title: Study of 2-(2-quinolinylazo)-5-dimethylaminobenzoic acid as a new chromogenic reagent for the spectrophotometric determination of cobalt.
abstract: 2-(2-Quinolinylazo)-5-dimethylaminobenzoic acid (QADMAB) is proposed as a new sensitive and selective chromogenic reagent for spectrophotometric determination of cobalt. The QADMAB reacts with cobalt in the presence of cetyl trimethylammonium bromide (CTMAB) medium to form a violet complex of molar ratio 1:2 (cobalt to QADMAB) in the pH range 3.2-5.2. The molar absorptivity of the complex is 1.28x10(5) L mol(-1) cm(-1) at 625 nm. Beer's law is obeyed in range 0.01-0.32 micro g mL(-1). The relative standard deviation for eleven replicate samples of 0.2 micro g mL(-1) is 0.76%. This method was applied to the determination of cobalt in biological samples, Vitamin B(12), alloys and water with good results.
authors.affiliation: Key Laboratory of Chemistry and Engineering, Yunnan Academy of Tobacco Science, Kunming 650106, PR China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Li
authors.forename: Yang
authors.initials: Y
authors.lastname: Guanyu
authors.forename: Baoxing
authors.initials: B
authors.lastname: Wang
authors.forename: Ciqing
authors.initials: C
authors.lastname: Jiang
authors.forename: Giayuang
authors.initials: G
authors.lastname: Yin
mesh_terms: D001565:Benzoates / Q000737:chemistry*; D002863:Chromogenic Compounds / Q000737:chemistry*; D003035:Cobalt / Q000032:analysis*; D006197:Hair / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011804:Quinolines / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods*; D013662:Tea / Q000737:chemistry; D014026:Nicotiana / Q000737:chemistry; D014805:Vitamin B 12 / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis; D062367:ortho-Aminobenzoates
chemical_list: C475302:2-(2-quinolinylazo)-5-dimethylaminobenzoic acid; D001565:Benzoates; D002863:Chromogenic Compounds; D011804:Quinolines; D013662:Tea; D014874:Water Pollutants, Chemical; D062367:ortho-Aminobenzoates; D003035:Cobalt; D014805:Vitamin B 12