Ninhydrin reaction on thiol-reactive solid and its potential for the quantitation of D-penicillamine.
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.
Rojanarata
Theerasak
T
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, Thailand. teerasak@su.ac.th
Opanasopit
Praneet
P
Ngawhirunpat
Tanasait
T
Saehuan
Choedchai
C
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*
D013438:Sulfhydryl Compounds; D010396:Penicillamine; D009555:Ninhydrin