Simultaneous Determination of Bioavailable Forms of Copper, Zinc, Iron, Manganese and Sulfur in Reclaimed Soil by Inductively Coupled Plasma Atomic Emission Spectrometry

A portion of the sample (10.00 g) was mixed with 20 mL of diethylenetriamine pentaacetic acid-calcium chloride-triethanolamine (DTPA-CaCl₂-TEA) extractant (the concentrations of DTPA, CaCl₂ and TEA were 0.005, 0.01, 0.1 mol·L^-1 respectively, and the acidity was pH 7.3±0.2), and the mixture was placed into a constant temperature oscillation box to oscillate at 180 r·min^-1 for 2 h with oscillation temperature of (20±2)℃ for extraction of bioavailable forms of copper, zinc, iron, manganese and sulfur. After filtering with filter paper, the filtrate was determined by inductively coupled plasma atomic emission spectrometry. As showed by results, linear relationships between mass concentration of copper, zinc, iron, manganese and sulfur and emission intensity were kept in definite ranges, with detection limits (3.143s) of 0.01, 0.02, 0.02, 0.01, 0.1 mg·kg^-1 respectively. Eight qualified laboratories were invited to conduct precision collaborative test, and the reproducibility limits and reproducibility limits of this method were determined. The proposed method was applied to the analysis of 12 soil reference substances. The determined values of bioavailable forms of copper, zinc, iron and manganese were within the uncertainty ranges of the certified values, and the determined values of bioavailable form of sulfur were basically consistent with those provided by the industry standard methods (for agricultural soil available reference substances) or within the uncertainty ranges of the certified values (for soil available reference substances and loess soil available reference substances).