Spectrophotometric and spectrofluorimetric determination of cycloserine with p-benzoquinone
Abstract
Spectrophotometric and spectrofluorimetric methods are described for the determination of cycloserine. Both methods are based on the reaction of cycloserine in aqueous solution of pH 8.2 with p-benzoquinone. A fluorescent compound with an absorption maximum (and also an excitation maximum) at 381 nm is obtained. The complex has an apparent molar absorptivity of 4.76 × 103 l mol–1 cm–1 and Beer's law is obeyed over the range 4–20 µg ml–1. The emission maximum of the complex is at 502 nm. The fluorescence intensity is linearly related to concentration over the range 0.04–0.2 µg ml–1. When applied to capsules labelled to contain 250 mg, the proposed methods gave mean recoveries of 100.97 ± 1.14 and 99.8 ± 1.13%, respectively.