Nitric acid digestion and multi‐element analysis of plant material by inductively coupled plasma spectrometry

Abstract Inductively coupled plasma spectrometry (ICPS) was used for the simultaneous determination of P, K, S, Ca, Mg, Na, Al, Cu, Zn, Mn, Fe, Co, Mo and B in the nitric acid soluble portion of a variety of plant materials. Conditions for pre‐digestion, digestion and the requirement to grind cereal grain were investigated. Digestion with nitric and perchloric acids caused loss of K (due to the low solubility of potassium perchlorate) and B (due to volatilization). The accuracy of Fe and Na determinations using nitric acid digestion was dependent upon the type of plant material. The accuracy and precision of the proposed digestion and analytical procedure was confirmed by co‐operation in an interlaboratory quality assurance program using a variety of standard reference plant materials, and the analysis of National Bureau of Standards, Standard Reference Material 1571 (orchard leaves).