GERSTEL GmbH and Co. KG

Mülheim (Ruhr), Germany

GERSTEL GmbH and Co. KG

Mülheim (Ruhr), Germany
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Sonibare O.O.,Johannes Gutenberg University Mainz | Sonibare O.O.,University of Mainz | Sonibare O.O.,University of Ibadan | Huang R.-J.,Johannes Gutenberg University Mainz | And 6 more authors.
Journal of Analytical and Applied Pyrolysis | Year: 2014

A recently discovered fossil resin from Koroglu Mountain in Turkey has been analyzed by gas chromatography-mass spectrometry and pyrolysis gas chromatography-mass spectrometry to determine its structural class and botanical origin. The sesqui- and diterpenoids contained in the amber extract were used as chemosystematic markers when compared with terpenoids in extant conifers. The pyrolysis products were dominated by labdanoid derived bicyclic products together with succinic acid indicating Class Ia type amber. The biomarker compositions of the resin comprise mainly sesqui- and diterpenoids, and lack triterpenoids. This distribution suggests a gymnosperm, and more specifically a conifer source. The exclusive presence of abietane- and labdane-type diterpenoids together with the absence of phenolic diterpenoids strongly suggest that the resin was derived from Pinaceae. However, the presence of methyl-16,17-dinor callitrisate in the pyrolysate also suggests that Cupressaceae cannot be excluded as a possible source for the amber. © 2013 Elsevier B.V. All rights reserved.


Lerch O.,GERSTEL GmbH and Co. KG | Temme O.,Heinrich Heine University Düsseldorf | Daldrup T.,Heinrich Heine University Düsseldorf
Analytical and Bioanalytical Chemistry | Year: 2014

The analysis of opioids, cocaine, and metabolites from blood serum is a routine task in forensic laboratories. Commonly, the employed methods include many manual or partly automated steps like protein precipitation, dilution, solid phase extraction, evaporation, and derivatization preceding a gas chromatography (GC)/mass spectrometry (MS) or liquid chromatography (LC)/MS analysis. In this study, a comprehensively automated method was developed from a validated, partly automated routine method. This was possible by replicating method parameters on the automated system. Only marginal optimization of parameters was necessary. The automation relying on an x-y-z robot after manual protein precipitation includes the solid phase extraction, evaporation of the eluate, derivatization (silylation with N-methyl-N- trimethylsilyltrifluoroacetamide, MSTFA), and injection into a GC/MS. A quantitative analysis of almost 170 authentic serum samples and more than 50 authentic samples of other matrices like urine, different tissues, and heart blood on cocaine, benzoylecgonine, methadone, morphine, codeine, 6-monoacetylmorphine, dihydrocodeine, and 7-aminoflunitrazepam was conducted with both methods proving that the analytical results are equivalent even near the limits of quantification (low ng/ml range). To our best knowledge, this application is the first one reported in the literature employing this sample preparation system. © 2014 Springer-Verlag Berlin Heidelberg.


Ochiai N.,GERSTEL K.K. | Sasamoto K.,GERSTEL K.K. | Hoffmann A.,GERSTEL GmbH and Co. KG | Okanoya K.,ITO EN Ltd
Journal of Chromatography A | Year: 2012

A method for analysis of a wide range of odor compounds in aqueous samples at sub-ngmL -1 to μgmL -1 levels was developed by full evaporation dynamic headspace (FEDHS) and gas chromatography-mass spectrometry (GC-MS). Compared to conventional DHS and headspace solid phase microextraction (HS-SPME), FEDHS provides more uniform enrichment over the entire polarity range for odor compounds in aqueous samples. FEDHS at 80°C using 3L of purge gas allows complete vaporization of 100μL of an aqueous sample, and trapping and drying it in an adsorbent packed tube, while providing high recoveries (85-103%) of the 18 model odor compounds (water solubility at 25°C: log0.54-5.65mgL -1, vapor pressure at 25°C: 0.011-3.2mmHg) and leaving most of the low volatile matrix behind. The FEDHS-GC-MS method showed good linearity (r 2>0.9909) and high sensitivity (limit of detection: 0.21-5.2ngmL -1) for the model compounds even with the scan mode in the conventional MS. The feasibility and benefit of the method was demonstrated with analyses of key odor compounds including hydrophilic and less volatile characteristics in beverages (whiskey and green tea). In a single malt whiskey sample, phenolic compounds including vanillin could be determined in the range of 0.92-5.1μgmL -1 (RSD<7.4%, n=6). For a Japanese green tea sample, 48 compounds including 19 potent odorants were positively identified from only 100μL of sample. Heat-induced artifact formation for potent odorants was also examined and the proposed method does not affect the additional formation of thermally generated compounds. Eighteen compounds including 12 potent odorants (e.g. coumarin, furaneol, indole, maltol, and pyrazine congeners) were determined in the range of 0.21-110ngmL -1 (RSD<10%, n=6). © 2012 Elsevier B.V.


