title: A spectrophotometric method for the estimation of amino groups on polymer supports.
abstract: A simple and sensitive method for the estimation of polymer-supported amino groups is reported. The polymer support is treated either with N-succinimidyl-4-O-(4,4'-dimethoxytrityl)-butyrate or 2,4-dinitrophenyl-4-O-(4,4'-dimethoxytrityl)-butyrate and a catalytic amount of 4-dimethylaminopyridine. After removal of the excess reagent through washing, a weighed quantity of the polymer support is treated with perchloric acid to release the 4,4'-dimethoxytrityl cation from the solid support into the solution. The released 4,4'-dimethoxytrityl cation, which has a strong absorption (epsilon 498 = 70,000/M) at 498 nm, is determined spectrophotometrically. A comparative study of these reagents with N-succinimidyl-3-(2-pyridyldithio)-propionate, 4,4'-dimethoxytrityl chloride, and sodium 2,4,6-trinitrobenzenesulfonate methods is also included.
authors.affiliation: DNA Synthesis Laboratory, CSIR Centre for Biochemicals, Delhi, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Gaur
authors.forename: K C
authors.initials: KC
authors.lastname: Gupta
mesh_terms: D000215:Acylation; D000588:Amines; D003432:Cross-Linking Reagents; D004247:DNA / Q000138:chemical synthesis; D004140:Dinitrophenols; D011108:Polymers; D013053:Spectrophotometry / Q000379:methods; D013388:Succinimides; D013936:Thymidine / Q000031:analogs & derivatives; D014302:Trinitrobenzenesulfonic Acid; D014320:Triphenylmethyl Compounds
chemical_list: D000588:Amines; D003432:Cross-Linking Reagents; D004140:Dinitrophenols; D011108:Polymers; D013388:Succinimides; D014320:Triphenylmethyl Compounds; C061473:N-succinimidyl-4-O-(4,4'-dimethoxytrityl)butyrate; C061474:2,4-dinitrophenyl-4-O-(4,4'-dimethoxytrityl)butyrate; C060951:5'-O-(4,4'-dimethoxytrityl)thymidine-3'-O-(2,4-dinitrophenyl) succinate; C018151:N-succinimidyl 3-(2-pyridyldithio)propionate; D014302:Trinitrobenzenesulfonic Acid; D004247:DNA; D013936:Thymidine