RAPID PERCHLORIC-ACID DIGEST METHODS FOR ANALYSIS OF MAJOR ELEMENTS IN PLANT-TISSUE

The nutrient element composition of tissue from a plant species is not fixed. Composition in the plant varies among different plant parts at the same or different physiological stages of maturity, as soil type changes, from day to day, even hour to hour on the same day due to past and current environmental conditions. These observations seem to undermine the general trend in plant tissue analysis to develop quantitative procedures that are time consuming and, therefore, foster insufficient nutrient status monitoring within and/or between different physiological stages of maturity of like or different plant parts. Therefore, until tissue sampling becomes more definitive, a digest procedure with 90-100% recovery should be more than adequate for major elemental analysis. The HClO4 digestion procedures described here meet that requirement and take only 15 to 30 min to complete. N recovery was greater than 100% with the H2O2-HClO4 digestion procedure. However, when HNO3 was combined with H2O2 and HClO4, N was lost, although even then N volatilization occurred only when digestion was extended past clearing.