Extraction of Analytes with a Composite Solution-Simultaneous ICP-AES Determination of Quick-Acting K and Effective P, Fe, Mn, Cu, Zn in Alkaline Soil

5.000 0 g of alkaline soil sample (which had been dried in air and filtered through a sieve with bore size of 2 mm priliminarily) was extracted under vibration with 50 mL of a composite solution of ammonium hydrogen carbonate, diethylene triamine penta acetic acid (DTPA) and calcium chloride (amounts of the 3 compounds in 1 liter of the solution were 79.0, 1.967, 1.47 g respectively, and the acidity of the composite was adjusted to pH 7.65±0.05) at 25℃ for 90 min. The mixture was filtered on a dry phosphorus-free filter paper and the filtrate was diluted 5 times with water. The diluted solution was used for ICP-AES analysis, during which CID detector and HF-resistant atomizer were adopted. Linear relationships between values of the response signals and mass concentrations in definite ranges were obtained for the 6 elements determined. Values of detection limits (3s) for the 6 elements were found in the range of 0.033 to 0.096 mg·kg^-1. A CRM of GBW 07459 was analyzed by the proposed method, results of the 6 elements obtained were in consistency with their certified values, and values of RSDs (n=11) found were all less than 4.0%. In addition, only 2.5 h were necessary for determination of the 6 elements in a single sample.