土壤中胡敏酸提取方法的优化

Optimization of Humic Acid Extraction in Soils

以国际腐殖质协会(IHSS)推荐的胡敏酸提取方法为基础,以去有机质土壤中添加胡敏酸所配制的土壤为研究对象,引入超声作为胡敏酸提取的辅助条件,采用批次试验优化了土壤中胡敏酸的提取方法。结果表明,基于胡敏酸提取回收率和精密度,在室温下获得的优化提取方法为:液土比为8:1、提取次数为3次、Na OH溶液浓度为0.05 mol/L、超声功率为120 W、超声时间为30 min;在此优化条件下,胡敏酸的回收率为94.73%±1.50%,显著大于IHSS推荐方法的回收率64.76%±0.28%,变异系数CV为1.59%、小于10%。相对于IHSS提取法,此优化提取法具有胡敏酸提取回收率高、资源节约、胡敏酸变性小、提取时间短等优点。

On the basis of humic acid extraction method recommended by the International Humic Substances Society （IHSS）, the soil prepared by mixture of organic soil and humic acid is taken as the study target and ultrasound is used as the auxiliary condition for humic acid extraction. Humic acid extraction method is optimized through batch experiments in the paper. The results show that on the basis of recovery rate and precision of humic acid extraction, the optimized extraction method at room temperature is as follows： liquid-to-soil ratio is 8：1; extraction is for 3 times; concentration of NaOH solution is 0.05mol/L; ultrasonic power is 120W; and ultrasonic time for extraction is 30 minutes. Under such optimized conditions, the recovery rate of humic acid from soils is 94.73% ± 1.50%, significantly more than that of the method recommended by IHSS （64.76% ± 0.28%）. The coefficient of variation （CV） is 1.59%, less than 10%. Compared with the method recommended by IHSS, the optimized extraction method is much more advantageous with such features as high extraction recovery rate of humic acid, resource saving, less denaturation of humic acid and shorter extraction time.