## 2 Results and Discussion
### Cannabinoids Content
Figure 1 shows the fragmentation pattern of CBDV and CBD. Bearing in mind that this compound has expressed significant physiological activity [33] and that accompanies the CBD as its analogue, it should be included in any quality evaluation of full spectrum CBD oil preparations. Besides, we noticed that when the hemp seed oil was used as matrix, the signal of CBDV augments notably, which means that maybe one portion of CBDV derives from hemp oil, not from flower extract [34]. Bedrolite oil extract (Oil_1) obtained by a recently published procedure [12], is a defined galenic formulation that has been used for distinct therapeutic purposes. It was included in this study as a \"reference material\" from a well-defined starting material (cannabis plant variety) and made using a standardized/authorized preparation procedure. There are at least two reasons to use the cannabinoid profile of Bedrolite oil extract as a reference point in the evaluation of CBD-rich hemp oils. Figure 1: Retrospective data analysis reveals the occurrence of CBDV: full MS-dd-MS\({}^{2}\) chromatogram and relative fragmentation pattern of parent ion (287.20048) obtained in dd-MS\({}^{2}\) acquisition mode. For the comparison, the CBD signal and fragmentation pattern is also presented. Firstly, it can be considered as a _full-spectrum extract_ that preserves the natural ratios of cannabinoids, any impurities that can compromise the experiments should be absent. Secondly, many consumers tend to replace galenic oil preparations (such Bedrolite oil extract) with CBD-rich hemp oil extract, due to the fact that a medical prescription is required for the former. Our study revealed that Bedrolite oil extract contains 0.8% of CBD. This is in agreement with theoretical percentage (0.9%) that should be found in the Bedrolite oil extract: the inflorescence contains 9% of CBD and the dilution ratio during the extraction is 1:10. However, as regards the cannabinoids profile (Table 1), it is evident that the quantities of CBDA, THC, THCA and CBGA are inferior compared with CBD-rich hemp oil extracts. These data are of great importance as they highlight the reduced concentration of all cannabinoids in Bedrolite oil extract compared to CBD hemp oil extract. The reasons for all the abovementioned variations between examined samples are numerous and multiple. The final composition of CBD-rich hemp oil extracts depends on the chemotype and quality of the industrial hemp used, but it is also conditioned by the extraction method applied. Unfortunately, not all producers indicate the extraction method used. Only four declared the use of supercritical CO\({}_{2}\) fluid extraction, which is shown to be the method of choice in that the low temperature and inert atmosphere results in higher CBD yields [18; 19]. However, the main drawback of this technology is its high cost, and it is reasonable to assume that solvent extraction is also used for the inexpensive industrial processing. However, it is questionable if this is a correct choice for a product for human consumption because residual solvents (typically hexane, ethanol, isopropyl alcohol, toluene, benzene, xylene and acetone) may contaminate the final product [32]. Without having complete information on the methods of CBD oils preparation, we investigated the occurrence of the most frequently used extraction solvents as solvent residues. Our analysis revealed the sporadic incidence of acetone (Table 2, ketones section) that is more probably present as a lipid oxidation product rather than as a true residual solvent. Nevertheless, the presence of some volatile compounds that might be considered as problematic impurities from solvents residues was detected (Table 2, miscellaneous section). Namely, the samples Oil_4 and Oil_6 showed the presence of 1,3-dimethylbenzene while in the sample Oil_3, 1,2,4-trimethylbenzene was detected. Those aromatic compounds were not present in galenic preparation (Oil_1).