Determination of Hg and Se in biological materials by chemical vapor generation electrothermal vaporization inductively coupled plasma mass spectrometry using isotope dilution calibration after microwave-assisted digestion with Aqua Regia

Abstract

Propõe-se um método para a determinação de Hg e Se em materiais biológicos por espectrometria de massa com plasma indutivamente acoplado e introdução da amostra por vaporização eletrotérmica após geração química de vapor (CVG-ETV-ICP-MS) e calibração por diluição isotópica. As amostras foram digeridas com água régia em um sistema convencional de microondas. As razões isotópicas usadas para quantificação foram:201 Hg/ 202 Hg e 77 Se/ 82 Se. Borohidreto de sódio foi usado como agente redutor. As temperaturas de retenção e vaporização foram de 150 e 2000 °C, respectivamente. Seis materiais biológicos certificados foram analisados e as concentrações obtidas para Hg e Se foram concordantes com os valores certificados de acordo com o teste-t para um nível de confiança de 95%. Os limites de detecção obtidos foram 0,7 e 3 ng g -1 para Hg e Se, respectivamente. O método é preciso, exato e adequado para a análise de materiais biológicos em rotina e demonstra a viabilidade do uso da diluição isotópica no sistema proposto.A method for the determination of Hg and Se in biological materials by chemical vapor generation electrothermal vaporization inductively coupled plasma mass spectrometry (CVG-ETV-ICP-MS) using isotope dilution calibration after acid digestion is proposed. The samples were digested with aqua regia in a microwave oven. The isotope ratios used for quantification were: Se. A NaBH 4 solution stabilized with NaOH was used as reducing agent. The retention and vaporization temperatures in the graphite tube were 150 and 2000 ºC, respectively. Six certified biological materials were analyzed and the obtained concentrations were in good agreement with the certified values according to the t-test for a confidence level of 95%. The detection limits in the sample were 0.7 and 3 ng g -1 , for Hg and Se respectively. The method is precise, accurate and adequate for the analysis of biological samples in routine and demonstrates the feasibility of using isotope dilution for the proposed system.

Sample preparation methods for determination of Cd, Pb and Sn in meat samples by GFAAS: use of acid digestion associated with a cold finger apparatus versus solubilization methods

“…However, this system requires the use of a small sample mass to prevent the pressure exceeding the safety level. [26][27][28][29][30] Thus, it is essential that the microwave unit presents not only a complete security system to avoid explosions, including control of temperature and pressure, but also an exhaust system. These requirements may make the system more expensive.…”

Determination of zinc and copper in human hair by slurry sampling employing sequential multi-element flame atomic absorption spectrometry

“…Recent reviews highlighted the advantages of direct methods of analysis [2,3]. The slurry sampling is one of the alternatives for direct analysis of solid samples that have been proposed using spectroanalytical techniques as graphite furnace atomic absorption spectrometry (GFAAS) [4], inductively coupled plasma optical emission spectrometry (ICP OES) [5,6] and inductively coupled plasma mass spectrometry (ICP-MS) [7,8]. Methods using FAAS are more limited because of the restrictions of particles size and also sample amounts.…”