A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
Representative sampling of large kernel lots I. Theory of Sampling and variographic analysis
21 December 2011, 02:42:06
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 20 December 2011
Kim H. Esbensen, Claudia Paoletti, Pentti Minkkinen
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 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 heterogeneous situations.A recent field project, KeLDA, documented highly significant heterogeneity in 13 out of 15 randomly chosen soybean kernel shiploads arriving into 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 of articles, 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.
Source: TrAC Trends in Analytical Chemistry, Available online 20 December 2011
Kim H. Esbensen, Claudia Paoletti, Pentti Minkkinen
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 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 heterogeneous situations.A recent field project, KeLDA, documented highly significant heterogeneity in 13 out of 15 randomly chosen soybean kernel shiploads arriving into 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 of articles, 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.
Highlights
► Kernel lot, trace constituents sampling errors outweighs analytical errors by factors 10-100. ► Contemporary kernel lots uniformity assumptions are largely unsubstantiated. ► Theory of Sampling (TOS) introduces fundamental principles for representative sampling. ► Representative process sampling for kernel lots is outlined in full detail (variographics).Nanoecotoxicity effects of engineered silver and gold nanoparticles in aquatic organisms
21 December 2011, 02:42:06
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 19 December 2011
A. Lapresta-Fernández, A. Fernández, J. Blasco
Engineered nanoparticles (ENPs) are increasingly being incorporated into commercial products. A better understanding is required of their environmental impacts in aquatic ecosystems.This review deals with the ecotoxicity effects of silver and gold ENPs (AgNPs and AuNPs) in aquatic organisms, and considers the means by which these ENPs enter aquatic environments, their aggregation status and their toxicity. Since ENPs are transported horizontally and vertically in the water column, we discuss certain factors (e.g., salinity and the presence of natural organic materials), as they cause variations in the degree of aggregation, size range and ENP toxicity. We pay special attention to oxidative stress induced in organisms by ENPs.We describe some of the main analytical methods used to determine reactive oxygen species, antioxidant enzyme activity, DNA damage, protein modifications, lipid peroxidation and relevant metabolic activities. We offer an overview of the mechanisms of action of AgNPs and AuNPs and the ways that relevant environmental factors can affect their speciation, agglomeration or aggregation, and ultimately their bio-availability to aquatic organisms.Finally, we discuss similarities and differences in the adverse effects of ENPs in freshwater and salt-water systems.
Source: TrAC Trends in Analytical Chemistry, Available online 19 December 2011
A. Lapresta-Fernández, A. Fernández, J. Blasco
Engineered nanoparticles (ENPs) are increasingly being incorporated into commercial products. A better understanding is required of their environmental impacts in aquatic ecosystems.This review deals with the ecotoxicity effects of silver and gold ENPs (AgNPs and AuNPs) in aquatic organisms, and considers the means by which these ENPs enter aquatic environments, their aggregation status and their toxicity. Since ENPs are transported horizontally and vertically in the water column, we discuss certain factors (e.g., salinity and the presence of natural organic materials), as they cause variations in the degree of aggregation, size range and ENP toxicity. We pay special attention to oxidative stress induced in organisms by ENPs.We describe some of the main analytical methods used to determine reactive oxygen species, antioxidant enzyme activity, DNA damage, protein modifications, lipid peroxidation and relevant metabolic activities. We offer an overview of the mechanisms of action of AgNPs and AuNPs and the ways that relevant environmental factors can affect their speciation, agglomeration or aggregation, and ultimately their bio-availability to aquatic organisms.Finally, we discuss similarities and differences in the adverse effects of ENPs in freshwater and salt-water systems.
No comments:
Post a Comment