TY - JOUR
T1 - Representative sampling of large kernel lots I. Theory of Sampling and variographic analysis
AU - Esbensen, Kim H.
AU - Paoletti, Claudia
AU - Minkkinen, Pentti
N1 - Funding Information:
P.M. expresses his gratitude to the Finnish Cultural Foundation for the grant that has helped him to participate in this research. Aalborg University, campus Esbjerg, provided Guest Professor stipends to P.M. in the period 2008–2009, also gratefully acknowledged. All three authors wish to thank the KeLDA consortium and the Biotechnology and GMO Unit of the Joint Research Centre of the European Commission for making available the original KeLDA data.
PY - 2012/2
Y1 - 2012/2
N2 - Official testing and sampling of large kernel lots for impurities [e.g., genetically-modified organisms (GMOs)] is regulated by normative documents and international standards of economic, trade and societal importance. The focus nearly always includes only analytical issues - omitting, with very few exceptions, proper accounting for sampling errors. With total sampling errors for irregularly distributed contaminants and impurities typically 10-100 times larger than analytical errors, this issue is critical for procedures based on general notions of effective material uniformity. When the focus includes sampling, most guidelines recommend sampling plans based on the assumption that kernel-lot impurities, if present, are randomly distributed. The only exceptions are EC Rec. 787/2004 and prCEN/TS 1568 (2006), which suggest sampling strategies suitable for more heterogeneous situations.A recent field project, KeLDA, documented highly significant heterogeneity in 13 out of 15 randomly chosen soybean kernel shiploads arriving in Europe intended for the feed market. The KeLDA study argued strongly that only sampling guidelines taking this into account can be viewed as authoritative for kernel-lot testing. The Theory of Sampling (TOS) is the only fully comprehensive, scientifically documented approach for representative sampling of all types of heterogeneous lots and materials (trace constituents, contaminants), and, in this context, GMO-contaminated lots constitute no special type.In this three-part series, we re-interpret KeLDA data from a proper TOS perspective. Part I introduces the fundamental principles for process sampling, resolves terminology differences between TOS and ISO usages and defines variographic analysis in the full detail necessary for parts II and III.
AB - Official testing and sampling of large kernel lots for impurities [e.g., genetically-modified organisms (GMOs)] is regulated by normative documents and international standards of economic, trade and societal importance. The focus nearly always includes only analytical issues - omitting, with very few exceptions, proper accounting for sampling errors. With total sampling errors for irregularly distributed contaminants and impurities typically 10-100 times larger than analytical errors, this issue is critical for procedures based on general notions of effective material uniformity. When the focus includes sampling, most guidelines recommend sampling plans based on the assumption that kernel-lot impurities, if present, are randomly distributed. The only exceptions are EC Rec. 787/2004 and prCEN/TS 1568 (2006), which suggest sampling strategies suitable for more heterogeneous situations.A recent field project, KeLDA, documented highly significant heterogeneity in 13 out of 15 randomly chosen soybean kernel shiploads arriving in Europe intended for the feed market. The KeLDA study argued strongly that only sampling guidelines taking this into account can be viewed as authoritative for kernel-lot testing. The Theory of Sampling (TOS) is the only fully comprehensive, scientifically documented approach for representative sampling of all types of heterogeneous lots and materials (trace constituents, contaminants), and, in this context, GMO-contaminated lots constitute no special type.In this three-part series, we re-interpret KeLDA data from a proper TOS perspective. Part I introduces the fundamental principles for process sampling, resolves terminology differences between TOS and ISO usages and defines variographic analysis in the full detail necessary for parts II and III.
KW - Bulk commodity
KW - Contaminant
KW - Fit-for-purpose sampling plan
KW - Genetically-modified organism (GMO)
KW - Kernel sampling
KW - Process sampling
KW - Representative sampling
KW - Theory of Sampling (TOS)
KW - Trace constituent
KW - Variographic analysis
UR - http://www.scopus.com/inward/record.url?scp=84856571309&partnerID=8YFLogxK
U2 - 10.1016/j.trac.2011.09.008
DO - 10.1016/j.trac.2011.09.008
M3 - Article
VL - 32
SP - 154
EP - 164
JO - TrAC - Trends in Analytical Chemistry
JF - TrAC - Trends in Analytical Chemistry
SN - 0165-9936
ER -