Determination of As, Hg and Pb in herbs using slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry.
Analysis of herbs for As, Hg and Pb has been carried out using slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) with flow injection vapor generation. Slurry containing 0.5% m/v herbal powder, 0.1% m/v citric acid and 2% v/v HCl was injected into the VG-ICP-MS system for the determination of As, Hg and Pb that obviate dissolution and mineralization. Standard addition and isotope dilution methods were used for quantifications in selected herbal powders. This method has been validated by the determination of As, Hg and Pb in NIST standard reference materials SRM 1547 Peach Leaves and SRM 1573a Tomato Leaves. The As, Hg and Pb analysis results of the reference materials agreed with the certified values. The precision obtained by the reported procedure was better than 7% for all determinations. The detection limit estimated from standard addition curve was 0.008, 0.003, and 0.007 ng mL(-1) for As, Hg and Pb, respectively.
Atomic spectrometric detectors for flow-injection analysis
Abstract The distinction between liquid chromatography and flow injection analysis is discussed in terms of the underlying concepts, the performance characteristics and the hardware involved. For the last aspect, attention is focused on the role of the detector and the development of spectroscopic detectors for these techniques is discussed. The limitations of atomic spectrometric detectors are discussed for the three most widely used techniques, flame atomic absorption spectrometry, plasma spectrometry and electrothermal atomisation atomic absorption spectrometry, and the recent literature concerned with the use of these techniques for chromatographic detectors is summarized. The use of flow-injection methods to extend the capabilities of the techniques, particularly as far as detection limits and matrix interferences are concerned, is discussed. These topics are illustrated by a detailed review of relevant papers from 1988 and 1989. It is concluded that there is a considerable sustained research effort in this field.
Analysis of samples with high dissolved solids content using flow injection flame atomic absorption spectrometry
Flow injection (FI) sample introduction in flame atomic absorption spectrometry (AAS) was used to analyse samples containing high concentrations of dissolved solids. The Fl system was optimised with respect to carrier flow-rate, nebuliser uptake rate, sample volume and sampling frequency using 30%m/V NaCl solution with 1 mg l–1 Cu. Sensitivity and precision were comparable to those obtained using simple aqueous standards over a broad range of operating parameters. With a 6 ml min–1 carrier flow-rate, 10.5 ml min–1 uptake rate, 330-µl sample volume and 125 h–1 sampling frequency, the precisions (RSD) obtained for 1 mg l–1 of Cu in 30%m/V NaCl and in saturated lithium borate solutions and for 5 mg l–1 Cu in 100%m/V K2HPO4 solution were 2.0, 1.5 and 2.0%, respectively. Repetitive introduction of a saturated lithium borate solution for 465 injections resulted in no deterioration in performance. After 167 consecutive injections of 30%m/V NaCl solution there was a 10% decrease in the peak signal but no degradation in precision. Limiting factors of Fl-AAS and reasons for the tolerance of high dissolved solids in samples are discussed.