Determination of Phosphorus, Potassium, and Magnesium in Fertilizers by Inductively Coupled Plasma-Atomic Emission Spectroscopy and Comparison with Other Techniques

Abstract

Phosphorus, potassium, and magnesium in 12 fertilizers were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and results were compared with those obtained by standard gravimetry (phosphorus) and atomic absorption spectrometry (AAS) (potassium and magnesium). ICP-AES and gravimetry were also used to determine water- and citrate-soluble phosphorus in fertilizers. In all cases, precision and accuracy of the ICP-AES method were satisfactory. Certain differences, probably not significant for routine analyses, were observed between ICP-AES and gravimetry in determinations of total and citrate-soluble phosphorus when the measurements were performed strictly under conditions of repeatability.