nm. The method was not affected by the presence of common excipients in the formulations analysed. The precision and accuracy of the method was comparable to that of HPLC methods used to analyse the same samples.  

The generation of a eoloured product upon the oxidation of promethazine with Ce was used in the development of a FIA method. Promethazine in tablet form could be analysed by this method with a precision of + 1% and at a rate of 122 samples per h. In a similar method promazine was oxidised by passing through a short column containing Mn02 and then the oxidation product was measured.  

Chlorocresol is a preservative commonly used in injections and its determination often involves the use of laborious extraction procedures in order to separate it from formulation components, followed by spectrophotometric measurement. A FIA method for chlorocresol was developed by utilising its reaction with nitrous acid to form a coloured nitro compound. The method was accurate to 99.5% of the true value of chlorocresol in a formulation and a precision of 1% was achieved.  

FIA system used to analyse heavy metal residues by extraction of their complexes with DDC into carbon tetrachloride. 

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