EVALUATION OF TWO ACID DIGESTION METHODS IN THE ANALYSIS OF SUGAR CANE LEAF TISSUE (Saccharum officinarum L.)

Abstract

The performance of via dry (DVS) and acid microwave assisted digestion methods (DAAM) was evaluated in the analysis of sugar cane leaf samples. The usual laboratory detection techniques were evaluated [P: visible molecular absorption spectrometry (UV-VIS); K: emission atomic spectrometry (AES); Ca, Mg, Cu, Zn: Flame atomic absorption spectrometry] respect to the Total reflection X ray fluorescence technique (TXRF), for the results obtained by two digestion methods. Digestion methods accuracy and precision was determined through the use of two certified samples: plant tissue n°6 and n°11 (Accreditation and Normalization Commission – Chilean Society of Soil Science) P determination via TXRF reported better results with respect to UV–VIS in sugar cane leaf samples. Digestion methods showed accurate and precise results for Ca when using FAAS or TXRF. For Zn and Cu deviations and variances, associated to the low sample concentration and relation to reagent blank were found. In general, accuracy and precision are related mainly with the concentration range of each element in samples, and with the quantification limit. Regarding analytical performance, no significant differences were found for both digestion methods. Via TXRF detection presents lower analytical efficiency in accuracy and precision, but  better performance with regard to time for analysis.