Quick cuvette test for thiol compounds

Plastic cuvettes coated chemically with Prussian Blue films were investigat ed as quick disposable spectrophotometric test for mercapto-compounds. The determination is based on discoloration of the coating film due to its redu ction by analyte. The changes of film absorbance were measured at 720 nm. I t was found that the cuvettes can be used for selective determination of cy steamine, beta-mercaptoethanol and L-cysteine in millimolar ranges of conce ntration. The test is useful for determination of L-cysteine and N-acetylcy steine in pharmaceutical products.