Development of Analytical Reference Material for Proficiency Test of Pesticide Multi-residue Analysis in Green-pepper

Abstract

This study was to develop the analytical reference material of green-pepper for multi-residue analysis of pesticides. According to the ISO Guide 35, ISO Guide 13528 and EURL-PT protocol, the homogeneity, stability, assigned value and uncertainty were calculated to assess if it was suitable to be used as the proficiency test or quality control. The values of the within-bottle standard variation (s wb ) and the between-bottle standard variation (s bb ) were 1.7~3.7% of assigned value according to the requirement of the ISO guide 35. And, the uncertainty (u* bb ) due to inhomogeneity was 0.8~1.1% for all pesticides. The storage stabilities of ten-pesticides at various conditions were assessed. For all target pesticides, the slop (b 1 ) values were smaller than the corresponding values of [t 0.95,n-2 ×s(b 1 )] specified by the ISO guide 35, indicating that there were no statistically significant decreases in the concentration of the target pesticides when the analytical reference material was stored at room temperature (20~30 o C) for 7 days, freezing (-20 o C) for 30 days and deep freezer (-80 o C. except for bifenthrin, fenpropathrin) for 245 days. For proficiency test by using it developed by Korea Institute of Toxicology, inter-lab test was performed with eight organization performing the residual pesticide analysis. We found that there were some different results among them. Some were assessed as questionable or unacceptable for two pesticides and one organization didn't analyze the six pesticides. From these results, this green-pepper analytical reference material containing ten-pesticides could be used as a tool for the proficiency test to improve the reliability or consistency for pesticide residue's results.