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for the analysis of cannabinoids in bio-matrices are continually improved to achieve best possible sensitivity in their detection and accurate quantification. It has been well documented that CBD cyclizes to Δ9-THC and Δ9-THC isomerizes to Δ8-THC under acidic conditions by means of a Lewis-acid-catalyzed process, causing difficulty in accurate quantification of Δ9-THC in the presence of CBD, of CBD itself and of Δ9-THC itself when these compounds have to be derivatized by acylation. The present paper shows that CBD cyclization and Δ9-THC isomerization can be blocked by tertiary amines or azines, which capture protons appearing in the derivatizing mixture during acylation. The efficiency of the described acylation of CBD depends on the time and temperature of the derivatizing process, whereas the degree of CBD acylation, i.e. the synthesis of mono- or di-acylate CBD derivative, depends on the mutual ratio of the cannabinoid, the acylating agent and the proton binding compound. The way of mono- and di-acyl CBD derivatives formation described in the paper has not been reported yet. The paper contains a comprehensive analytical characterization of two types of CBD acyl derivatives, CBD-TFA and CBD-Ac, obtained by NMR, GC-MS and LC-MS.

The knowledge of compounds stability in the process of sample preparation for analysis and during analysis itself helps assess the accuracy and precision of estimating their concentration in tested samples. The present paper shows that a significant amount of CBD present in the blood/plasma sample analyzed by means of GC transforms in the hot GC injector not only to 9α-hydroxyhexahydrocannabinol, 8-hydroxy-iso-hexahydrocannabinol, delta-9-tetrahydrocannabinol, Δ8-tetrahydrocannabinol, and cannabinol but also to the trifluoroacetic esters of Δ9-THC and Δ8-THC, when trifuoroacetic acid is used as protein precipitation agent. The amount of those newly revealed CBD transformation products depends on the GC injector temperature and on the extrahent type when extracts of the supernatants centrifuged from human plasma samples are analyzed after their preliminary protein precipitation by trifuoroacetic acid. Although trifuoroacetic acid as a protein precipitating agent has many disadvantages, it is quite often used for this purpose due to its very high protein precipitation efficiency. The results presented in the study demonstrate why the use of trifuoroacetic acid for plasma samples deproteinization should be avoided when CBD is determined by GC.

The growing popularity of supplements containing cannabidiol (CBD), mainly CBD oils, in self-medication of humans and the increased interest in this compound in different preclinical and clinical trials stimulates the development of procedures of CBD analysis in plasma for the study of CBD pharmacology in people and animals or in establishing dose–therapeutic effect relationships of this compound. Preliminary removal of protein by its precipitation from plasma is still one of the willingly applied plasma sample preparation methods in many analytical procedures estimating plasma drug concentration, including CBD. The present paper shows that a significant amount of CBD transforms to Δ9-tetrahydrocannabinol (Δ9-THC) in a hot GC injection system when acidic precipitation agents, such as TFA, TCA, HClO4, H2SO4, ZnSO4 or CHCl3, are used for plasma protein precipitation. The transformation degree depends on the temperature of the GC injector, the concentration of the precipitation agent and the incubation time of plasma with the precipitating agent. At the CBD plasma concentration equal to 50 ng/ml, which is approximately the mean level for patients treated for epileptic syndromes, the CBD transformation degree can exceed 20%. For a reliable estimate of CBD in blood plasma, neutral precipitation agents (e.g. ACN, MeOH, acetone) should be used when plasma deproteinization precedes GC analysis. The presented results are important not only for analysts cooperating with pharmacologists and for medicine doctors examining the activity of CBD-containing drugs in the therapeutic process, but also for forensic scientists who may erroneously find innocent people guilty of using marijuana or its preparations.

