Determination of trace metals in waters and compost by on-line precipitation coupled to flame atomic absorption spectrophotometry or ion chromatography

Departamento de Quı́mica Analı́tica. Facultad de Ciencias Quı́micas. Universidad Complutense de Madrid. 28040 Madrid, Spain; Dipartimento di Chimica Analitica. Universita‘ di Torino. Via Pietro Giuria, 5. 10125 Torino, Italy
Talanta (Impact Factor: 3.5). 01/1999; DOI: 10.1016/S0039-9140(98)00303-8

ABSTRACT A general rapid on-line preconcentration method for the determination of trace metals coupled to flame atomic absorption spectrophotometry (FAAS) or ion chromatography (IC) with spectrophotometric detection is described. The method is based on the on-line precipitation of metal hydroxides with sodium hydroxide and their dissolution in a small volume of nitric acid solution. All the chemical and physical variables that affect the efficiency of metal precipitation and elution in the flow injection system have been studied. The detection limits obtained by FAAS are 0.1, 0.3, 0.5 and 0.5 μg l−1 for Zn, Cu, Ni and Pb, respectively. When the on-line precipitation is coupled to IC with post-column derivatization with the spectrophotometric reagent 4-(2-pyridylazo) resorcinol (PAR), the detection limits are 3, 1, 5, 3, and 3 μg l−1 for Cu, Zn, Ni, Co and Mn, respectively. The proposed general method was successfully applied to determine independently the above mentioned metals in compost and tap and river water samples.