Determination of metals in saline and biological matrices by axial inductively coupled plasma atomic emission spectrometry using microconcentric nebulization

Abstract

An axial inductively coupled plasma atomic emission spectrometer equipped with a commercially available microconcentric nebulizer (MCN) was evaluated for the determination of metals in saline and biological samples. The performance of the MCN was optimized regarding the sample uptake rate and nebulizer pressure in terms of signal intensity and signal-to-background ratio. The effect of increasing salt concentrations was also studied. The results were compared with those obtained with a standard concentric glass nebulizer (CGN) for sample volumes, sensitivity and stability. The MCN was shown to reduce the sample consumption from several milliliters to a few hundred microliters for multi-element analyses. The analytical performance with the MCN was generally poorer than with the CGN, but the magnitude of the effects is element dependent. For the 18 elements studied, the detection limits range from 0.05 µg l^–1 (Mn) to 30.48 µg l^–1 (Ca) for the CGN and from 0.13 µg l^–1 (Mn) to 173.66 µg l^–1 (Na) for the MCN. Increasing the salt concentration decreases both the sensitivity and signal stability obtained with both nebulizers, but the effects are more pronounced for the MCN. The method was further evaluated by analyzing three BCR reference materials: CRM 63 Milk Powder, CRM 185 Bovine Liver and CRM 278 Mussel Tissue. Overall, the results obtained with both nebulizers showed good agreement with the certified values.