Spectrophotometric determination of lead in biological samples with dibromo-p-methyl-methylsulfonazo

• Published in: Talanta (Oxford) Vol. 48; no. 3; pp. 511 - 516
• Main Authors: Li, Zaijun, Zhu, Zhenzhong, Chen, Yepu, Hsu, Chung-Gin, Jiaomai Pan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.1999; Oxford Elsevier
• Subjects: Analytical chemistry; Biological samples; Chemistry; Dibromo-p-methyl-methylsulfonazo; Exact sciences and technology; Lead determination; Spectrometric and optical methods; Spectrophotometry; Dibromo-p-methyl-methylsulfonazo; Spectrophotometry; Biological samples; Lead determination; Biological compound; Absorption spectrometry; Sensitivity; Chromogenic reagent; Bisazo dye; Interelement effect; Detection limit; Lead; Standard deviation; Lead Complexes; Selectivity
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/S0039-9140(98)00247-1

A new highly sensitive and selective chromogenic reagent, dibromo-p-methyl-methylsulfonazo (DBM-MSA), was studied for determination of lead. In 0.24 mol l−1 phosphoric acid medium, which greatly increases the selectivity, lead reacts with DBM-MSA to form a 1:2 blue complex which has a sensitive absorption peak at 642 nm. Under the optimal conditions, Beer's law was obeyed over the range 0–0.6 μg ml−1 Pb(II). The molar absorptivity and Sandell's sensitivity are 1.02×105 l mol−1 cm−1 and 0.00203 μg cm−2, respectively. The limit of quantification, limit of detection and relative standard deviations were found to be 7.30 and 2.21 ng ml−1 and 1.1%, respectively. It is found that, except for Ca(II) and Ba(II), all foreign ions studied do not interfere with the determination. The interference caused by Ca(II) and Ba(II) can be easily eliminated by prior extraction with potassium iodide-methylisobutylketone. The method has been applied to the determination of lead in some biological samples with satisfactory results.