Testing efficientcy and uncertainty of sample processing using 14C-labelled chlorpyrifos: Part II

Estimation of Efficiency of Processing Soil Samples for Pesticide Residues Analysis

“…As the chopping and mincing in the presence of dry ice improved the efficiency of sample processing in case of plant materials [31] and made possible to grind difficult sample matrices such as straw, stalk etc., we tested the possibility of applying dry-ice to improve the reproducibility and efficiency of processing soil samples. However, the application of dry-ice did not improve the reproducibility of processing wet soils, as the K S values were widely varying and 2 out of 5 tests did not result in well-mixed samples.…”

“…Another approach is to determine the sampling constant, K S , for the process [29] and calculate the uncertainty of sample processing from it for the actual mass of test portions. [30] Systematic studies on the uncertainty of sample processing revealed [28,30,31] that the random error of sample processing of plant materials can be very high and may contribute substantially to the combined uncertainty of the results. Other studies performed with plant matrices [28,[32][33][34] indicated that certain compounds may decompose during sample processing at varying extent which can cause significant systematic error as well as increase the variability of the results.…”

Determination of Triazole Fungicides in Fruits and Vegetables by Liquid Chromatography-Mass Spectrometry (LC/MS)

“…30 g sub-sample was used by Aysal et al, 2007 [7] based on a study by Maestroni et al 2000 [21][22] that showed results produced using the same chopper in the same laboratory gave representative results within generally ≤ 8% relative error of the mean concentration of the original sample.…”

The Use of Radiotracer Techniques for QA/QC Principles in Pesticide Residue Analysis

“…For the same purpose, unlabeled pesticides can also be used, but their applications take much longer and the estimated Figure 1. Use of TLC for the purification of 14 C-trifluralin (Tiryaki 1995) uncertainty of sample processing may be less precise (Maestroni et al 2000).…”

“…Radiotracer technique is also used not only to determine total, extractable, bound and conjugated residues, but also in quality control procedures such as, purity of pesticide active ingredient, uncertainty of sample processing, extraction and clean-up efficiency, and recovery studies (Führ 1987and 1991, Powley 2004, Khan 1995, Maestroni et al 2000.…”