Rapid tool for assessment of C13 norisoprenoids in wines

Two novel methodologies for quantification of C(13) norisoprenoids in wines were developed. The first methodology, method A (reference method) was based on the headspace solid-phase microextraction combined with gas chromatography-quadrupole mass spectrometry operating in selected ion monitoring mode (HS-SPME-GC-qMS-SIM). This methodology allowed to select the GC conditions for an adequate chromatographic resolution of wine components. The second methodology, method B (rapid method) was based on the HS-SPME-GC-qMS-SIM, using GC conditions that allowed to obtain a C(13) norisoprenoid volatile signature. In the later, the GC capillary column of 30 m at 220 degrees C was used acting as a transfer line of the components sorbed by the SPME coating fibre to the mass spectrometer, which acts as a sensor for m/z fragments 142 and 192. It does not require any pre-treatment of the sample, and the C(13) norisoprenoid composition of the wine was evaluated based on the chromatographic profile and specific m/z fragments, without complete chromatographic separation of its components. For quantification purposes, external calibration curves were constructed with beta-ionone chemical standard. Calibration curves with regression coefficient (r(2)) of 0.9940 and 0.9968, RSD of 1.08% and 12.51%, and detection limits of 1.10 and 1.57 microg L(-1) were obtained for methods A and B, respectively. These methodologies were applied to seventeen white and red table wines. Two vitispirane isomers (158-1529 microg L(-1)) and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) (6.42-39.45 microg L(-1)) were quantified. The data obtained for vitispirane isomers and TDN using the two methods were highly correlated (r(2) of 0.9756 and 0.9630, respectively). Associated to the fast and robust character of the proposed rapid method B and considering the extraction time, it is important to focus its selectivity and potential applicability if specific m/z fragments would be established for new analytes.