外加热消解-风冷管回流在测定土壤有机质含量中的应用

Application of External Heating Digestion-Air Cooled Tube Reflow in the Determination of Soil Organic Matter Content

采用电热板加热-风冷管重复回流的重铬酸钾-硫酸消解体系测定土壤中有机质含量,通过研究消解温度、消煮时间、干扰因素对有机质含量的影响。在测定土壤有机质中得出消解温度220℃,消煮时间8 min为最佳消解条件。结果表明:风冷管重复回流可保证消解体系的酸度保持恒定,减少蒸发的同时,有利于土壤有机物的消解。经国家标准物质验证,测定值与标准值吻合,测试结果重现性好,相对标准偏差小于0.88%。该斱法迚一步降低测试成本,且更加环保、可靠、具有环境适应性强、测试效率高等特点,适用于土壤有机质含量的批量快速测定。

The content of organic matter in soil was determined by the potassium dichromate-sulfuric acid digestion system with hot plate heating-air cooled tube repeating reflow.The influence factors of determining organic matter content,including digestion temperature,boiling time and interference factor,were studied.The optimal digestion condition for measurement of soil organic matter was obtained as follows:the digestion temperature 220℃and the boiling time 8 min.The results showed that the repeating reflux of air cooled tube kept the constant acidity of the digestion system and reduced the evaporation,which was beneficial to the dissolution of soil organic matter.The national standard material validation showed that the measured value was in agreement with the standard value,and the test results had good reproducibility.The relative standard deviation was less than 0.88%.This method can further reduce the testing cost,and is more environmentally friendly,reliable,and has strong adaptability to the environment and high testing efficiency.