Spectrophotometric determination with a chromogenic reagent of lead in vegetables.
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.
Kumar
Kailasa Suresh
KS
Environmental Monitoring Section, Department of Chemistry, Sri Venkateswara University, Tirupati-517 502, Andhra Pradesh, India.
Krishnaiah
Lingaladinne
L
Babu
Sunnapu Hari
SH
Suvardhan
Kanchi
K
Swaroop
Lokanath B
LB
Chiranjeevi
Pattium
P
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*
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