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It has been evidenced that arsenic in garlic is present in the most toxic inorganic species As(III) and As (V). A non-chromatographic speciation method has been developed for the screening of inorganic toxic species of As in garlic samples by hydride generation atomic fluorescence spectrometry. The determination of As(III) and As(V) was based on the different efficiencies of hydride generation with NaBH 4 with and without a previous reduction with ascorbic acid and KI using a system of two proportional equations corresponding to these two different measurement conditions. The extraction efficiency of total arsenic and the stability of As(III) and As(V) in different extraction media (sulphuric acid, perchloric acid, and methanol/water) were evaluated. Based on the extraction yield and the stability of extracted species, 1.0 mol L −1 H 2 SO 4 was selected as the best extracting solution for speciation analysis. The methodology developed allows us a limit of detection of 0.8 and 0.6 ng g −1 for As(III) and As(V), respectively. The relative standard deviation values were 4% for As(III) and 7% for As(V). This method was applied to determine As(III), As(V), and total As in different Spanish garlic samples. The arsenic (III) content varied from 17.1 to 22.1 ng g −1 and As(V) from 54.7 to 67.6 ng g −1 . The accuracy of the method was confirmed by the analysis of a certified reference material of tomato leaves treated in the same way as the garlic samples.

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Foram estudadas as características de funcionamento de um sistema de nebulização duplo e as condições químicas para a geração de hidretos, assim como as figuras de mérito para os elementos formadores e não formadores de hidretos. Foi caracterizado o desempenho analítico do sistema de nebulização pelos limites de detecção de 0,002 até 0,0026 µg mL-1 para os elementos formadores de hidretos e entre 0,0034 e 0,0121 µg mL-1 para os elementos não formadores de hidretos, o desvio padrão relativo para 10 replicatas ao nível de 0,25 mg mL-1 e percentagens de recuperação entre 97 e 103%. A aplicabilidade do sistema foi demonstrada na determinação simultânea de Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Zn, As, Bi, Sb, Se e Te em amostras certificadas para elementos traços, NIST 1549 (leite em pó desnatado), NIST 1570a (folhas de espinafre), DORM-2 (músculo de cação) e TORT-2 (hepatopâncreas de lagosta). Os resultados obtidos foram concordantes com os teores certificados. The operating characteristics of a dual nebulization system were studied including instrumental and chemical conditions for the hydride generation and analytical figures of merit for both, hydride and non hydride forming elements. Analytical performance of the nebulization system was characterized by detection limits from 0.002 to 0.0026 µg mL-1 for the hydride forming elements and between 0.0034 and 0.0121 µg mL-1 for the non-hydride forming elements, relative standard deviation for 10 replicate measurements at 0.25 mg L-1 level and recovery percentages between 97 and 103%. The feasibiity of the system was demonstrated in the simultaneous determination