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Mol, H.G.J. (author), Rooseboom, A. (author), van Dam, R. (author), Roding, M. (author), Arondeus, K. (author), Sunarto, S. (author), TNO Kwaliteit van Leven (author)The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phase extraction (using primary-secondary amine and graphitized carbon black) and large-volume (20 μL) injection. The same extract, before clean-up and after...article 2007
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Kerkdijk, H. (author), Mol, H.G.J. (author), van der Nagel, B. (author), TNO Kwaliteit van Leven (author)A new concept for cleanup, based on volume overloading of the cleanup column, has been developed for on-line coupling of gel permeation chromatography (GPC), solid-phase extraction (SPE), or both, to gas chromatography (GC). The principle is outlined and the applicability demonstrated by the determination of pesticide residues in food matrixes...article 2007
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van Mispelaar, V.G. (author), Janssen, H.G. (author), Tas, A.C. (author), Schoenmakers, P.J. (author), TNO Kwaliteit van Leven (author)For practical chromatographers it is extremely difficult to judge the merits and limitations of new technological developments. On the other hand, it is nearly impossible for those at the forefront of technology to judge the implications of their efforts for all specific applications of chromatography. Both chromatographers and researchers can...article 2005
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van Mispelaar, V.G. (author), Smilde, A.K. (author), de Noord, O.E. (author), Blomberg, J. (author), Schoenmakers, P.J. (author), TNO Kwaliteit van Leven (author)Comprehensive two-dimensional gas chromatography (GC × GC) has proven to be an extremely powerful separation technique for the analysis of complex volatile mixtures. This separation power can be used to discriminate between highly similar samples. In this article we will describe the use of GC × GC for the discrimination of crude oils from...article 2005
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van Mispelaar, V.G. (author), Tas, A.C. (author), Smilde, A.K. (author), Schoenmakers, P.J. (author), van Asten, A.C. (author)Quantitative analysis using comprehensive two-dimensional (2D) gas chromatography (GC) is still rarely reported. This is largely due to a lack of suitable software. The objective of the present study is to generate quantitative results from a large GC x GC data set, consisting of 32 chromatograms. In this data set, six target components need to...article 2003
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van der Schans, M.J. (author), Lander, B.J. (author), van der Wiel, H. (author), Langenberg, J.P. (author), Benschop, H.P. (author), Prins Maurits Laboratorium TNO (author)In continuation of our investigations on the toxicokinetics of the volatile nerve agents C(±)P(±)-soman and (±)-sarin, we now report on the toxicokinetics of the rather nonvolatile agent (±)-VX. A validated method was developed to determine blood levels of (±)-VX by means of achiral gas chromatography at blood levels ≥10 pg/ml. The ratio of the...article 2003
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TNO BIBRA (author), Scotter, M.J. (author), Castle, L. (author), Massey, R.C. (author), Brantom, P.G. (author), Cunninghame, M.E. (author)Five food-grade mineral hydrocarbon (MHC) materials; a low melting point wax (LMPW), a synthetic wax (C80W) and three white oils (N15H, N70H and P70H) were administered orally to female Fischer-344 rats for 28 and 90 days at a dose level of 2% in the diet. Tissues were examined at autopsy for any treatment-related histopathological changes. The...article 2003
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Cappaert, N.L.M. (author), Klis, S.F.L. (author), Muijser, H. (author), Kulig, B.M. (author), Ravensberg, L.C. (author), Smoorenburg, G.F. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The present study was designed to compare the ototoxic effects of volatile ethyl benzene in guinea pigs and rats. Rats showed deteriorated auditory thresholds in the mid-frequency range, based on electrocochleography, after 550-ppm ethyl benzene (8 h/day, 5 days). Outer hair cell (OHC) loss was found in the corresponding cochlear regions. In...article 2002
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Hooijschuur, E.W.J. (author), Kientz, C.E. (author), Brinkman, U.A.T. (author)Today, the determination of chemical warfare agents (CWAs) is an important area of application in analytical chemistry. Chromatographic, capillary electrophoretic and mass spectrometric techniques are primarily used for the identification and quantification of a broad field of classical CWAs in environmental samples and neutralization masses,...article 2002
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Dallinga, J.W. (author), Krul, C.A.M. (author), Tenfelde, A. (author), Moonen, E.J.C. (author), Vermeer, I.T.M. (author), van Doorn, D. (author), Schothorst, R.C. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The thermal energy analyser (TEA) is considered to be the gold standard for the determination of nitrosamines. However, since many laboratories cannot justify the use of such a very specific detection system, alternative detection methods are useful. While standard gas chromatography (GC) detectors lack the selectivity of the TEA detector, mass...article 2001
