Extraction of water-soluble Cl-,NO3-,and SO42-ions in saline alkaline soil and simultaneous determination by ion chromatography
The study was to establish a method for the extraction and determination of water-soluble Cl-,NO3-,and SO42-in saline alkali soil by ion chromatography(IC).Two soil samples from saline alkali soil in Xinjiang and Ningxia were selected.The orthogonal test was conducted to optimize the extraction process of soil water-soluble anions.The ratio of water-extract solution and soil showed a significant impact on the determination results of water-soluble ions.The extraction procedure was set as:the water and soil ratio was 5∶1,the oscillation time was 3 minutes,and the extraction solution was centrifuged prior to passing 0.45 μm filter membrane,the concentrations of water-soluble Cl-,NO3-and SO42-ions in the water-extract solution were simultaneously determined by IC.The results showed that the concentration range of standard working curves for determining the ions by IC was 0.2-20 mg/L.According to the results of measurements of blank data,the detection limits were 0.18 mg/kg for Cl-,0.12 mg/kg for NO3-and 0.38 mg/kg for SO42-,respectively.The relative standard deviation of measured values of each soil sample with 6 replicates was less than 5%.The recovery rate was in ranges of 90.6%-104%when adding the standard ion solution to the soil extracts.The results by IC for determining Cl-,NO3-and SO42-ions in the water-extract of saline alkali soil sampled form 11 different sites had good correlation with the measure values by other method.It was suggested that water-soluble Cl-,NO3-and SO42-ions were extracted from saline alkali soils could be simultaneously determined by IC with high accuracy and precision.
ion chromatographysaline alkali soilwater-soluble Cl-water-soluble NO3-water-soluble SO42-
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