Determination of Cl, P and K in Compound Fertilizer by X-Ray Fluorescence Spectroscopy

About 5.0 g of the 15 calibration samples were taken and to each sample 60 mL of 40 g·L^-1 EDTA solution were added. The mixtures were shaken in a water bath at 80℃ for 1.5 h. After cooling, the solutions were made up to 100.0 mL with water, and filtered to obtain clear solutions for use to prepare the calibration curves. Blank solution and sample solution were prepared in the same way. Polyethylene film with a thickness of 8 μm was selected as the interface material for storage of the sample solution, and the thickness of the test solution layer was 8 mm. Cl, P and K in the test solution were determined by a hand-held energy dispersive X-ray fluorescence spectrometer under optimized instrument conditions. Linear relationships were found between fluorescence intensity and corresponding mass concentration of Cl^-, P₂O₅ and K₂O within definite ranges, and the detection limits (3s) were 0.020, 0.036, 0.032 g·L^-1, respectively. The method was used to determine the content of Cl, P and K in 2 compound fertilizer samples, giving results in consistency with those obtained by national standard method, and the precision of the method higher than that of national standard method.