|
 LINEX Publications
Pestizidanalytik in trauben mit LV-DTD/DMI-GC/TOF-MS.
LaborPraxis Dec. 2002.
Analyses of the wood preservative component N-cyclohexyl- diazeniumdioxide in impregnated pine sapwood by direct thermal desorption-gas chromatography-mass spectrometry.
Jüngel, P.; De Koning, S.; Brinkman, U. A. T.; Melcher, E.: Journal of Chromatography A, Amsterdam 953 (2002) S. 199-205.
<< Read Abstract >>
Investigations concerning the qualitative and quantitative determination of the organic wood preservative component N-cyclohexyl-diazeniumdioxide (HDO) in treated timber were carried out by means of direct thermal desorption–gas chromatography–mass spectrometry (DTD–GC–MS). It could be shown that the identification of HDO in treated pine sapwood (Pinus sylvestris L.) is relatively simple using this analytical technique. Quantification of this active ingredient can be carried out using the peak area of the specific mass fragment m/z 114. A calibration curve with a high correlation coefficient was obtained in the range from 40 to 550 mg HDO per kg timber. Furthermore it can be deduced that the results obtained are characterised by an excellent reproducibility with standard deviations ranging from 5 to 10% in general. For the chosen experimental set up a detection limit of 4 mg HDO per kg treated pine sapwood was calculated, although merely 20% of the active ingredient was desorbed.
Automated liner exchange - A novel approach in direct thermal desorption-gas chromatography.
De Koning, J.A.; Blokker, P.; Jüngel, P.; Alkema, G.; Brinkman U. A.T.: Chromatographia, Wiesbaden 56 (2002) S. 185-190.
<< Read Abstract >>
A system was developed for fully automated liner exchange in direct thermal desorption— gas chromatography— mass spectrometry (DTD-GC-MS). Samples are put into a newly developed liner which is capped with a standard crimp cap. The liners are placed in a sample tray and transported to the thermal desorption device. Both liner transport and liner exchange (which can be performed after each analysis) are automated. The system was tested for spores and pollen, vegetable oil, wood (preservative), car exhaust (BTEX), and tobacco (nicotine) analysis to demonstrate the robustness and flexibility of the approach.
Trace-level determination of pesticides in food using difficult matrix introduction–gas chromatography–time-of-flight
mass spectrometry
Sjaak de Koning, Gunter Lach, Manfred Linkerhagner, Ralf Loscher, Peter Horst Tablack, Udo A. Th. Brinkman.
Journal of Chromatography A, 1008 (2003) 247–252
<< Read Abstract >>
A procedure for the fully automated analysis of food samples by means of difficult matrix introduction–gas chromatography–time-of-flight mass spectrometry (DMI–GC–ToF MS) is discussed. After extraction, samples require very little clean-up and are injected in a micro- or µ-vial which is held in a liner. Next, the liner is placed in the injector and the contents of the vial are thermally desorbed and led directly to the capillary GC column. After GC–ToF MS analysis, the data are processed automatically using a peak deconvolution algorithm. The practicability of the procedure was demonstrated by analysing spiked grape and pineapple samples down to the 1–10 ng/g concentration level.
Analysis of pesticide residues in lettuce by large volume–difficult matrix introduction–gas chromatography–time of flight–mass spectrometry
(LV-DMI-GC-TOF-MS)
Katan Patel, Richard J. Fussell, David M. Goodallb and Brendan J. Keely Analyst, 2003, 128, 1228–1231
<< Read Abstract >>
A multi-residue method is described that eliminates the need for a clean-up step and thus allows the rapid determination of pesticides in crude extracts of lettuce. Samples were extracted with a mixture of ethyl acetate, Na2SO4 and NaHCO3 and the crude extracts analysed directly using large volume–difficult matrix introduction (LV-DMI) in combination with gas chromatography–time of flight–mass spectrometry (GC-TOF-MS). The LV-DMI procedure described was evaluated for the analysis of dimethoate, pyrimethanil, chlorothalonil, vinclozolin, furalaxyl and oxadixyl. Satisfactory response was obtained at the lowest calibrated level (LCL) of 0.0025 µg ml–1, with good linearity over the range 0.0025–0.5 µg ml–1(0.005–1.0 mg kg–1 equivalent). Average recoveries between 73 and 118% were obtained at the 0.01–0.5 mg kg–1 levels with RSD values 13%.
Evaluation of large volume-difficult matrix introduction-gas chromatography-time of flight-mass spectrometry (LV-DMI-GC-TOF-MS) for the
determination of pesticides in fruit-based baby foods
K. Patel, R. J. Fussell, D. M. Goodall and B. J. Keely, Food Additives and Contaminants, Vol. 21, No. 7 (July 2004), pp. 658–669
<< Read Abstract >>
The European Union Baby Food Directive (1999/39/EC), which came into force on 1 July 2002, set legal maximum residue levels at 0.01 mg kg-1 for all pesticides in baby foods. The combination of large volume-difficult matrix introduction (LV-DMI) with gas chromatography-time of flight-mass spectrometry (GC-TOF-MS), described herein, provides the analyst with a simple but rapid alternative GC-MS technique for the multiresidue analysis of pesticides in fruit-based baby foods. Samples were extracted with ethyl acetate in the presence of Na2SO4 and NaHCO3 and the crude extracts were analysed directly using LV-DMI-GC-TOF-MS. The best overall results (98 pesticides quantified satisfactorily at a spiking level of 0.01 mg kg-1) were obtained by analysis of concentrated extracts (2.5 g crop ml-1) using a 30-m column, with a chromatographic run time of 25 min. A good signal-to-noise ratio was obtained at the lowest calibrated level (0.0125 µg ml-1), with excellent linearity achieved over the range 0.0125-0.25 µg ml-1 (equivalent to 0.005-0.1 mg kg-1). Average recoveries for the analysis of five replicate determinations at a spiking level of 0.01 mg kg-1 were between 79 and 114% with relative standard derivations generally less than 20%.
