Optimization of mineralization procedures for the determination of Mn in soil samples by FAAS

摘要

The aim of this research was to study the influence of sample preparation conditions for total Mn determination in soil by FAAS. The influence of the composition of digestion solutions, initial mass and particle size of the soil sample, and additionof masking substances that eliminate the interference of other elements in the determination of Mn have been studied. On the stage preparation of samples for analysis three mineralization methods of soil were applied: (1) wet method (digestion with concentrated acid: HCl, HF, HClO_4, HNO_3); (2) dry method (digestion with concentrated acids HClO_4 and HNO_3 or HF after initial incineration of the organic matter, fusion with Na_2CO_3 and K_2CO_3); and (3) microwave method (using mineralization setting Nanocolor or digestion with concentrated acids HCl and HNO_3). The Nanocolor system offers two rapid and convenient methods for sample preparation with solid NanOx N and NanOX Metal reagents: a) regular decomposition in a heating block, b) vigorous pressurised decomposition in a microwave oven. The direct FAAS determination of manganese was performed after digestion with the correction solutions of La, Sr, and NH_4Cl. The optimum conditions for total Mn determination in soil by FAAS were established.