TY - JOUR T1 - Pitfalls encountered during quantitative determination of 3-alkyl-2-methoxypyrazines in grape must and wine using gas chromatography-mass spectrometry with stable isotope dilution analysis. Comprehensive two-dimensional gas chromatography-mass spectrometry and on-line liquid chromatography-multidimensional gas chromatography-mass spectrometry as potential loopholes. AU - Schmarr,Hans-Georg, AU - Ganss,Sebastian, AU - Koschinski,Stefan, AU - Fischer,Ulrich, AU - Riehle,Carmen, AU - Kinnart,Julian, AU - Potouridis,Theodoros, AU - Kutyrev,Maria, Y1 - 2010/06/25/ PY - 2010/04/08/received PY - 2010/06/16/revised PY - 2010/06/17/accepted PY - 2010/7/20/entrez PY - 2010/7/20/pubmed PY - 2011/2/1/medline SP - 6769 EP - 77 JF - Journal of chromatography. A JO - J Chromatogr A VL - 1217 IS - 43 N2 - The analysis of 3-alkyl-2-methoxypyrazines in Vitis vinifera grape must or wine at the low nanogram per liter level failed in several situations when applying a one-dimensional gas chromatographic analysis with mass spectrometric detection (GC-MS). Sample preparation methods such as headspace solid phase microextraction or solid phase extraction were convenient procedures, however lacking extraction selectivity for complex matrices. Analysis by comprehensive two-dimensional gas chromatography with mass spectrometric detection clearly demonstrated the potential for co-elution in such matrices and the risk for erroneous results when applying one-dimensional GC-MS. In one example, matrix problems would have been a challenge even for a comprehensive two-dimensional chromatographic approach with MS detection (GC×GC-MS). A solution to matrix problems was found by protonating the 3-alkyl-2-methoxypyrazines in acidic pH and sample clean-up using solid phase extraction with a mixed-mode polymeric cation-exchange sorbent. Quantification was performed by a stable isotope dilution assay, following analysis by on-line coupled high performance liquid chromatography with multidimensional gas chromatography and detection with mass spectrometry (on-line LC-MDGC-MS). This new approach allowed trace-level analysis of 3-alkyl-2-methoxypyrazines in grape musts and wines and is described for V. vinifera Sauvignon blanc, following 3-alkyl-2-methoxypyrazines concentrations during ripening and in the processed wines. SN - 1873-3778 UR - https://www.unboundmedicine.com/medline/citation/20637469/Pitfalls_encountered_during_quantitative_determination_of_3_alkyl_2_methoxypyrazines_in_grape_must_and_wine_using_gas_chromatography_mass_spectrometry_with_stable_isotope_dilution_analysis__Comprehensive_two_dimensional_gas_chromatography_mass_spectrometry_and_on_line_liquid_chromatography_multidimensional_gas_chromatography_mass_spectrometry_as_potential_loopholes_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0021-9673(10)00836-8 DB - PRIME DP - Unbound Medicine ER -