# Resveratrol: A Review on the Biological Activity and Applications
## 18 UHPLC-MS Analysis of \(t\)RSV in Romanian Wines
### Uhplc-Ms Analysis  
The UHPLC-MS analysis of \(t\)RSV in wine samples was conducted using a Waters Arc System coupled with a Waters QDa detector. Initially, all samples were diluted five-fold and then filtered through 0.2 \(\upmu\)m filters before being injected into the system, with an injection volume set at 5 \(\upmu\)L. The mobile phase comprised two components: (A) was 0.1% formic acid in water, and (B) was 0.1% formic acid in acetonitrile. The flow rate was maintained at 0.8 mL/min. The gradient program was as follows: from 0 to 1.8 min, (B) increased from 2% to 9%; from 1.8 to 4 min, (B) held steady at 9%; from 4 to 10 min, (B) rose from 9% to 30%; from 10 to 15 min, (B) escalated from 30% to 90% and was maintained at 90% until 16 min; from 16 to 17 min, (B) rapidly decreased back to 2% for re-equilibration. The column used was a Waters CORTECS C18 (4.6 \(\times\) 50 mm, 2.7 \(\upmu\)m), with the temperature controlled at 28 \({}^{\circ}\)C and samples maintained at 10 \({}^{\circ}\)C. A 15 min equilibration period was allowed between each injection to ensure consistent performance. The QDa mass spectrometer operated in negative mode, with the capillary voltage set at 0.8 kV and the cone voltage at 15 V. Mass spectra were acquired in the range of \(m/z\) 100-400, with selected ion recording (SIR) at \(m/z\) 227 for the specific quantification of \(t\)RSV, providing a robust and sensitive method for analyzing the presence and concentration of this compound in the wine samples [262; 263; 264]. Our study included both white (W1 and W3) and red (W2 and W4) varieties to evaluate the presence and concentration of \(t\)RSV. The calibration curve parameters, indicative of the method's current performance, are detailed, providing insight into the potential for precise quantification. It is important to note that while this analysis offers valuable initial data, the method is undergoing further validation to refine its accuracy and reliability. The results herein serve as a foundation for subsequent validation efforts and offer an early look at \(t\)RSV levels in these wines, contributing to the broader understanding of its distribution in Romanian viniculture. The calibration curve (Figure 2) parameters presented in Table 1 demonstrate a robust analytical method for the quantification of \(t\)RSV. The wide linearity range of 15.259 to 244.141 ng/mL indicates that the method is capable of accurately measuring \(t\)RSV across a range of concentrations that are relevant for wine samples. This range comfortably exceeds the expected concentration levels in typical wine samples, allowing for precise quantification even in wines with lower \(t\)RSV content. \(R^{2}\) of 0.9979 reflects a high degree of linearity, suggesting that the response is directly proportional to the concentration over the range tested. This is critical for ensuring that the quantification is reliable and that the method can be used confidently for routine analysis. The equation of the calibration curve, \(Y=181.7X-197.6\), provides the relationship between the instrument's response and the concentration of \(t\)RSV. The positive slope (181.7) signifies a strong response to increasing concentrations, while the intercept (\(-197.6\)) is relatively small compared to the slope, indicating minimal background noise or interference. LOD and LOQ are also indicators of the method's sensitivity. With a LOD of 16.197 ng/mL and a LOQ of 49.081 ng/mL, the method is sensitive enough to detect and quantify even small amounts of \(t\)RSV. This is particularly important for scientific and regulatory purposes where it is necessary to detect all ranges of concentrations present in various wine samples. The UHPLC chromatogram presents a distinct peak corresponding to the pure \(t\)RSV reference sample. The specificity of the peak is enhanced by the MS detection of the \(m/z\) 227 molecular ion, characteristic of \(t\)RSV.