摘要
测定土壤阳离子交换量(CEC)的行业标准方法中,以玻璃棒手动搅拌进行离子交换和铵离子的清洗,使用传统方式进行蒸馏,手动滴定测定土壤样品中的阳离子交换量。但是这些方法搅拌操作劳动强度大、蒸馏过程较为繁琐,耗时长、效率低、不利于大批量样品的快速检测。以自制的多位电动搅拌装置代替玻璃棒搅拌,选择乙酸铵加入量、乙酸铵交换次数和交换搅拌时间3个因素,进行3因素3水平正交实验,结合实际操作需要选择加入50 mL乙酸铵溶液、交换1次、搅拌5 min、用乙醇清洗3次,运用全自动凯氏定氮仪进行蒸馏和测定土壤样品中的阳离子交换量。当搅拌时间为5 min、搅拌速度大于100 r/min时,增加搅拌速度对分析结果无影响。对不同酸碱性的国家标准物质和实际样品进行测定,测定结果的相对标准偏差为1.5%~2.4%,且国家标准物质的测定结果均在认定值的不确定范围内,表明方法有较好的精密度和准确度。与标准方法相比,以多位电动搅拌装置代替玻璃棒搅拌,用全自动凯氏定氮仪代替传统的蒸馏方式和手动滴定,自动化程度较高,蒸馏过程操作简单,解放了分析测试人员的双手,降低了劳动强度,自动滴定节约了试剂成本,整个分析效率提高一倍以上,可实现批量化快速检测土壤中的阳离子交换量。
In the industry standard methods for determination of soil cation exchange capacity(CEC),a glass rod is manually stirred for ion exchange and ammonium ion cleaning,and a traditional method is used for distillation,determination of cation exchange capacity in soil samples by manual titration.However,the stirring operation of these methods is labor-intensive,the distillation process is complicated,time-consuming and low efficiency,which is not conducive to the rapid detection of large quantities of samples.In this study,a self-made multi-position electric stirring device was used instead of glass rod to stir,three factors namely the amount of ammonium acetate added,the exchange times of ammonium acetate and the exchange stirring time,were selected to carry out the orthogonal test of 3 factors and 3 levels.According to the actual operation,50 mL ammonium acetate solution was added,exchanged once,stirred for 5 min,and cleaned with ethanol for 3 times.An automatic Kjeldahl nitrogen analyzer was used for distillation and determination of cation exchange capacity in soil samples.When the stirring time was 5 min and the stirring speed was greater than 100 r/min,the increase of stirring speed had no effect on the analysis results.The method was applied to determination of national reference materials and actual samples with different acidity and alkalinity.The relative standard deviation of the results was 1.5%—2.4%,and the determination results of national standard substances were all in the uncertainty range of the certified value,indicating that the method had good precision and accuracy.Compared with the standard method,this method used multiple electric stirring devices instead of glass rod stirring,automatic Kjeldahl nitrogen analyzer instead of traditional distillation method and manual titration,which had a high degree of automation,simple operation of distillation process,liberating the hands of analysis and testing personnel,reducing labor intensity,automatic titration,savsing reagent cost,and increasing analysis efficiency more than doubles.The method can be used for rapid detection of cation exchange quantity in soil in batch.
作者
黄环
唐荣盛
谷娟平
唐碧玉
熊传信
吕长宽
HUANG Huan;TANG Rongsheng;GU Juanping;TANG Biyu;XIONG Chuanxin;LYU Changkuan(China Nonferrous Metal(Guilin)Geology and Mining Co.,Ltd.,Guilin,Guangxi 541004,China)
出处
《中国无机分析化学》
CAS
北大核心
2023年第12期1414-1419,共6页
Chinese Journal of Inorganic Analytical Chemistry
基金
广西科技基地和人才专项项目(桂科AD20325011)。
关键词
多位电动搅拌装置
全自动凯氏定氮仪
土壤阳离子交换量
批量化
快速检测
self-made multi-bit electric stirring device
automatic Kjeldahl nitrogen analyzer
soil cation exchange capacity
batch
rapid test
