Determination of manganese and zinc in powdered chocolate samples by slurry sampling using sequential multi-element flame atomic absorption spectrometry |
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Authors: | Erik GP da Silva Ana Carolina do N Santos Antnio CS Costa Dalva M da N Fortunato Ndia M Jos Maria GA Korn Walter NL dos Santos Srgio LC Ferreira |
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Institution: | aUniversidade Federal da Bahia, Instituto de Química, Núcleo de Excelência em Química Analítica da Bahia, Campus Universitário de Ondina, Salvador, Bahia, 40170-290, Brazil;bUniversidade Federal da Bahia, Escola de Nutrição, Campus Universitário do Canela, Salvador, Bahia, Brazil |
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Abstract: | In the present work, a slurry sampling flame atomic absorption spectrometric method to determine directly manganese and zinc in powdered chocolate samples is proposed. The optimization step was performed using univariate methodology involving the following factors: nature and concentration of the acid solution, sonication time, and particle size. The established conditions led to the use of a sample mass of 150 mg, 2.0 mol L− 1 nitric acid solution, sonication time of 15 min, and a slurry volume of 50 mL. This method allows the determination of manganese and zinc with detection limit of 52 and 61 ng g− 1, respectively, and a precision expressed as relative standard deviation (RSD) of 2.6% and 3.2% (both, n = 10) for contents of manganese and zinc of 52.4 and 100.0 μg g− 1, respectively. The proposed method was applied for determination of manganese and zinc in five powdered chocolate samples. In these, the manganese content varied from 42.8 to 52.7 and from 88.6 to 102.4 μg g− 1 of zinc. The analytical results were compared with the results obtained by analysis of these samples after digestion using open vessel and acid bomb digestion procedures and determination using FS-FAAS. The statistical comparison by t-test (95% confidence level) showed no significant difference between these results. |
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Keywords: | Manganese Zinc Slurry FAAS Chocolate |
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