Guy Maghuin-Rogister

A review of dietary and non-dietary exposure to bisphenol-A.

Due to the large number of applications of bisphenol-A (BPA), the human exposure routes are multiple. We aimed to review shortly the food and non-food sources of BPA, and to evaluate their contribution to the human exposure. Food sources discussed here include epoxy resins, polycarbonate and other applications, such as paperboard and polyvinylchloride materials. Among the non-food sources, exposures through dust, thermal paper, dental materials, and medical devices were summarized. Based on the available data for these exposure sources, it was concluded that the exposure to BPA from non-food sources is generally lower than that from exposure from food by at least one order of magnitude for most studied subgroups. The use of urinary concentrations from biomonitoring studies was evaluated and the back-calculation of BPA intake seems reliable for the overall exposure assessment. In general, the total exposure to BPA is several orders of magnitude lower than the current tolerable daily intake of 50 μg/kg bw/day. Finally, the paper concludes with some critical remarks and recommendations on future human exposure studies to BPA.

LC-MS/MS multi-analyte method for mycotoxin determination in food supplements

A multi-analyte method for the liquid chromatography-tandem mass spectrometric determination of mycotoxins in food supplements is presented. The analytes included A and B trichothecenes (nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, neosolaniol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin and T-2 toxin), aflatoxins (aflatoxin-B1, aflatoxin-B2, aflatoxin-G1 and aflatoxin-G2), Alternaria toxins (alternariol, alternariol methyl ether and altenuene), fumonisins (fumonisin-B1, fumonisin-B2 and fumonisin-B3), ochratoxin A, zearalenone, beauvericin and sterigmatocystin. Optimization of the simultaneous extraction of these toxins and the sample pretreatment procedure, as well as method validation were performed on maca (Lepidium meyenii) food supplements. The results indicated that the solvent mixture ethyl acetate/formic acid (95:5, v/v) was the best compromise for the extraction of the analytes from food supplements. Liquid–liquid partition with n-hexane was applied as partial clean-up step to remove excess of co-extracted non-polar components. Further clean-up was performed on Oasis HLB™ cartridges. Samples were analysed using an Acquity UPLC system coupled to a Micromass Quattro Micro triple quadrupole mass spectrometer equipped with an electrospray interface operated in the positive-ion mode. Limits of detection and quantification were in the range of 0.3–30 ng g−1 and 1–100 ng g−1, respectively. Recovery yields were above 60% for most of the analytes, except for nivalenol, sterigmatocystine and the fumonisins. The method showed good precision and trueness. Analysis of different food supplements such as soy (Glycine max) isoflavones, St Johns wort ( Hypericum perforatum), garlic (Allium sativum), Ginkgo biloba, and black radish (Raphanus niger) demonstrated the general applicability of the method. Due to different matrix effects observed in different food supplement samples, the standard addition approach was applied to perform correct quantitative analysis. In 56 out of 62 samples analysed, none of the 23 mycotoxins investigated was detected. Positive samples contained at least one of the toxins fumonisin-B1, fumonisin-B2, fumonisin-B3 and ochratoxin A.

Quantitative methods for food allergens: a review

The quantitative detection of allergens in the food chain is a strategic health objective as the prevalence of allergy continues to rise. Food allergenicity is caused by proteins either in their native form or in forms resulting from food processing. Progress in mass spectrometry greatly opened up the field of proteomics. These advances are now available for the detection and the quantification of traces of allergenic proteins in complex mixtures, and complete the set of biological tests used until now, such as ELISA or PCR. We review methods classified according to their ability to simultaneously quantify and identify allergenic proteins and underline major advances in the mass-spectrometric methods.

Multiresidue determination of (fluoro)quinolone antibiotics in swine kidney using liquid chromatography–tandem mass spectrometry

New antibiotics were recently developed, among which are the (fluoro)quinolones. This paper presents an analytical method which allows the determination of 11 (fluoro)quinolones in swine kidneys: norfloxacin, ofloxacin, cinoxacin, oxolinic acid, nalidixic acid, flumequine, enrofloxacin, enoxacin, ciprofloxacin, danofloxacin and marbofloxacin. The procedure involves a rapid and efficient pre-treatment by solid-phase extraction (recoveries 83-98%), followed by the sensitive and selective determination of all compounds in a single run using LC-ESI-MS-MS. Multiple reaction monitoring (MRM) was used for selective detection of each (fluoro)quinolone. Quinine was selected as internal standard. The accuracy of the method, expressed as recovery, was between 89 and 109%; the repeatability had a maximum RSD lower than 15%. The limits of detection (LOD) were much lower than the respective Maximum Residue Limits (MRL)/4.

Analysis of EU priority polycyclic aromatic hydrocarbons in food supplements using high performance liquid chromatography coupled to an ultraviolet, diode array or fluorescence detector

High performance liquid chromatography coupled to an ultraviolet, diode array or fluorescence detector (HPLC/UV-FLD) has been used to set up a method to detect the 15(+1) EU priority polycyclic aromatic hydrocarbons (PAHs) in food supplements covering the categories of dried plants and plant extracts excluding oily products. A mini validation was performed and the following parameters have been determined: limit of detection, limit of quantification, precision, recovery and linearity. They were in close agreement with quality criteria described in the Commission Regulation (EC) No 333/2007 concerning the PAH benzo[a]pyrene in foodstuffs, except the not fluorescent cyclopenta[c,d]pyrene for which the UV detection leads to a higher limit of detection. Analysis of twenty commercial food supplements covering mainly the class of dried plants was performed to evaluate their PAHs contamination levels and to test the applicability of the method to various plant matrices. Fifty percent of analyzed samples showed concentration exceeding 2 microgkg(-1) for one or more PAHs.

