Sampling and Sample Processing in Pesticide Residue Analysis

Abstract

Proper sampling and sample processing in pesticide residue analysis of food and soil have always been essential to obtain accurate results, but the subject is becoming a greater concern as approximately 100 mg test portions are being analyzed with automated high-throughput analytical methods by agrochemical industry and contract laboratories. As global food trade and the importance of monitoring increase, the food industry and regulatory laboratories are also considering miniaturized high-throughput methods. In conjunction with a summary of the symposium "Residues in Food and Feed - Going from Macro to Micro: The Future of Sample Processing in Residue Analytical Methods" held at the 13th IUPAC International Congress of Pesticide Chemistry, this is an opportune time to review sampling theory and sample processing for pesticide residue analysis. If collected samples and test portions do not adequately represent the actual lot from which they came and provide meaningful results, then all costs, time, and efforts involved in implementing programs using sophisticated analytical instruments and techniques are wasted and can actually yield misleading results. This paper is designed to briefly review the often-neglected but crucial topic of sample collection and processing and put the issue into perspective for the future of pesticide residue analysis. It also emphasizes that analysts should demonstrate the validity of their sample processing approaches for the analytes/matrices of interest and encourages further studies on sampling and sample mass reduction to produce a test portion.

Analytical approach, dissipation pattern and risk assessment of pesticide residue in green leafy vegetables: A comprehensive review

“…Significant effort has been made to develop and test novel analytical tools and methodologies in pesticide science. If the experimental sample is not sufficiently large to represent the original lot or unit, the total cost, time and efficiency associated with using the advanced analytical instruments and methodologies will not provide useful conclusions, and may result in confusing data (Farha, Rahman, Abd El‐Aty, Jung, et al, ; Lehotay & Cook, ). Therefore, the Ministry of Food and Drug Safety, Republic of Korea () of the Republic of Korea endorsed a sample weight of 20–25 g for extraction to lessen sampling error, to ensure experimental sample homogeneity and to secure low detection limits and quantification with higher precision, thereby enabling MRL compliance.…”

“…The complexity in sample treatment corresponds with the existing matrix interferences and the use of separation techniques, most commonly gas chromatography (Al Mahmud et al, ; D'Antuono et al, ; Farina et al, ; González‐Rodríguez, Rial‐Otero, Cancho‐Grande, & Simal‐Gándara, ; Ikeura, Kobayashi, & Tamaki, ; Park et al, ; Rahman, Sharma, et al, ; Srivastava, Trivedi, Srivastava, Lohani, & Srivastava, ; Tanaka et al, ; Van Dyk, Bouwman, Barnhoorn, & Bornman, ; Walorczyk, ) or liquid chromatography (Farha, Rahman, Abd El‐Aty, Jung, et al, ; Farha, Rahman, Abd El‐Aty, Kim, et al, ; S. W. Kim, Abd El‐Aty, et al, ; S. W. Kim, Rahman, et al, ; Lehotay & Cook, ; Liu et al, ; Pan, Xia, & Liang, ; Park et al, , ; Rahman et al, ; Wołejko et al, ).…”

“…Significant effort has been made to develop and test novel analytical tools and methodologies in pesticide science. If the experimental sample is not sufficiently large to represent the original lot or unit, the total cost, time and efficiency associated with using the advanced analytical instruments and methodologies will not provide useful conclusions, and may result in confusing data Lehotay & Cook, 2015). Therefore, the Ministry of Food and Drug Safety, (2014)…”

“…The Kim, Rahman, et al, 2016;Lehotay & Cook, 2015;Liu et al, 2011;Pan, Xia, & Liang, 2008;Park et al, 2012Park et al, , 2016Rahman et al, 2015;Wołejko et al, 2016).…”

Analysis of mandipropamid residual levels through systematic method optimization against the matrix complexity of sesame leaves using HPLC/UVD

“…Tremendous effort has been put into the development and validation of new analytical tools and methods in pesticide studies. If the tested sample portions do not adequately represent the original lot or unit from which they originated, all of the cost, time and effort involved in using sophisticated analytical instruments and techniques will not produce meaningful results and might provide misleading information (Lehotay and Cook, ). Therefore, the Ministry of Food and Drug Safety (), Republic of Korea recommended a sample weight of 20–25 g for extraction to reduce sampling error, ensure the homogeneity of the tested sample and obtain lower limits of detection and quantification with greater precision for compliance with the maximum residue levels (MRL).…”