A potentiometric titration method is established to determine the content of water-soluble chloride ions in soil.Through detailed experiments on extraction temperature,pH value,interference elimination,etc.,the optimal determination conditions are determined:the soil sample is shaken with water at 25℃,and an appropriate amount of nitric acid is added to eliminate the influence of carbonate and sulfate ions,maintaining the pH at 3.0 to 5.0.The detection limit of water-soluble chloride ions in soil by this method is 0.002 g/kg,the precision(RSD,n=7)is 1.7%to 4.8%,and the accuracy(RE)is-0.3%to 1.5%.The method is accurate and reliable,meeting the requirements of the Technical Specifications for Quality Control of the Third National Soil Survey.This method overcomes the drawback of traditional titration methods in which it is difficult to determine the endpoint of samples with severe coloration,and it is generally applicable and easy to promote.
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