Gas and liquid chromatography coupled to tandem mass spectrometry for the multiresidue analysis of β-agonists in biological matrices

beta-Agonists are substances used in veterinary and human medicine for the treatment of pulmonary disorders. They have found a use as growth promoters to improve meat-to-fat ratios in cattle but they are not authorized for use in the European Union. Due to their presence in trace levels (usually less than 1 microgram/kg), to the diversity of the illegally used compounds and to the complexity of the biological matrices analysed, the detection of these residues requires a very sensitive and specific method of determination. This work describes the strategy of analysis we developed for five beta-agonists in urine and liver. The combination of improved solid- or liquid-phase extraction methods and LC or GC-MS-MS (in the multiple reaction monitoring mode) has shown to provide a system suitable for the control of these substances. The efficiency of extraction and the sensitivity and selectivity allow this multiresidue detection down to, and below, the UK regulatory level of 0.5 microgram/kg. Moreover, the use of LC removes the need for the derivatisation step (cyclic methylboronate derivatives) which is required prior to GC-MS-MS analysis.

Porcine luteinizing hormone. The amino acid sequence of the β subunit

At the former International Symposium on Protein and Polypeptide Hormones, Ward et al. [l] presented a paper outlining slight modification in the complete primary structure of ovine luteinizing hormone subunit (0-LHP) as compared with their original results [2] . Simultaneously [3], we presented our data concerning the structure of the bovine chain (B-LH/3). A single point of discrepancy was apparent [3,4] in comparing both sequences which was later cleared on re-examination of the ovine structure [5]. In contrast to the complete homology between 0-LHfl and B-LHP, specific differences were expected for the corresponding porcine subunit (P-LH/3) in view of its composition [6]. In this report, the complete primary structure of the reduced and carboxymethylated P-LHP is presented with comparison to our results concerning the bovine chain (B-LH@.

Food flavonoid aryl hydrocarbon receptor-mediated agonistic/antagonistic/synergic activities in human and rat reporter gene assays.

Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor mediating the adverse effects of dioxins and polycyclic aromatic hydrocarbons (PAHs). In this study, we investigated the genetic-, time-, dose-, species- and tissue-dependent AhR-mediated agonistic/antagonistic activities of three food flavonoids: quercetin, chrysin and genistein. To that end, four stably transfected cell lines were used in cell-based luciferase reporter gene assays: three lines were transformed with the ptKLuc vector harbouring four dioxin-responsive elements (DREs) upstream of the thymidine kinase promoter and the luciferase gene (HepG2-Luc, T-47D-Luc and H4IIE-ULg). The fourth is a patented cell line transformed with a different construct: H4IIE DR-CALUX((R)). Both H4IIE cells were compared for their genetic construction. Human hepatoma (HepG2-Luc) and human breast tumour (T-47D-Luc) cells were compared for tissue-dependent effects. Rat hepatoma (H4IIE-ULg) and human hepatoma (HepG2-Luc) cells were compared for species-dependent activities. We concluded that quercetin, chrysin and genistein act in a time-, dose-, species- and tissue-specific way. For example, genistein displayed agonistic activities when exposed to rat hepatoma cells during 6h but not after 24h. Flavonoids displayed agonistic/antagonistic activities in human breast tumour cells, depending on the exposure time, while in human hepatoma cells, only antagonistic activities of flavonoids were measured. In addition, we report, in all the cells, a synergy between an isoflavone and two food contaminants; the 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3-methylcholanthrene, a PAH. In rat cells, this synergy occurred when cells were exposed to flavonoids and contaminant for 6h, while it was observed in human cells only after 24h.

Determination of β-agonists in urine by an enzyme immunoassay based on the use of an anti-salbutamol antiserum

An enzyme immunoassay (EIA) method for β-agonists has been developed using an antiserum raised in rabbits by immunization against 3-O-salbutamol succinate coupled to bovine serum albumin. Horse radish peroxidase coupled to the same salbutamol derivative was selected as tracer. The dose of salbutamol which caused 50% binding inhibition was 16.8 pg per well and the limit of detection of the EIA directly performed on diluted urine was 0.14 ng ml−1 in urine (when the variability of blank values in samples from untreated animals was taken into account). Owing to the large cross reactivities of the antibodies with a number of β-agonists, the present assay is promising for the simultaneous determination of salbutamol, clenbuterol, mabuterol, terbutaline, cimaterol and probably also other β-agonists with a tert-butyl or isopropyl group at the extremity of the aliphatic side chain of the molecule.

Control of the illegal administration of natural steroid hormones in urine and tissues of veal calves and in plasma of bulls

In the context of the control of the illegal administration of natural steroid hormones in cattle husbandry, decision levels of sex steroid hormones were established, taking into account the effect of the treatment, for the cases of the urine of male and female veal calves treated with estradiol and/or testosterone-containing implants, and the plasma of bulls treated by an injection of an estradiol—testosterone cocktail. At each decision level, a score was assigned, that represents the percentage of treated animals detected when the decision limit is applied. Concerning the veal calves, a maximum decision level is proposed for the 17β-estradiol in urine of 1 ng ml−1 in both male and female veal calves, giving a score of 95%. A minimum decision level was set at 2 ng ml−1 for testosterone in urine of male veal calves, with a score of 95% (95% of the implanted male veal calves display a urinary testosterone level lower than 2 ng ml−1). For female veal calves, a maximum decision level was set at 0.45 ng ml−1 for the urinary testosterone concentration (score of 90%). For bulls, the 17β-estradiol concentration in plasma is a good criterion for detecting injected bulls: a maximum decision level was set at 40 pg ml−1, displaying a score ranging from 100 to 45%, 2 and 7 days after the injection, respectively.