Microwave as an alternative to sample preparation in the foliar tissue silicon analysis of wood species for colorimetric determination

Abstract

The aim of this work was to test the viability of microwave digestion for the colorimetric determination of silicon in foliar tissues of wood species. In the test, the correlation coefficient was 0.998 in the concentration range of 0.4 to 7 mg.g-1. Spiked cellulose samples were used and the recovery was high than 90 % in two tested concentrations (2 e 4 mg.g-1). The obtained coefficients of variation were equal to 4.2 % and 7.0 % for espinheira santa (Maytenus ilicifolia) and eucalipto (Eucalyptus benthamii), respectively. The microwave-induced digestion was compared to autoclave-induced digestion by interlaboratorial test, with relative errors smaller than 17 % in all tested samples (n=10). Based on these results, the microwave digestion of foliar tissues samples of wood species showed to be an alternative to determination of silicon by colorimetric method performed at a wavelength of 410 nm.