Methods for the analysis of cannabinoids in bio-matrices are continually being developed, to achieve a proper sensitivity required for their detection and accuracy in their quantification. The presented paper shows that the analytical sensitivity of GC-MS to THC and its metabolites in blood samples can be significantly increase by oleamide (OLA) addition to the examined sample, which evokes the matrix effect of transient character. The magnitude of signal increment resulting from oleamide presence in the examined sample is the greatest for THC metabolites and depends on oleamide concentration in the examined sample. The use of transient matrix effect to increase the sensitivity of the analysis can be applied not only in QuEChERS procedure, which is applied in the described experiments, but also in other blood sample preparation methods. Evoking the transient matrix effect by means of OLA in the experimental analytical quantitation of THC and its metabolites in blood allowed to lower limit of detection (LOD) approximately by 20.5%, 87.6% and 90.1% in the case of THC, THC-OH and THC-COOH, respectively.

This study aimed to evaluate the phenolic profile and biological activity of the extracts from the leaves and fruits of Cotoneaster nebrodensis and Cotoneaster roseus. Considering that miscellaneous species of Cotoneaster are thought to be healing in traditional Asian medicine, we assumed that this uninvestigated species may reveal significant therapeutic properties. Here, we report the simultaneous assessment of chemical composition as well as biological activities (antioxidant, anti-inflammatory, antibacterial, and cytotoxic properties) of tested species. Complementary LC-MS analysis revealed that polyphenols (especially flavonoids and proanthocyanidins) are the overriding phytochemicals with the greatest significance in tested biological activities. In vitro chemical tests considering biological activities revealed that obtained results showed different values depending on concentration, extraction solvent as well as phenolic content. Biological assays demonstrated that the investigated extracts possessed antibacterial properties and were not cytotoxic toward normal skin fibroblasts. Given the obtained results, we concluded that knowledge of the chemical composition and biological activities of investigated species are important to achieve a better understanding of the utilization of these plants in traditional medicine and be useful for further research in their application to treat various diseases, such as skin disorders.

During pyrolysis and several environmental processes, polycyclic aromatic hydrocarbons (PAHs) are altered and O/N/S-derivatives may be formed. The thermal utilization of sewage sludge (SSL) and bio-wastes (e.g. plant materials) towards biochars (BC) may be connected with the formation of both PAHs and their derivatives, known toxic compounds. Their toxicity depends on bioavailability. In the presented studies the effect of pyrolysis temperature on PAHs and their derivatives formation was investigated. The results clearly indicated that temperature (500, 600, and 700 °C) and feedstock (sewage sludges, wheat straw, willow) affected both the amount and type of bioavailable PAHs in biochars. The total content of bioavailable PAHs in SSL-derived BC was higher than in plant-derived BC and ranged from 8.58 to 16.07 ng L−1 for BC obtained from SSL, 1.67–3.53 ng L−1 for straw-derived biochars, and 3.17–3.53 ng L−1 for willow-derived biochars. The percentage of quantified PAHs derivatives in SSL-derived BC was up to 10.3 %. Plant-derived BC were enriched in PAHs derivatives (1-methyl-5-nitronaphthalene, 1-methyl-6-nitronaphthalene, 4H-cyclopenta(def)phenanthrene, and nitropyrene). The increase of the pyrolysis temperature caused an increase in the percentage of PAHs derivatives from 5 % to 37.4 % (500−700 °C) for straw-derived BC whereas decrease to 15 % for willow-derived BC. The presence of toxic compounds such: 1-methyl-5-nitronaphthalene, 1-methyl-6-nitronaphthalene, nitropyrene in plant-derived BC, and B[a]P, nitronaphthalene, 9,10-anthracenedione in SSL-derived BC may significantly limit their agricultural applications.