Use of automated direct sample introduction with analyte protectants in the GC–MS analysis of
pesticide residues
Tomas Èajka, Kateøina Mastovska, Steven J. Lehotay, Jana Hajslova. J. Sep. Sci. 2005, 28, 1048–1060
<< Read Abstract >>
Automated large-volume direct sample introduction, or difficult matrix introduction (DMI), was investigated in the determination of 44 pesticide residues possessing a wide range of physico-chemical properties (volatility, polarity, pK(a)) in fruit-based baby food by means of gas chromatography-mass spectrometry (GC-MS) with a quadrupole mass analyzer. DMI has advantages over traditional injection because large volumes (up to 30 microL) of potentially dirty sample extracts can be injected into the GC-MS, but nonvolatile matrix components that would normally contaminate the inlet are removed after every injection. The extra matrix and glass surfaces involved in DMI, however, make the system more prone to the matrix-induced chromatographic enhancement effect, which adversely affects quantification of several pesticides. To overcome this problem, matrix-matched calibration standards and/or the use of analyte protectants were applied in the DMI approach, and the analysis of extracts was also compared before and after undergoing clean-up by dispersive solid-phase extraction. For best quantification, clean-up was still needed, and the combination of matrix-matching with analyte protectants gave the most reproducible results. Depending on the application, however, the addition of analyte protectants (a mixture of 3-ethoxy-1,2-propanediol, L-gulonic acid 3-lactone, and D-sorbitol) to sample extracts and calibration standards in solvent (non-matrix matched), gave satisfactory quantification for most of the 44 pesticides tested. The lowest calibration levels for 34 of the 44 pesticides were < or = 10 ng/g, which meets the standard required by the European Union Baby Food Directive (2003/13/EC).
Automated DMI for screening of cosmetic products
Erwin Kaal, Hans-Gerd Janssen, University ofAmsterdam and Mitsuhiro Kurano, ATAS GL International Shimadzu News, 1/2006 page 6-8.
Application of direct thermal desorption gas chromatography and comprehensive twodimensional
gas chromatography coupled to time of flight mass spectrometry for analysis of organic compounds in ambient aerosol particles
Jurgen Schnelle-Kreis, Werner Welthagen, Martin Sklorz, Ralf Zimmermann. J. Sep. Sci. 2005, 28, 1648–1657
<< Read Abstract >>
Semivolatile organic compounds (SVOC) associated with ambient particles smaller than 2.5 m (PM2.5) were determined in the city of Augsburg, Germany. Daily samples were collected at a central monitoring station from late summer 2002 to spring 2005. SVOC were analysed by direct thermal desorption (DTD)-GC and comprehensive 2-D GC coupled to TOF MS (DTD-GC-TOF MS and DTD-GC×GC-TOF MS). Two hundred compounds were quantified and semi-quantified on a daily basis by DTD-GC-TOF MS. n-Alkanes, n-alkan-2-ones, n-alkanoic acid methyl esters, acetic acid esters, n-alkanoic acid amides, nitriles, linear alkylbenzenes and 2-alkyl-toluenes, hopanes, PAH, alkylated PAH and oxidised PAH, and several compounds that are not grouped in homologous rows or compound classes were determined. Changes in concentration and pattern of several target compounds as well as methodological advantages and restrictions of DTD-GC-TOF MS are briefly discussed. DTD-GC-TOF MS analysis provided data particularly suited for source receptor modelling and epidemiological time series studies on the health effects of ambient PM. GC×GC enhances chromatographic resolution of PM samples and therefore amplifies the peak identification capabilities of the TOF MS.
Analysis of particle-associated semi-volatile aromatic and aliphatic hydrocarbons in urban particulate matter on a daily basis
Jurgen Schnelle-Kreis, Martin Sklorz, Anette Peters,Josef Cyrysb, Ralf Zimmermann. Atmospheric Environment 39 (2005) 7702–7714.
<< Read Abstract >>
PM2.5 Particle-associated semi-volatile organic compounds (SVOC) were determined in the city of Augsburg, Germany. Daily samples were collected at a central monitoring station from late summer to late autumn 2002. The concentrations of polycyclic aromatic hydrocarbons (PAH), oxidized PAH (O-PAH), n-alkanes, hopanes and long chain linear alkylbenzenes were determined by direct thermal desorption-gas chromatography-time of flight mass spectrometry (DTD-GC-TOFMS). Additionally, PM2.5 particle mass and number concentrations were measured. The sampling campaign can be divided into two parts, distinguished by a lower temperature level in the second part of the campaign. The particulate mass concentration showed no significant changes, whereas most of the SVOC had significant higher mean and peak concentrations in the colder period. The analysis of the data showed an increased influence of non-traffic sources in the colder period, reflected by a weak shift in the PAH profile and a significant shift in the hopane pattern. Statistical analysis of the inter-group correlations was carried out. Eight clusters partly representing different sources of the aerosol have been identified.
Organische Verbindungen in Feinstaub (German language)
Nachrichten aus der Chemie, 54, Juni 2006, 676
Analysis of pesticide residues in agricultural products using automated Liner Exchange Difficult Matrix
Introduction (LINEX-DMI) technique coupled to Gas Chromatography/ Mass Spectrometry (GC/MS)
Poster from Y. Takei, K. Iijima, M. Saka
Automated difficult matrix introduction (DMI) for screening of washing powder with GCMS/olfactometryolfactometry
Poster ISEO 2006
Automatic liner exchange with the new LINEX system
Shimadzu news 2/2006 page 25
|
|
print