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A method for Cr determination in medicinal plants using direct solid sampling graphite furnace high-resolution continuum source atomic absorption spectrometry was developed. Modifiers were dispensable. Pyrolysis and atomization temperatures were 1500 °C and 2400 °C, respectively. Slopes of calibration curves (50–750 pg Cr, R 2 > 0.999) using aqueous and solid standards coincides in 96%, indicated feasibility of aqueous calibration for solid sampling of medicinal plants. Accuracy was checked by analysis of four plant certified reference materials. Results were in agreement at 95% confidence level with certified and non-certified values. Ten samples of medicinal plants were analyzed and Cr contents were in the 1.3–17.7 μg g − 1 Cr range. The highest RSD (n = 5) was 15.4% for the sample Melissa officinalis containing 13.9 ± 2.1 μg g − 1 Cr. The limit of detection was 3.3 ng g − 1 Cr.

Made available in DSpace on 2018-11-26T16:17:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-10-01. Added 1 bitstream(s) on 2021-07-15T15:01:21Z : No. of bitstreams: 1 S0103-50532015001001988.pdf: 156383 bytes, checksum: 4457cf166b3bf7094f730936a7d44849 (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This work describes a procedure for determination of Cd, Ni and V in spices by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) using direct solid sampling (SS). The use of Pd/Mg(NO3)(2) as modifier for Cd, and an additional air-assisted pyrolysis step allowed the use of aqueous calibration for all analytes. Accuracy was checked by analysis of certified reference materials (CRMs) and the results were in agreement to certified values at 95% confidence level (t-test). Eight samples of spices were analyzed by the proposed procedure and by inductively coupled plasma mass spectrometry (ICP-MS). The found concentrations were 88-233 ng g(-1) Cd, 113-2842 ng g(-1) Ni and 154-1007 ng g(-1) V, with precision generally better than 12%. Results obtained by the proposed procedure were in agreement with those obtained by microwave-assisted digestion and ICP-MS determination. The limits of detection were 0.2, 18 and 7 ng g(-1) for Cd, Ni and V, respectively. Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP, Brazil Univ Estadual Paulista, Dept Quim Analit, BR-14801970 Araraquara, SP, Brazil Univ Estadual Paulista, Dept Quim Analit, BR-14801970 Araraquara, SP, Brazil FAPESP: 09/52480-0

Made available in DSpace on 2022-04-30T07:05:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-01 A simple and rugged method to determine Ca, K and Mg in a single aliquot of medicinal plants by high-resolution continuum source flame atomic absorption spectrometry is proposed. Secondary lines for Ca (239.856 nm) and K (404.414 nm), and the alternate line measured at wing of the secondary line for Mg at 202.588 nm allowed calibration within the 20 - 500 mg L-1 Ca and K, and 1.0 - 80 mg L-1 Mg. Twenty samples and three plant certified materials were analyzed. Results were in agreement at a 95% confidence level with reference values. Limits of detection were 2.4 mg L-1 Ca, 1.9 mg L-1 K and 0.3 mg L-1 Mg. The RSD (n=12) were ≤ 5.1% and recoveries were between 83 and 108% for all analytes. Instituto de Química Universidade Estadual Paulista, CP 355 Faculdade de Ciências Exatas e Tecnologia Universidade Federal da Grande Dourados, CP 533 Instituto de Química Universidade Estadual Paulista, CP 355

A procedure is proposed for Pb determination in medicinal plants by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) using direct solid sampling. Among Pd(NO(3))(2), Pd/Mg(NO(3))(2), NH(4)H(2)PO(4) and the W-coated platform tested as chemical modifiers, Pd(NO(3))(2) presented the best performance. Calibration plots (10-1000 pg Pb) with regression coefficients better than 0.999 were typically obtained. Accuracy was checked for Pb determination in five plant certified reference materials. Results were in agreement with reference values at a 95% confidence level (paired t-test). Medicinal plant samples were analyzed by the proposed procedure and line-source GF AAS using slurry sampling as a comparative technique. The RSD was 10% (n=3) for a sample containing 0.88 μg g(-1) Pb. The limit of quantification (dry mass) was 0.024 μg g(-1). The contents of Pb in medicinal plant samples varied in the 0.30-1.94 μg g(-1) range.