Abstract:
To further evaluate the precision (repeatability and reproducibility) of the standard measurement method described in YC/T 207-2014, a collaborative study involving 50 laboratories was conducted by China National Tobacco Quality Supervision and Test Center in 2016. The study analyzed three paper samples spiked with solvents at different residual levels. After removing the outliers detected by Cochrane's test and Grubbs' test, the statistical estimations on the repeatability and reproducibility of measurement results for residues of six solvents (methanol, butanone, benzene, 1-ethoxy-2-propanol,
n-butyl acetate and
o-xylene) were carried out according to the methods described in GB/T 6379.2-2004/ISO 5725-2:1994. The results showed that under repeatability conditions, the relative repeatability standard deviations (RSDr) of the above six solvents at three residual levels ranged from 1.7% to 4.5%, which were below the tolerance of 10% required by YC/T 207-2014;under reproducibility conditions, the relative reproducibility standard deviations (RSD
R) of the above six solvents at three residual levels were in the range of 5.6%-14.4% except for those of 1-ethoxy-2-propanol and
o-xylene at the lowest residual level. In addition, good linear relationships were found between the precisions of the method and the mean values of measurement results, therefore the precisions of the measurement results were finally expressed as the linear functions of repeatability standard deviation (
Sr) and reproducibility standard deviation (
SR) corresponding to the mean value of measurement results.