## 2 Results and Discussion
### Cannabinoids Content
As can be seen in Table 1, in the majority of the samples the CBDA concentration was found to be negligible compared to the amount of CBD (for example, samples Oil_4 and Oil_15). On the contrary, there were a few samples with a significant amount of CBDA. A striking example is Oil_3, in which the CBDA content exceeded CBD, and only the sum of both forms justified the CBD percentage declared by the producer. Furthermore, it is evident that the label concentration of CBD in Oil_12 is reached only when the sum of both forms is considered, bearing in mind the significant amount of CBDA. Nevertheless, all producers underline that their manufacturing methods yield the so called full spectrum extract, which means that hemp extracts contain different phyto-cannabinoids, including THC, CBN, CBG, THCA, CBGA and others, depending from cannabis strain and extraction method. In order to achieve full-spectrum in a hemp extract, the profile of bioactive compounds that a plant flower contains must be transferred into the extract itself without compromising any aspect of the profile. In comparison with previous works available on cannabis oil [9; 10; 11; 31] we employed a HRMS method that provided more complete information regarding the cannabinoids profile and amount in the oil composition. Actually, besides CBD as a principal cannabinoid, we were able to detect and to quantify the six most significant cannabinoids, including the essential ones (THC, THCA and CBDA) along with quantification of CBN, CBG and CBGA. The obtained results clearly show that 12 out of 14 samples contained THC which is attention-grabbing because of its potential intoxicating activity. The THC content showed the considerable variability in the analysed samples, but was mainly at the levels describable as low (0.2%) [17]. Only one among all THC-positive sample (Oil_6) contained a considerable amount of THC (0.35%), which is matter of concern because the manufacturer declared the product to be THC-free. This result highlights the importance of also specifying the amount of THC or any another intoxicating cannabinoid present in commercialised CBD oils. CBN was quantifiable in the vast majority of samples (except Oil_14). Its detection is of great importance as it is not considered to be a natural cannabinoid but rather an artefact formed by THC oxidation during plant aging, by use of an inadequate extraction procedure or inappropriate storage conditions [32]. Therefore, its determination may assist in the evaluation of the quality of CBD oils with regards to the raw plant material used, extraction method applied and storage. For example, in the sample Oil_13 the quantity of the CBN was more than twice the amount of THC. Considering CBN as a degradation product of THC, it would be better to think through the sum of THC+CBN as a relevant parameter for the evaluation of initial THC concentration in the oil extract. In addition,CBN, though much less psychoactive than THC, express sedative effects [33; 34] which is why its content should be indicated on the label along with THC. It is well known that THC derives from the decarboxylation of tetrahydroocannabinolic acid (THCA) [20], and this is the reason why the amount of THCA was quantified in this study. Our results did not reveal any significant presence of either THCA (Table 1) or cannabigerolic acid (CBGA) which is the precursor of the all other cannabinoid acids. CBGA gives by decarboxylation cannabinoid (CBG) that either was completely absent or present in minor quantities. The quantification of CBGA and CBG did not turn out to be imperative, but their presence could serve as a confirmation that the oil sample contains a natural, full spectrum cannabis extract. Furthermore, employing the retrospective analysis, several other minor \"untargeted\" compounds were detected by means of the Orbitrap (Thermo Fisher Scientific, San Jose, CA, USA) \({}^{\text{\textregistered B}}\) analyser. Among others (data not shown) it is important to highlight the persistent occurrence of CBDV in all analysed samples.