Matrix effects during trace element analysis in plant samples by inductively coupled plasma atomic emission spectrometry with axial view configuration and pneumatic nebulizer

Abstract

Plant sample matrix effects have been investigated during trace element analysis by inductively coupled plasma atomic emission spectrometry with axial view and pneumatic nebulizer. Eight elements often analyzed in environmental samples were studied: As, Cd, Co, Cr, Cu, Ni, Pb and Se. To simulate the effects caused by digested plant samples, the spectral line profiles of analytes were measured on solutions containing various concentrations of elements encountered in plant matrix such as K, Ca and Mg. Depressions in the emission intensities occurred and were more dramatic with high concentrations of the concomitant species. The inter-element effects were found to be caused by the matrix amount entering into the central channel of the plasma. In fact, energy consumed for droplets desolvation and particles of salts vaporization leads to lower plasma temperatures and produce changes in excitation mechanisms. Ion emissions were especially affected. The matrix effects can be removed using a high generator power (1.4 kW) and a moderate uptake flow rate of solution into the plasma (pump speed: 15 rev./min). The use of the natural plant sample led to the same conclusions. These operating conditions decreased the sensitivity but routine analyses of the plant material could be carried out.