SIMULTANEOUS DETERMINATION BY INDUCTIVELY -COUPLED PLASMA SPECTROMETRY N, P, K, CA, CU, MG, FE, MN AND ZN IN PLANT-SAMPLES

The use of inductively coupled plasma spectrometry was investigated fo r the simultaneous determination of nitrogen and eight other elements in plant samples. A modified version of the Kjeldahl method was used f or the digestion of plant material (wet ashing of 250 mg of sample by 5 ml of H2SO4, 5 ml of H2O2 and no catalyst). The validity of the proc edure has been accomplished on different standard reference materials. Reproducibility and accuracy were satisfactory for P, K, Ca, mg, Mn a nd Zn. For these elements, the method allows for a routine determinati on. However, the ICP sensitivity was too low for a good measurement of nitrogen and copper. Their concentrations can be easily determined by the colorimetric method (N) or ETAAS (Cu) on the same digest. For iro n, the results were not reliable and linked to the possible of Fe in s olution. Performances and limitations of the method are also reported.