We have investigated the composition of the mobile natural organic matter (NOM) present in Callovo-Oxfodian pore water using electrospray ionization mass spectrometry (ESI-MS), atmospheric pressure chemical ionization mass spectrometry (APCI-MS) and emission-excitation matrix (EEM) spectroscopy. The generation of knowledge of the composition, structure and size of mobile NOMis necessary if one wants to understand the interactions of these compounds with heavy metals/ radionuclides, in the context of environmental studies, and particularly how the mobility of these trace elements is affected by mobile NOM. The proposed methodology is very sensitive in unambiguously identifying the in situ composition of dissolved NOM in water even at very low NOM concentration, due to innovative non-disturbing water sampling and ionization (ESI/APCIMS) techniques. It was possible to analyze a quite exhaustive inventory of the small organic compounds of clay pore water without proceeding to any chemical treatment at naturally occurring concentration levels. The structural features observed were mainly acidic compounds and fatty acids as well as aldehydes and amino acids. ©2009 John Wiley & Sons, Ltd.

A method for the specific detection and quantification of recombinant bovine somatotropin (rbST) in bovine blood has been validated according to criteria described in the EU Commission Decision 2002/657/EC. The method is based on a thorough purification procedure followed with the detection by LC-ESI-MS/MS of the tryptic N-terminal peptide specific of the rbST. The recombinant equine somatotropin (reST) is used as internal standard. Performance of the method was assessed based on specificity, linearity, trueness and repeatability. Decision limit (CCa) and detection capability (CCb) were found to be 2.5 ng mL-1 and 6.8 ng mL-1, respectively. This method was subsequently applied to the analysis of serum and plasma collected from two different animals treated with 500 mg of rbST. No significant variations were observed when analyzing either serum or plasma, but an important difference between animals was encountered. In all cases, recombinant bovine somatotropin was still detected two weeks after administration. ©2009 American Chemical Society.

Penicillium expansum is a ubiquitous species for which there are only few reports for chemical investigation in marine environments. Among the numerous secondary metabolites produced by this species, communesins represent a new class of cytotoxic and insecticidal indole alkaloids. In this study, we investigated a marine P. expansum strain exhibiting neuroactivity on a Diptera larvae bioassay. Bio-guided purification led to the isolation and the identification of communesin B as the main active compound by HRMS and 1H and 13C NMR. Liquid chromatography analyses with detection by electrospray ionization coupled with tandem mass spectrometry (LC/ESI-MS/MS) and high-resolution tandem mass spectrometry (LC/HRMS/MS) allowed the identification and characterization of four other known communesins (A, D, E and F) in the crude extract. A fragmentation model for dimethyl epoxide communesins was proposed after detailed interpretation of their MS/MS spectra. Further analyses of the extract using the modelled fragmentations led to the detection of seven new communesins found as minor compounds. Chemical structural elucidation of these new derivatives is discussed based on their fragmentation characteristics. ©2009 John Wiley&Sons, Ltd.

Polychlorodibenzo-p-dioxins, polychorodibenzofurans and “dioxin-like” polychlorinated biphenyls are widespread persistent organic pollutants sharing a similar toxicological pathway mediated by the arylhydrocarbon receptor (AhR). Since the confirmatory method for their measurement at trace levels in complex matrices (using isotopic dilution and gas chromatography–high resolution mass spectrometry) remains time and cost-consuming, growing efforts of the scientific community have been focused on the development of screening approaches, including AhR mediated assays. Unfortunately, AhR ligands are highly diverse and agonistic/antagonistic effects can be observed on procedural blanks and/or sample extracts. In this study, the influence of solvent grade quality on the response of a DNA-binding AhR mediated assay used for screening dioxins has been investigated. Our results demonstrated a very critical impact of this parameter with both strong agonistic and antagonistic effects observed for any tested solvent lot. A small silver nitrate silica column removed partly these interfering compounds and then can be recommended as final purification step. Some preferable grades can be identified and selected in order to guarantee the best possible performances. However, it appears necessary to test every new lot, even if a grade appeared previously compliant. ©2009 Elsevier B.V. All rights reserved.

