Collaborative Study of Wet and Dry Ashing Techniques for the Elemental Analysis of Plant Tissue by Atomic Absorption Spectrophotometry

Seven laboratories participated in a collaborative study of wet ashing of plant material with a nitric-perchloric acid mixture and dry ashing at 500°C in order to determine the elements calcium, copper, iron, magnesium, manganese, potassium, and zinc by atomic absorption spectrophotometry. Five different homogeneous leaf tissue samples were analyzed and a synthetic standard solution containing all of the elements studied was included to evaluate sample preparation errors independent of instrument errors. The results indicated that plant tissue preparation by either wet or dry ashing gave similar elemental composition results for the tissues analyzed. The wet and dry ashing techniques have been adopted as official first action.