title: Spectrophotometric determination with a chromogenic reagent of lead in vegetables.
abstract: A method was developed for the simple, selective, and sensitive spectrophotometric determination of lead in vegetables with synthesized chromogenic reagent 3-[(2,6-dibromo-4-methylphenyl)diazenyl]-4,5-dihydroxy-6-[(2,4,6-tribromophenyl)diazenyl]naphthalene-2,7-disulfonic acid (DBMTBA; 1). In 0.25 M phosphoric acid medium, which greatly increases the selectivity, lead reacts with DBMTBA to form a 1:2 blue complex, which shows maximum absorption at 646 nm. Under optimal conditions, Beer's law is obeyed over the range from 0.09 to 0.8 microg ml(-1) Pb2+, and the apparent molar absorptivity is 1.024x10(5) l mol(-1) cm(-1). The detection limit and the variation coefficient were found to be 2.09 microg ml(-1) and 1.0%, resp. The proposed method has been applied successfully for the determination of lead in vegetables (Solanum melongena fruits, tomato fruits, Ablemoschus esculentus leaves, and Daucous carota leaves) with satisfactory results.
authors.affiliation: Environmental Monitoring Section, Department of Chemistry, Sri Venkateswara University, Tirupati-517 502, Andhra Pradesh, India.
authors.forename: Kailasa Suresh
authors.initials: KS
authors.lastname: Kumar
authors.forename: Lingaladinne
authors.initials: L
authors.lastname: Krishnaiah
authors.forename: Sunnapu Hari
authors.initials: SH
authors.lastname: Babu
authors.forename: Kanchi
authors.initials: K
authors.lastname: Suvardhan
authors.forename: Lokanath B
authors.initials: LB
authors.lastname: Swaroop
authors.forename: Pattium
authors.initials: P
authors.lastname: Chiranjeevi
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D002138:Calibration; D007202:Indicators and Reagents / Q000737:chemistry*; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D009282:Naphthalenesulfonates / Q000737:chemistry*; D012680:Sensitivity and Specificity; D032322:Solanum / Q000737:chemistry*
chemical_list: C517161:3-((2,6-dibromo-4-methylphenyl)diazenyl)-4,5-dihydroxy-6-((2,4,6-tribromophenyl)diazenyl)naphthalene-2,7-disulfonic acid; D001391:Azo Compounds; D007202:Indicators and Reagents; D009282:Naphthalenesulfonates; D007854:Lead