Continuous plumbane generation in citric acid‐potassium ferricyanide medium for the determination of lead in environmental samples by atomic absorption spectrometry

Abstract

A continuous plumbane generation‐atomic absorption spectrometric method is described for the determination of trace lead. Citric acid‐potassium ferricyanide was used as the reaction medium for sodium tetrahydroborate(III) reduction. Potassium ferricyanide enhanced the lead signal, while citric acid not only provided the acidity for the plumbane generation but also inhibited the interferences from foreign ions. Under optimized conditions, the sensitivity(0.0044 absorbance unit) and detection limit(3a) were 0.39 μg/L and 0.23 μg/L, respectively. Ten determinations of a 10 μg/L standard lead solution gave a RSD of 1.4%. Interferences from transition metals and hydride forming elements were studied. Copper severely interfered with the reduction. The proposed method has been successfully applied to determine lead contents in water samples and geological standard reference materials.

Key words:

• Lead Determination
• Hydride Generation
• Atomic Absorption Spectrometry
• Potassium Ferricyanide