An automated on-line flow system for the pre-concentration and determination of lead by flame atomic absorption spectrometry

• Published in: Microchemical journal 2001, Vol.68 (1), p.41-46
• Main Authors: Ferreira, Sérgio L.C, Lemos, Valfredo A, Santelli, Ricardo E, Ganzarolli, Edgard, Curtius, Adilson J
• Format: Article
• Language: English
• Subjects: 2-(2-benzothiazolylazo)-2- p-cresol; Amberlite XAD-2; Analytical chemistry; Chemistry; Exact sciences and technology; Flame atomic absorption spectrometry; Flow injection system; Lead; Spectrometric and optical methods
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/S0026-265X(00)00166-1

The use of Amberlite XAD-2 modified by 2-(2-benzothiazolylazo)-2- p-cresol (BTAC) as a sorbent in an on-line pre-concentration system for lead determination has been proposed. The procedure is based on the sorption of lead(II) ions onto a minicolumn packed with modified Amberlite XAD-2, followed by elution with 0.10 mol l −1 hydrochloric acid and determination by flame atomic absorption spectrometry. The on-line flow system uses four three-way solenoid valves and is electronically controlled in a time-based mode. Chemical and flow variables were optimized. The results demonstrated that sample solutions containing lead(II) in the concentration range from 3.7 to 300.0 μg l −1 in a solution of pH between 6.5 and 8.5 could be determined, using a pre-concentration time of 2 min. The enrichment factor was 27 for a sample volume of 4.50 ml. The limit of detection was 3.7 μg l −1. The relative standard deviations (R.S.D.) were in the range of 4.4–2.3% for lead concentrations from 50.0 to 300.0 μg l −1, respectively. The method was tolerant to other ions usually present in biological samples. Good accuracy was assured by the analysis of biological reference materials.