## 2 Analytical Strategies for Authentication and Quality Control
### Chromatographic and Hyphenated Techniques
Unsupervised (hierarchical cluster analysis and PCA) and supervised (PLS-DA and support vector machine) pattern recognition tools were then used to examine the fingerprints. This untargeted approach is considered to provide greater discriminating power than the targeted one, as it can exploit the entire information included in the raw profile of samples. Unlike spectroscopic techniques, which often allow analysis after minimal sample handling, for chromatographic methods, a very crucial part is the selection of appropriate sample-handling procedures. In many cases, in fact, the direct analysis of samples may be hindered by interfering substances, low analyte concentration or specific sample characteristics that require preparatory steps of cleaning, concentration and/or derivatization. Some authors compared the profile of volatiles and semi-volatiles contained in grape mark spirits by GC-TOF-MS analysis after previous extraction by dispersive liquid-liquid microextraction (DLLME) or SPME. The study highlighted that the DLLME extraction technique was able to provide higher responses than SPME for most substances. Two relevant aspects to consider in the application of DLLME, especially in routine analysis, are the use of chlorinated solvents and the difficulties in automating the procedure [57]. Table 2 presents an overview of the main features of the above-mentioned studies on chromatographic and hyphenated techniques for the authentication of Gr and WB. \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Samples** & **Discriminating Parameters** & **Method of Analysis** & **Data Analysis** & **Results** & **References** \\ \hline
8 spirit drinks (sauo-deve de de & Determination of 16 volatile & & & \\ marc, armagnac, rhum, & congers (acetaldehyde, ethyl) & & & \\ calvados, grape marc & formate, & & & \\ calvados, grape marc & ethyl acetate, acetal, methanol, & & & \\ disallitude, brandy, whisky and & pulyan2-cl, open-1-cl, & Fast GC-FID. high-speed & Determination of & For all analytes: \\ cogn2 & -4 vites (fortified & & \\ \(2\)-methylpropan1-cl, bottan-1-cl, & Fast GC-FID. high-speed & Determination of & For all analytes: \\  & \begin{table}
\begin{tabular}{l l l l l} \hline
**Samples** & **Discriminating Parameters** & **Method of Analysis** & **Data Analysis** & **Results** & **References** \\ \hline  & & & & & PLS-DA average correct classification \\  & & & & rate: 94.3\% (cross-validation) and 100\% \\
82 spirt drinks (60 Grappa & & HS-SPME/GC-MS & & (external validation). \\ samples, 4 grain spirits and & & SPHT drink category & SPME/50/30 mm & & PLS-DA, VIP scores \\
18 fruit marc spirits) & & DVB/CAR/PDMS & & PLS-DA, SIMCA analysis specificity and \\  & & & DVB/CAR/PDMS & & sensitivity of 92.9\% and 87.5\%, \\  & & & DVB/CAR/PDMS & & respectively, in cross-validation and \\  & & & & 100\% and 33.3\%, respectively, in \\  & & & & & external validation. \\ \hline  & & & SPME-GC/MS (for the & & \\  & & & determination of the & & \\  & & & volatile fraction). & & \\
34 spirt drinks (23 Grappa & & Characterization of the profile of & & \\  & & volatile and non-volatile & & fingerprint determination & \\  & & compounds in Grappa spirits for & of the non-volatile fraction. & & \\  & & & quality control & MALL-TOFMS/MS (for & \\  & & & the identification of & \\  & & & molecules of the & \\  & & & non-volatile fraction) & \\ \hline  & & & HS-SPME/GC-MS, HS- & & \\
1 Grappa & & Characterization of volatile profile & SPME-GC/NGC-To-MS & & \\  & & for quality control & SPME & \\  & & & DVB/CAR/PDMS, 50/30 & & HS-SPME/GC-MS. \\  & & & & \\  & & & & \\  & & & & \\ \hline  & & & GC-FID (for the & \\  & & determination of higher & & \\  & & alcohols and acetic acid), & & PCA, HCA analysis: discrimination of & \\  & & & GC-MS (for the & the two groups of grape marc spirits on \\  & & & determination of esters, & the basis of chemical differences between \\  & & & terpenes, lactones and & their distillates. \\ \hline \end{tabular}
\end{table}