title: Ninhydrin reaction on thiol-reactive solid and its potential for the quantitation of D-penicillamine.
abstract: While aminothiols produce weak purple-colored reactions with ninhydrin, we demonstrate for the first time that this color could be intensely developed. Using a D-penicillamine paradigm, adsorption of this compound via a disulfide bond onto thiol-reactive solid prior to ninhydrin reaction allowed spectrophotometrical monitoring of the supernatant at 570 nm. Compared with off-solid method, this approach expanded the linear concentration range to 50-600 microg mL(-1) and enhanced the sensitivity so that D-penicillamine with the concentrations of less than 100 microg mL(-1) could be accurately quantitated by using a second-order polynomial calibration curve. Additionally, this assay was unaffected by disulfide adduct interference, highlighting its potential for the analysis of D-penicillamine as well as other aminothiols.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, Thailand. teerasak@su.ac.th
authors.forename: Theerasak
authors.initials: T
authors.lastname: Rojanarata
authors.forename: Praneet
authors.initials: P
authors.lastname: Opanasopit
authors.forename: Tanasait
authors.initials: T
authors.lastname: Ngawhirunpat
authors.forename: Choedchai
authors.initials: C
authors.lastname: Saehuan
mesh_terms: D003124:Colorimetry; D057230:Limit of Detection; D015394:Molecular Structure; D009555:Ninhydrin / Q000737:chemistry*; D010396:Penicillamine / Q000032:analysis* / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D013438:Sulfhydryl Compounds; D010396:Penicillamine; D009555:Ninhydrin