ACCREDITATION AND QUALITY ASSURANCE, vol.10, no.10, pp.550-553, 2006 (SCI-Expanded)
Sample processing is a very important component of uncertainty in analytical results. In order to have reliable results, the laboratory sample should be properly processed to obtain statistically homogenous matrix-before the representative test portions are withdrawn for analysis. The use of (14)C-labeled compound is preferable because the analyte can be quantified without cleanup. The method is based on surface treatment of cucumber with (14)C-chlorpyrifos, determination of (14)C-chlorpyrifos activity in the replicate test portions of different size, and determination of the uncertainty of sample processing.