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Ingelse, B.A. (author), van Dam, R.C.J. (author), Vreeken, R.J. (author), Mol, H.G.J. (author), Steijger, O.M. (author), TNO Voeding Centraal Instituut voor Voedingsonderzoek TNO (author)It was demonstrated that four out of six of the very polar organophosphorus pesticides (OPs), i.e. acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl and vamidothion, could not be extracted from water using commonly available SPE cartridges. In addition, GC analysis on all six compounds was found to be troublesome due to their...article 2001
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Hissink, A.M. (author), Wormhoudt, L.W. (author), Sherratt, P.J. (author), Hayes, J.D. (author), Commandeur, J.N.M. (author), Vermeulen, N.P.E. (author), van Bladeren, P.J. (author), Centraal Instituut voor Voedingsonderzoek TNO TNO Voeding (author)A physiologically-based pharmacokinetic (PB-PK) model was developed for ethylene dibromide (1,2-dibromoethane, EDB) for rats and humans, partly based on previously published in vitro data (Ploemen et al., 1997). In the present study, this PB-PK model has been validated for the rat. In addition, new data were used for the human class ΘGST T1-1....article 2000
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Simal-Gándara, J. (author), Sarria-Vidal, M. (author), Rijk, M.A.H. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)A liquid chromatographic method with evaporative mass detection (EMD) is described for the determination of paraffins in food contact materials that do not contain polyolefin oligomers, or paraffins migrating from these materials into fatty food simulants or certain simple foods. A normal-phase column operating at maximum column efficiency...article 2000
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Srikumar, T.S. (author), Wezendonk, B. (author), van Dokkum, W. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)In the present pilot study, for investigating the physiological effects of different types of nondigestible oligosaccharides, we have validated the application of methodologies for the analysis of bile acids and neutral steroids in feces of human subjects. The accuracy of the extraction and chromatographic procedures for the analyses of bile...article 1998
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Degenhardt, C.E.A.M. (author), Kientz, C.E. (author), TNO Prins Maurits Laboratorium (author)The use of large volume injections has been studied for the verification of intact organophosphorus chemical warfare agents in water samples. As the use of ethyl acetate caused severe detection problems new potential solvents were evaluated. With the developed procedure, the nerve agents sarin, tabun, soman, DFP and VX can be determined in...article 1996
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Hissink, A.M. (author), van Ommen, B. (author), van Bladeren, P.J. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)Toxicity of halobenzenes has been ascribed mainly to their epoxides, but recent studies with bromobenzene have shown that secondary quinone metabolites are also involved in the alkylation of hepatic proteins. However, the relative contribution of the quinones and the epoxides to the toxicity of halobenzenes is still unclear. In order to...article 1996
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Bogaards, J.J.P. (author), van Ommen, B. (author), Wolf, C.R. (author), van Bladeren, P.J. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)1,2-Dichlorobenzene 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2,3,5-tetrachlorobenzene, and pentachlorobenzene were incubated with microsomes derived from cell lines expressing human CYP1A1, CYP1A2, CYP3A4, CYP2E1, or CYP2D6. The formation of phenolic metabolites as determined by gas chromatographic analysis evealed that CYP2E1 possessed...article 1995
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Feron, V.J. (author), Jetten, J. (author), de Kruijf, N. (author), van den Berg, F. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)As part of a multi-client project, the potential public health risks of the reuse of polyethylene terephthalate (PET) refillable bottles (PRBs) following possible misuse has been investigated. Participants in the project provided data and information from previous studies conducted independently at contract laboratories. These studies were...article 1994
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Gaubius Instituut TNO (author), Kwekkeboom, J. (author), Princen, H.M.G. (author), van Voorthuizen, E.M. (author), Kempen, H.J.M. (author)Activity of cholesterol 7α-hydroxylase (EC 1.14.13.17) in freshly isolated hepatocytes from unweaned piglets (2 to 3 weeks old) was 16-times lower as compared to hepatocytes from weaned piglets (7 to 8 weeks old). The monolayer culture activity remained low in unweaned piglet hepatocytes. In contrast, in cultured hepatocytes from weaned piglets,...article 1990
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Mulders, Ed.J. (author), van Impelen-Peek, H.A.M. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)Samples of barley, wheat and maize were analysed for deoxynivalenol (DON). Samples were extracted with aqueous chloroform-ethanol. The extract was purified by column chromatography on silica gel. DON was derivatised with heptafluorobutyric (HFB) acid anhydride. The glassware was silylated to prevent deterioration of the HFB derivative, which...article 1986
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