Ochiai N.,GERSTEL K.K. 1 3 1 Nakane | Tsunokawa J.,GERSTEL K.K. 1 3 1 Nakane | Sasamoto K.,GERSTEL K.K. 1 3 1 Nakane | Hoffmann A.,GERSTEL GmbH and Co. KG
Journal of Chromatography A | Year: 2014

A novel multi-volatile method (MVM) using sequential dynamic headspace (DHS) sampling for analysis of aroma compounds in aqueous sample was developed. The MVM consists of three different DHS method parameters sets including choice of the replaceable adsorbent trap. The first DHS sampling at 25°C using a carbon-based adsorbent trap targets very volatile solutes with high vapor pressure (>20kPa). The second DHS sampling at 25°C using the same type of carbon-based adsorbent trap targets volatile solutes with moderate vapor pressure (1-20kPa). The third DHS sampling using a Tenax TA trap at 80°C targets solutes with low vapor pressure (<1kPa) and/or hydrophilic characteristics. After the 3 sequential DHS samplings using the same HS vial, the three traps are sequentially desorbed with thermal desorption in reverse order of the DHS sampling and the desorbed compounds are trapped and concentrated in a programmed temperature vaporizing (PTV) inlet and subsequently analyzed in a single GC-MS run. Recoveries of the 21 test aroma compounds for each DHS sampling and the combined MVM procedure were evaluated as a function of vapor pressure in the range of 0.000088-120kPa. The MVM provided very good recoveries in the range of 91-111%. The method showed good linearity (r2>0.9910) and high sensitivity (limit of detection: 1.0-7.5ngmL-1) even with MS scan mode. The feasibility and benefit of the method was demonstrated with analysis of a wide variety of aroma compounds in brewed coffee. Ten potent aroma compounds from top-note to base-note (acetaldehyde, 2,3-butanedione, 4-ethyl guaiacol, furaneol, guaiacol, 3-methyl butanal, 2,3-pentanedione, 2,3,5-trimethyl pyrazine, vanillin, and 4-vinyl guaiacol) could be identified together with an additional 72 aroma compounds. Thirty compounds including 9 potent aroma compounds were quantified in the range of 74-4300ngmL-1 (RSD<10%, n=5). © 2014 The Authors.


Ochiai N.,GERSTEL K.K. | Sasamoto K.,GERSTEL K.K. | Tsunokawa J.,GERSTEL K.K. | Hoffmann A.,GERSTEL GmbH and Co. KG | And 2 more authors.
Journal of Chromatography A | Year: 2015

An extension of multi-volatile method (MVM) technology using the combination of a standard dynamic headspace (DHS) configuration, and a modified DHS configuration incorporating an additional vacuum module, was developed for milliliter injection volume of aqueous sample with full sample evaporation. A prior step involved investigation of water management by weighing of the water residue in the adsorbent trap. The extended MVM for 1mL aqueous sample consists of five different DHS method parameter sets including choice of the replaceable adsorbent trap. An initial two DHS sampling sets at 25°C with the standard DHS configuration using a carbon-based adsorbent trap target very volatile solutes with high vapor pressure (>10kPa) and volatile solutes with moderate vapor pressure (1-10kPa). Subsequent three DHS sampling sets at 80°C with the modified DHS configuration using a Tenax TA trap target solutes with low vapor pressure (<1kPa) and/or hydrophilic characteristics. After the five sequential DHS samplings using the same HS vial, the five traps are sequentially desorbed with thermal desorption in reverse order of the DHS sampling and the desorbed compounds are trapped and concentrated in a programmed temperature vaporizing (PTV) inlet and subsequently analyzed in a single GC-MS run. Recoveries of 21 test aroma compounds in 1mL water for each separate DHS sampling and the combined MVM procedure were evaluated as a function of vapor pressure in the range of 0.000088-120kPa. The MVM procedure provided high recoveries (>88%) for 17 test aroma compounds and moderate recoveries (44-71%) for 4 test compounds. The method showed good linearity (r 2 >0.9913) and high sensitivity (limit of detection: 0.1-0.5ngmL-1) even with MS scan mode. The improved sensitivity of the method was demonstrated with analysis of a wide variety of aroma compounds in brewed green tea. Compared to the original 100μL MVM procedure, this extension to 1mL MVM allowed detection of nearly twice the number of aroma compounds, including 18 potent aroma compounds from top-note to base-note (e.g. 2,3-butanedione, coumarin, furaneol, guaiacol, cis-3-hexenol, linalool, maltol, methional, 3-methyl butanal, 2,3,5-trimethyl pyrazine, and vanillin). Sensitivity for 23 compounds improved by a factor of 3.4-15 under 1mL MVM conditions. © 2015.


David F.,Research Institute for Chromatography RIC | Tienpont B.,Research Institute for Chromatography RIC | Devos C.,Research Institute for Chromatography RIC | Lerch O.,GERSTEL GmbH and Co. KG | Sandra P.,Research Institute for Chromatography RIC
Journal of Chromatography A | Year: 2013

Laboratories focusing on residue analysis in food are continuously seeking to increase sample throughput by minimizing sample preparation. Generic sample extraction methods such as QuEChERS lack selectivity and consequently extracts are not free from non-volatile material that contaminates the analytical system. Co-extracted matrix constituents interfere with target analytes, even if highly sensitive and selective GC-MS/MS is used. A number of GC approaches are described that can be used to increase laboratory productivity. These techniques include automated inlet liner exchange and column backflushing for preservation of the performance of the analytical system and heart-cutting two-dimensional GC for increasing sensitivity and selectivity. The application of these tools is illustrated by the analysis of pesticides in vegetables and fruits, PCBs in milk powder and coplanar PCBs in fish. It is demonstrated that considerable increase in productivity can be achieved by decreasing instrument down-time, while analytical performance is equal or better compared to conventional trace contaminant analysis. © 2013 Elsevier B.V.

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