Kinetic spectrophotometric determination of thiols and ascorbic acid

This paper describes a kinetic spectrophotometric method for the determination of L-ascorbic acid (AA) and thiols (RSH). Absorbance of Fe(II)-phen complex formed during the reaction of AA or RSH with Fe(III)-phen was continuously measured at 510 nm by double- beam spectrophotometer with flow cell. For determination some thiols, the catalytic effect of Cu2+ ions was used. AA and RSH can be determined in concentration ranges from 4.0 x 10(-6) to 4.0 x 10(-5) Mand from 8.0 x 10(-6) to 8.0 x 10(-5) M, respectively. The applicability of the proposed method was demonstrated by determination of chosen compounds in pharmaceutical dosage forms.