The determination of phosphorus and other elements in plant leaves by ICP-MS after low-volume microwave digestion with nitric acid

A procedure for measuring phosphorous in plant leaves is described. Dry-lea f homogenates (<0.1g) were placed in 7 mL Teflon vessels with nitric acid ( 1 mL), microwave digested using the following program: 600 W, 2 min; 0 W, 2 min; 450 W, 45 min, then analyzed by inductively coupled plasma mass spect rometery (ICP-MS). Recoveries were verified by analyzing four plant certifi ed reference materials (CRMs) in parallel with two established procedures f or measuring phosphorus: (a) flow injection analysis (FIA) after catalyzed block digestion with sulphuric acid, and (b) FIA after digestion with sulph uric acid and hydrogen peroxide. The ICP-MS procedure allowed relatively si mple, rapid analysis of phosphorus that was accurate to within +/- 15% of c ertified values, with detection limits (5 mu g/g) and precision (relative s tandard deviation = 4-9%) equivalent to or better than the other procedures . Furthermore the ICP-MS procedure allowed the accurate determination simul taneously with phoshorus.