BSA法测定超滤膜截留率的不确定度评定

Uncertainty Evaluation for the Determination of the Retention Ratio of the Ultrafiltration Membrane by BSA-67000

截留性能是超滤膜重要的性能指标,截留率和切割分子量又是表征超滤膜截留性能的主要技术参数。基于GB/T 32360—2015《超滤膜测试方法》,依据JJF 1059—2012《测量不确定度评定与表示》,以牛血清白蛋白(BSA-67000)为标准物质,建立截留率测试结果的不确定度评定数学模型,全面分析不确定度来源,评定超滤膜截留率测试结果的不确定度。结果表明:BSA-67000的多分散系数(Mw/(Mn)为1. 101,GPC谱图呈现单峰形式,结构明确、分子量分布窄,完全满足测试需要。对该结果进行了不确定度评定,当包含因子k=2,置信水平为95%时,扩展不确定度为7. 86%,测试结果的不确定度主要来源于测试液取样、重复性测试和BSA-67000的紫外分光光度法测定。

Retention performance is the most important performance indicator of ultrafiltration membrane performance,including two technical parameters which are molecular weight cut off and retention. Based on GB/T 32360—2015 ' Test Methods for Ultrafiltration Membrane',according to the JJF 1059—2012 ' Evaluation and Expression of Uncertainty in Measurement',BSA-67000 was choosed as standard substance,evaluation mathematical model of uncertainty of retention test results was established to analyze the sources of uncertainty,and the retention test results were evaluated. The results indicated that the polydispersity coefficient( Mw/( Mn) of BSA-67000 is 1. 101 and GPC spectrum showed a single peak form,in line with PEG clear structure,molecular weight distribution narrow features,which fully meet the testing needs. The results were evaluated uncertainty. It showed that expanded uncertainty is 7. 86%,when coverage factor is k = 2 and level of confidence is 95%. Uncertainty of the measurement results were mainly from the removing the test sample,repeatability and spectrophotometric determination of BSA-67000.