The quantitative relationship between analytes established by the headspace solid-phase microextraction procedure for multicomponent mixtures depends not only on the character and strength of interactions of individual components with solid-phase microextraction fiber but also on their vapor pressure in the applied headspace solid-phase microextraction system. This study proves that vapor pressure is of minor importance when the sample is dissolved/suspended in a low-volatility liquid of the same physicochemical character as that of the used solid phase microextraction fiber coating. It is demonstrated for mixtures of alcohols, esters, ethers and their selected representatives by applying a headspace solid-phase microextraction system composed of Carbowax fiber and sample solutions in polyethyleneglycol. The observed differences in quantitative relations between components of the examined mixtures established by their direct analysis and by modified headspace solid-phase microextraction are insignificant (Fexp

The paper discusses the matrix effect evoked by oleamide (OLA), a compound frequently found in samples processed and/or stored in lab polypropylene vials or disposable syringes. In the case of many substances a higher response for their samples containing OLA than for net solutions is observed. The analyte signal gain resulting from OLA presence in the examined sample depends on the ratio of OLA concentration to analyte concentration. A characteristic feature of the matrix effect evoked by oleamide is its short duration, which makes the chromatographic data (retention value and signal magnitude of examined compound) repeatable and reproducible. The identified "transient matrix effect" may significantly increase the sensitivity of many analytical procedures employing GC. Evoking the transient matrix effect by means of OLA in the experimental analytical quantitation of cannabidiol in plasma allowed to lower its limit of detection (LOD) by more than 50 %.

Similar quantitative relations between individual constituents of the liquid sample established by its direct injection can be obtained applying Polydimethylsiloxane (PDMS) fiber in the headspace solid phase microextraction (HS-SPME) system containing the examined sample suspended in methyl silica oil. This paper proves that the analogous system composed of sample suspension/emulsion in polyethylene glycol (PEG) and Carbowax fiber allows to get similar quantitative relations between components of the mixture as those established by its direct analysis, but only for polar constituents. It is demonstrated for essential oil (EO) components of savory, sage, mint and thyme, and of artificial liquid mixture of polar constituents. The observed differences in quantitative relations between polar constituents estimated by both applied procedures are insignificant (Fexp

The main limitation in the standard application of head space analysis employing solid phase microextraction (HS-SPME) for the evaluation of plants as sources of essential oils (EOs) are different quantitative relations of EO components from those obtained by direct analysis of EO which was got in the steam distillation (SD) process from the same plant (EO/SD). The results presented in the paper for thyme, mint, sage, basil, savory, and marjoram prove that the quantitative relations of EO components established by HS-SPME procedure and direct analysis of EO/SD are similar when the plant material in the HS-SPME process is replaced by its suspension in oil of the same physicochemical character as that of SPME fiber coating. The observed differences in the thyme EO composition estimated by both procedures are insignificant (F(exp)

Recently, much attention has been given to congener analysis, which can be used to check the possibility of postoffence drinking claims in forensic toxicology. In this type of analysis, the information given by the defendant regarding the type, quantity, and time of consumption of a specific alcoholic beverage is used to calculate theoretically expected congener concentration in the blood and this is compared with the analytically determined concentrations in the blood sample. Many alcoholic drinks aromatized with essential oils of plants and fruits contain a specific congener, for example, anethole in aniseed drinks. The present study describes the GC procedure of anethole analysis in human plasma using SPE as the sample preparation method. The procedure involves the protein precipitation process, which generally degrades the protein-analyte complex, and SPE isolation of anethole from the examined materials. This analytical approach is proposed as a method of choice for the estimation of anethole concentration in human fluids after the consumption of alcoholic beverages and other foods containing the substance. The described method is characterized by a low LOD (8.33 ng/g) and a very high recovery (average recovery 98.37%) of the analyte.

Analytical procedures of complex mixtures frequently involve their initial pre-fractionation to make the analysis easier or possible. Recently, SPE is frequently applied for this purpose. This article discusses the possibility of essential oil's fractionation using SPE with octadecyl modified silica. The presented results show that developed SPE with C-18 sorbent allows for easy and total isolation (100% recovery) of low-molecular oxygen compounds from the remaining compounds, for which the recovery exceeds 95%. The obtained recoveries are satisfactory for preliminary separation of essential oils for analytical and preparative purposes.