Evaluation of V, IrRu, V-Ir, V-Ru, and W-V as permanent chemical modifiers for the determination of cadmium, lead, and zinc in botanic and biological slurries by electrothermal atomic absorption spectrometry

摘要

Permanent modifiers (V, Ir, Ru, V-Ir, V-Ru, and W-V) thermally coated on to platforms of pyrolytic graphite tubes were employed for the determination of Cd, Ph, and Zn in botanic and biological slurries by electrothemial atomic absorption spectrometry (ETAAS). Conventional Pd + Mg(NO3)(2) modifier mixture was also used for the determination of analytes in slurries and digested samples, Optimum masses and mass ratios of permanent modifiers for Cd, Pb, and Zn in slurry sample solutions were investigated, The 280 mu g of . 280 mu g of V + 200 mu g of Ir, 280 mu g of V + 200 mu g of Ru or 240 mu g of W + 280 mu g of V in 0.2% (v/v) Triton X- 100 Plus 0.5% (v/v) HNOt mixture was found as efficient as 5 mu g of Pd + 3 mu g of Mg(NO3)(2) modifier mixture for obtaining thermal stabilization, and for obtaining best recoveries, Optimization conditions of analytes, such as pyrolysis and atomization temperature, characteristic masses and detection limits, and atomization and background peak profiles were studied with permanent and 5 mu g of Pd + 3 mu g of Mg(NO3)(2) conventional modifiers and compared with each other. The permanent V-Ir, V-Ru, and W-V modifiers remained stable for approximately 250-300 firings when 20 mu l of slurries and digested samples were delivered into the atomizer. In addition, the mixed permanent modifiers increase the tube lifetime by 50-95% when compared with untreated platforms. The characteristic masses and detection limits of analytes (dilution factor of 125 nil g 1) obtained with V-Ir based on integrated absorbance as example for 0.8% (m/v) slurries were 1.0 pg and 3 ng g(-1) for Cd, 18 pg and 17 ng g(-1) for Ph, and 0.7 pg and 4 ng g(-1) for Zn, respectively. The results of analytes obtained by employing V-Ir, V-Ru, and W-V permanent modifier mixture,, in botanic and biological certified and standard reference materials were in agreement with the certified values of reference Materials, (c) 2005 Elsevier B.V. All rights reserved.