Investigation of matrix effect on dry inductively coupled plasma conditions using laser ablation sampling

The sample matrix can influence the temperature, electron number density, a nd other excitation characteristics in the inductively coupled plasma (ICP) . These ICP characteristics were investigated by measurements of the ionic to atomic spectral line intensity ratio of a test element (e.g. Mg and Zn). The effect of matrices of calcium (CaCO3 and CaF2), strontium (SrCO3), lit hium (Li2O, Li2CO3 and LiF), magnesium (pure Mg and MgO), and aluminium met al on plasma conditions was studied using laser ablation sampling. Two Nd:Y AG lasers were used to ablate the test element and the matrix simultaneousl y. Different amounts of matrix were ablated by varying one laser irradiance ; the laser irradiance fur the ablation of the test element was kept consta nt. Strontium, calcium, and magnesium had a more pronounced matrix effect t han the easily ionizable elements (Li, Na and K). The matrix effect was ind ependent of the anion. Experimental results suggest that the matrix effects may be due to a mechanism that involves the second ionization level of the elements (Sr, Ca and Mg). Published by Elsevier Science B.V.