Flow injection systems with inductively-coupled argon plasma atomic emission spectrometry: Part 1. Fundamental Considerations

Abstract

Flow injection systems with inductively-coupled argon plasma atomic emission spectromeiry are proposed. Effects of flow rates, injected volumes and mixing Coil lengths are investigated and conditions for the measurement of the flow injection transient signal are discussed. The peak profile measured with the spectrometer corresponds well with the estimate of the true sample zone distribution near the inlet of the spectrometer made by a zone-sampling process; thus the plasma is not a limiting factor in the proposed systems. For plant analysis, the system provides nearly zero sample dispersion and so the inherent sensitivity of the spectrometric method is preserved. The results obtained for 10 elements in the NBS Orchard Leaves reference material (SRM 1571) are in good agreement with the certified values. For determinations of calcium and magnesium in dolomitic limestones, cadmium is used as internal standard and so the merging zones configuration is employed. The proposed system provides medium sample dispersion and permits about 100 samples to be analysed per hour. Relative standard deviations of 1.34% and 1.23% were calculated for the calcium and magnesium data, respectively. The analytical results compare favorably with those obtained by normal i.c.p. spectrometry with pneumatic sample aspiration, after manual sample dilution.