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Validate a method for the determination of Cadmium and Lead by using Stripping Chronopotentiometry (SCP) obtained by thin mercury film deposited on rotating disk electrode (TMF-RDE)
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Abstract(s)
Neste trabalho, um novo método foi desenvolvido e validado para a determinação de Cd e Pb em água da torneira, com base num eléctrodo de disco rotativo (RDE-TMF), utilizando cronopotenciometria de redissolução (SCP). A espessura do TMFE foi determinada foi (1,46 ± 0,06) x 10-3 C para um intervalo de confiança de 95%. O procedimento foi composto por: potencial de deposição - 0,78 V; tempo de deposição 90 s; corrente de redissolução 5 μA e agitação de 1500 rpm. Para ambos os metais, a linearidade obtida dentro do intervalo de concentração de (2,5 × 10-9 a 1 × 10-7 M) percentagens de recuperação de foram 111 ± 15% e 103 ± 11% foram obtidos para o cádmio e para o chumbo, respectivamente (com base nos resultados dos materiais de referência certificados). Os limites de detecção obtidos para o Cd e Pb foram de (4,7 ± 3,8) x 10-10 M e (3,2 ± 0,4) x 10-10 M, respectivamente, e foram também obtidos valores de CV < 8%. O método analítico SCP revelou-se eficaz para a determinação de cádmio e chumbo na água da torneira utilizando o filme fino de mercúrio depositado sob um eléctrodo de disco rotativo.
A new validated method for Cd and Pb determinations in tap water, based on rotating disk electrode (TMF-RDE), using stripping chronopotentiometry (SCP), was developed. The TMFE thickness determined was determined at (1.46 ± 0.06) × 10-3 C for 95% confidence interval. The procedure comprised: deposition potential - 0.78 V; deposition time 90 s; stripping current 5 μA and stirring rate 1500 rpm. For both metals linearity was achieved within the concentration range of (2.5 × 10-9 to 1 × 10-7 M) with a high value of the regression coefficient based on the results of the Certified Reference Materials the trueness values in terms of % recovery were found to be 111 ± 15 % and 103 ± 11 % for cadmium and lead respectively. Detection limits of (4.7 ± 3.8) × 10-10 M and (3.2 ± 0.4) × 10-10 M were obtained for Cd and Pb, respectively, and CV values < 8% were observed. SCP was found to be an effective method for cadmium and lead in tap water by using thin mercury film on rotating disk electrode.
A new validated method for Cd and Pb determinations in tap water, based on rotating disk electrode (TMF-RDE), using stripping chronopotentiometry (SCP), was developed. The TMFE thickness determined was determined at (1.46 ± 0.06) × 10-3 C for 95% confidence interval. The procedure comprised: deposition potential - 0.78 V; deposition time 90 s; stripping current 5 μA and stirring rate 1500 rpm. For both metals linearity was achieved within the concentration range of (2.5 × 10-9 to 1 × 10-7 M) with a high value of the regression coefficient based on the results of the Certified Reference Materials the trueness values in terms of % recovery were found to be 111 ± 15 % and 103 ± 11 % for cadmium and lead respectively. Detection limits of (4.7 ± 3.8) × 10-10 M and (3.2 ± 0.4) × 10-10 M were obtained for Cd and Pb, respectively, and CV values < 8% were observed. SCP was found to be an effective method for cadmium and lead in tap water by using thin mercury film on rotating disk electrode.
Description
Dissertação de Mestrado, Qualidade em Análises, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2012
Keywords
Análises laboratoriais Controlo da qualidade Água potável Cádmio Chumbo