## 3 Results
### Cannabinoids in Hemp Oil  
The method developed in this study was applied to the qualitative-quantitative analysis of the main cannabinoids from four samples of hemp oil. The amount of each cannabinoid was calculated using the equation obtained from a freshly prepared calibration curve. The following sequence was injected into the chromatographic system:  
* \(1\times\) blank;
* \(1\times\) Calibration solution 2.5 \(\mu\)g/mL;
* \(1\times\) QC solution;
* \(1\times\) 3000-Fold samples; \begin{table}
\begin{tabular}{c c c} \hline
**Analyte** & **Regression Equation** & **R\({}^{2}\)** \\ \hline CBDV & y = 22,747\(\times\) + 11,129 & 0.9999 \\ \hline CBDA & y = 37,845\(\times\) + 26,076 & 0.9997 \\ \hline CBGA & y = 39,081\(\times\) + 26,087 & 0.9996 \\ \hline CBG & y = 21,367\(\times\) + 11,536 & 0.9999 \\ \hline CBD & y = 21,100\(\times\) + 10,921 & 0.9998 \\ \hline CBN & y = 47,883\(\times\) + 51,955 & 0.9990 \\ \hline \(\Delta\)9-THC & y = 18,904\(\times\) + 14,026 & 0.9997 \\ \hline \(\Delta\)8-THC & y = 17,184\(\times\) + 10,464 & 0.9998 \\ \hline CBC & y = 44,184\(\times\) \(-\) 6791.7 & 0.9998 \\ \hline THCA & y = 34,511\(\times\) \(-\) 7682.5 & 0.9997 \\ \hline \end{tabular}
\end{table} 
Table 4: Results for linearity, regression equation, and R\({}^{2}\) for each analyte. \begin{table}
\begin{tabular}{c c c c c} \hline
**Analyte** & **LOD (\(\mu\)g/mL)** & **LOQ (\(\mu\)g/mL)** & **LOD (mg/g)** & **LOQ (mg/g)** \\ \hline CBDV & 0.70 & 2.12 & 0.21 & 0.64 \\ \hline CBDA & 1.69 & 5.13 & 0.51 & 1.54 \\ \hline CBGA & 1.78 & 5.39 & 0.53 & 1.62 \\ \hline CBG & 0.67 & 2.03 & 0.20 & 0.61 \\ \hline CBD & 0.63 & 1.92 & 0.19 & 0.58 \\ \hline CBN & 3.31 & 10.04 & 0.99 & 3.01 \\ \hline \(\Delta\)9-THC & 0.75 & 2.27 & 0.22 & 0.68 \\ \hline \(\Delta\)8-THC & 0.82 & 2.50 & 0.25 & 0.75 \\ \hline CBC & 1.30 & 3.93 & 0.39 & 1.18 \\ \hline THCA & 1.84 & 5.59 & 0.55 & 1.68 \\ \hline \end{tabular}
\end{table} 
Table 5: Limit of detection (LOD) and limit of quantification (LOQ), determined by the calibration curves in standard units (\(\mu\)g/mL) and sample units (mg/g). * 1\(\times\) QC every 10 samples;
* 1\(\times\) QC after all samples;
* 1\(\times\) Blank;
* 1\(\times\) Wash.  
As system suitability criteria, we chose to verify the accuracy of the 2.5 \(\mathrm{\SIUnitSymbolMicro g}\)/mL calibration solution and QC solution; all the analyzed solutions passed the admissibility criteria (\(\pm\)10%). Concentration in mg/g was calculated by following formula:  
\[C\left(\mathrm{mg/g}\right)=C\left(\mathrm{\SIUnitSymbolMicro g}/\mathrm{mL} \right)\times\mathrm{d/Swg}\times 1000\]  
where C (\(\mathrm{\SIUnitSymbolMicro g}\)/mL) is the concentration extrapolated on the calibration curve, d is dilution factor (300 or 3000), Swg is sample weight in grams, and 1000 represents the transformation factor from \(\mathrm{\SIUnitSymbolMicro g}\) to mg. The main components CBD and CBDA were found in all samples, except two for CBDA in a concentration range of 1.42 to 166.32 mg/g for CBD and 1.62 to 18.80 mg/g for CBD. Other cannabinoids also present in oils were CBDV (2.52 to 14.70 mg/g), CBGA, which was detected in two samples (1.19 to 2.64 mg/g) and as traces in the other two samples, CBG, which was quantified in only one sample (2.13 mg/g) and detected in other three, CBN (4.75 mg/g), which was found in one sample and identified in other three, \(\mathrm{\SIUnitSymbol A}\)9-THC (1.06 to 1.35 mg/g), \(\mathrm{\SIUnitSymbol A}\)8-THC, which was detected only in one sample in too low amount to be quantified, and CBC, which was present in six samples at a lower concentration, suggesting the need to decrease the dilution fold in order to be quantified and THCA (1.80-2.75 mg/g). A more detailed view can be found in Table 6. Representative chromatograms of sample solutions S5 are shown in Figure 2a,b, and the rest of the chromatograms can be reviewed in the Supplementary Materials (Figures S1-S9).