沉积物中黑碳的提取和测定方法:误差分析和回收率实验

Extraction and determination of black carbon in sediments:Error analysis and recovery ratio experiment

介绍了从沉积物中提取黑碳的一种误差较小的改进方法,并对实验误差及引起误差的原因进行了详尽的分析和探讨,同时给出了方法的回收率。经过未均匀处理样品的平行实验,得到实验结果的总体偏差为8.89%,其中个别样品的偏差可达10%～20%;在样品进行了均匀处理后,得到平行实验的总体偏差为3.29%,HCl-HF单步处理的总体偏差为1.96%,而K2Cr2O7氧化处理单步实验的总体偏差为2.50%。其中回收率实验表明,黑碳的回收率可达80%以上。由此可见,所取样品具有代表性,是准确测定沉积物黑碳含量的前提。

An improved and less deviated method for extraction and determination of black carbon in sediments is provided. Meanwhile, the causes contributedto the data deviation are analyzed and probed. The heterogeneity of the sample is the main reason for a gross relative deviation of 8.89%. After the samples being homogenized, the gross relative deviation reduces to 3.29%for the wholeexperimental procedures, of which 1.96%accounts for HCl HF single treatment and 2.50%for K2Cr2O7 oxidation. These deviations seem to coincide with eachother. These can be tested using deviation relay equation. The recovery of our procedure reaches more than 80%. All of these data indicate that this method is feasible for determination of black carbon in sediments. The homogeneity of samples can not be improved by sieving the samples into different grain size. The heterogeneity exists in different grain size portions. Thus, highly representative samples are premise of accurate determination of black carbon content.