Determinação catalítica de Selênio em cabelo humano empregando a redução de TAN a DHTAN com íon Brometo como ativador em sistema de AFCM com detecção espectrofotométrica

Abstract

A method spectrophotometric to determination of selenium in human hair was developed using the continuous monosegmented flow analysis with the catalytic effect of Se (IV) in the reduction of the 1,4,6,11-tetraazanaphthacene to l,6-dihydro-l,4,6,l 1-tetraazanaphthacene in presence of the glyoxal and hypophosphorous acid. For this reaction the bromide ion was used as activator of the catalytic action of the Se (IV). The reaction was made the 50 °C and the indicator of the reaction 1,6-dihydro-1,4,6,11-tetraazanaphthacene was monitored by transmittance measures to 600 nm. The calibration curve for Se (IV) described by the equation AAbs = 1,173Cse<iv> + 0,0014 (r2 = 0,9993) is linear to 0.12 pg/mL and the limit of detection is 2.6 ng/mL. The ions Cu (II), Fe (III), Mn (II), Zn (II) e V (V) are interferences in the selenium determination. Acceptable recovery leveis of Se (IV) were obtained by the appropriate use of addition of a pattern of Se (IV). The precision and accuracy of the proposed method were valued using a statistical protocol based on the methodology of addition pattern. The selenium determination in human hair using the proposed method allowed verifying that the same is simple, practical and satisfactory for use in routine.