Determination of cadmium by electrothermal atomic absorption spectrometry with flow injection chemical vapor generation from a tetrahydroborate-form anion-exchanger and in-atomizer trapping

摘要

Both electrothermal atomization and flow injection hydride generation parameters were optimized The highest sensitivity and best peak shapes were obtained from Zr-Ir coated graphite tubes with trapping, pyrolysis and atomization temperature of 75 degrees C, 350 degrees C, and 1,200 degrees C, respectively. For an Amberlite IRA-400 column (60 min x 6.6 mm i.d.), the optimum conditions were 3% NaBH4 + 0.5% NaOH, loaded for 25 s at 5.20 mL min(-1), carrier gas flow rate of 125 mL min(-1) and sample acidity 0.30 mol L-1 HNO3, The carrier was deionized water at 5.80 mL min(-1). The limit of detection (3s) in aqueous solution for a 3 mL sample was 2-4 ng L-1, with a sampling frequency of 20 V. Signals were enhanced in the presence of L-cysteine, thiourea and cobalt. The detection limits (3s) were 3-15 ng L-1 for natural water samples and 90-180 ng V for wine, saliva, orange juice, and urine. Percent recoveries were 90 - 104%. The calibration curve was linear up to 300 ng L-1. The characteristic mass (peak area of 0.0044 abs s) was 4.90 pg and the overall transfer efficiency was 38%. Accurate analyses of quality control samples (whale liver and goat blood), and three NIST standard reference materials, freeze-dried urine (SRM 2670), spinach leaves (SRM 1570a), and tomato leaves (SRM 1573a), were made.