Current European Union regulation regarding polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in food and feed is based on Toxic Equivalent Quotient (TEQ) concept. For confirmatory purpose, the isotope-dilution method associated to a measurement by gas chromatography coupled with high resolution mass spectrometry is usually the method of choice for precisely measuring the 29 target congeners in three separated fractions. Time and cost related to these analyses are very significant. Various kinds of screening concepts can be considered. In the present study, we elaborated and validated a prediction model for the 2005 World Health Organization TEQ in fish, based on the measurement of 4 PCDD/F and 2 non-ortho dl-PCB congeners, potentially analyzable in a single extracted fraction by gas chromatography coupled with mass spectrometry. Large independent datasets have been used for model elaboration (n = 108) and validation (n = 363, n = 357 and n = 6). ©2009 Elsevier Ltd. All rights reserved.

Among the numerous PCB congeners, most of the dioxin-like PCBs (DL-PCBs) need to be characterized by hyphenated techniques. It has been shown in several instances that these congeners are well related to the total PCB content in fish.We examined datasets collected mainly in France, on freshwater and marine fish and sediments. A statistical model linking DL- and indicator PCBs was developed for a dataset composed of freshwater fishes, and proved to predict well DL-PCBs from indicator PCBs in all other fish sets, including marine ones. Type II error rates remained low in almost all fish sets. A similar correlation was observed in sediments. Non-dioxin-like PCBs elicit various adverse effects and represent 95% of the total PCBs. A European guideline for them is needed; the correlation between DL- and indicator PCBs could help develop this standard in the future. ©2009 Elsevier Ltd. All rights reserved.

Several classes of chemical compounds, exhibiting many different chemical properties, are classified under the generic term of “veterinary drugs”, among which are the antimicrobial medicines such as antibiotics or dyes, and drugs exhibiting growth promoting properties like steroids, b-agonist compounds, thyrostats or growth hormones. For food safety purposes, the resort to these substances in animal breeding has been submitted to strict regulation within the European Union for more than 15 years. Systems of control have therefore been set up within the same period of time to ensure compliance with the regulation. The current strategy relies on targeted analytical approaches focusing on the detection of residues of the administered compounds or their metabolites in different kinds of feed, food or biological matrices. If screening methods, which provide rapid discrimination between compliant and suspect samples, may be based on several techniques such as immunoassays or mass spectrometry, confirmatory methods mainly rely on the latter, which provides adequate specificity and sensitivity for unambiguous identification of the target analytes in biological matrices at trace level. The present article reviews the main mass spectrometric strategies, from the very first, nonetheless still efficient, single MS and multidimensional and high-resolution MS through to advanced isotope ratio MS. Several applications in the field of residue analysis illustrate each of these approaches and focus on the balance between issues related to the compounds of interest (chemistry, matrix, concentration, . . .) and the large offer of mass spectrometric-related technical possibilities, from the choice of the ionization conditions (EI, NCI, PCI, ITD, reagent gases, ESI+, ESI−), to the mass analyzers (single quadrupole, triple quadrupole, ion traps, time-of-flight, magnetic sectors, isotope ratio mass spectrometer) and corresponding acquisition modes (full scan, LR–SIM, HR–SIM, SRM, precursor scan, . . .). All the displayed strategies, from the importance of sample preparation to MS analysis to potential derivatization steps and chromatographic separation parameters are discussed in that context. Besides the advantages of each strategy, main issues associated to such MS approaches are commented with an emphasis not only on such critical points as ion suppression and resolution, but also on the adequacy of the current regulation regarding the evolution of the technology. Finally, future trends which may lead to strong and positive impacts in the field of residue analysis are presented, including latest developments and improvements in chromatography or software dedicated to signal acquisition and data analysis. © 2009 Elsevier B.V. All rights reserved.

NDL-PCBs dietary intake was recently estimated in France by combining results of food products contamination by NDL-PCBs (1665 samples collected through 2002–2006 national monitoring programs) with food consumption data of the French “INCA” survey (individual and national survey of dietary intake, performed in 1998–1999). The mean dietary intake of NDL-PCBs estimated from the sum of 6 congeners (PCB 28, 52, 101, 138, 153, 180) is 7.6, 7.7 and 12.9 ng/kg bw/d for women of childbearing age (19–44 years), adults (15 years and over) and children (3–14 years), respectively. Impact of draft maximal levels (MLs) for NDL-PCBs in some foodstuffs was evaluated. The exposure scenario indicates that use of European draft MLs would have a very limited impact on the French population dietary exposure compared with the existing situation (no MLs). Simulations show that lowered MLs required for reducing significantly the French exposure would result to reject more than 20% of the targeted products from the French market compared with 1.3% according to the European draft MLs. © 2009 Elsevier Inc. All rights reserved.