DETERMINATION OF MAGNESIUM IN FERTILIZERS BY INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY - STUDIES OF SOME SPECTRAL AND INTERELEMENT EFFECTS AT DIFFERENT WAVELENGTHS

Four analytical wavelengths of magnesium were tested for determination of Mg from fertilizers by inductively coupled plasma atomic emission spectroscopy (ICP-AES): 202.528, 285.213, and 383.826 nm (Mg I) and 27 9.553 (Mg II). The effects of fertilizer matrix elements on Mg determi nation were examined by adding matrix elements to fertilizer solutions , Multiple linear regression calculations proved a valuable technique for evaluating the effects of matrix elements on Mg determination. The observed interferences at Mg wavelengths may be both spectral and int erelement. Interelement effects were typically caused by Na, K, and Ca , and spectral effects, by P, Fe, and S. The best wavelength for deter mination of Mg in fertilizers by ICP-AES was 383.826 (Mg I).