Cannabis sativa L. is an herbaceous plant belonging to the family of Cannabaceae. It is classified into three different chemotypes based on the different cannabinoids profile. In particular, fiber-type cannabis (hemp) is rich in cannabidiol (CBD) content. In the present work, a rapid nano liquid chromatographic method (nano-LC) was proposed for the determination of the main cannabinoids in Cannabis sativa L. (hemp) inflorescences belonging to different varieties. The nano-LC experiments were carried out in a 100 µm internal diameter capillary column packed with a C18 stationary phase for 15 cm with a mobile phase composed of ACN/H2O/formic acid, 80/19/1% (v/v/v). The reverse-phase nano-LC method allowed the complete separation of four standard cannabinoids in less than 12 min under isocratic elution mode. The nano-LC method coupled to ultraviolet (UV) detection was validated and applied to the quantification of the target analytes in cannabis extracts. The nano-LC system was also coupled to an electrospray ionization-mass spectrometry (ESI-MS) detector to confirm the identity of the cannabinoids present in hemp samples. For the extraction of the cannabinoids, three different approaches, including dynamic maceration (DM), ultrasound-assisted extraction (UAE), and an extraction procedure adapted from the French Pharmacopeia's protocol on medicinal plants, were carried out, and the results achieved were compared.
Nano-liquid chromatography and conventional HPLC were used for the separation of diastereomers of (+)-catechin-ethyl-malvidin-3-glucoside. Those bridged anthocyanin dyes were obtained by reaction of (+)-catechin with malvidin-3-glucoside in the presence of acetaldehyde. Both diastereomers were isolated with semipreparative chromatography and their structures were confirmed by nuclear magnetic resonance and mass spectrometry. In-laboratory prepared capillary columns packed with fully porous particles Chromosphere C18, dp=3μm, core-shell particles Kinetex C18, dp=2.6μm (100μm i.d.) and monolithic column Chromolith CapRod (100μm i.d.) were used for the separation of (+)-catechin, malvidin-3-glucoside and both diastereomers. Chromosphere C18 stationary phase provided the best chromatographic performance. Mobile phase containing water:acetonitrile (80:20) acidified with trifluoroacetic acid (0.1%, v/v/v) was used in an isocratic elution mode with a flow rate of 360nLmin(-1). Separation of studied compounds was achieved in less than 7min under optimized conditions. The nano-liquid chromatographic method and a conventional HPLC one using the same fully porous particles (Chromosphere C18, 3μm, 100mm×4.6mm) were compared providing higher separation efficiency with the first analytical method and similar selectivity. A better peak symmetry and higher resolution of the studied diastereomers was achieved by conventional chromatography. Nevertheless, nano-liquid chromatography appeared to be useful for the separation of complex anthocyanin dyes and can be utilized for their analysis in plant and food micro-samples. The developed method was used for analysis of red wine grape pomace.
- MeSH
- acetaldehyd chemie MeSH
- acetonitrily chemie MeSH
- analýza potravin metody MeSH
- anthokyaniny chemie MeSH
- glukosidy chemie MeSH
- hmotnostní spektrometrie MeSH
- katechin chemie MeSH
- poréznost MeSH
- Vitis chemie MeSH
- vysokoúčinná kapalinová chromatografie * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
A new method for the simultaneous separation of cocaine and four metabolites in urine by CE-ESI-MS via a pressurized nanoliquid junction interface was developed. The resolution of cocaine, cocaethylene, benzoylecgonine, norcocaine, and ecgonine methyl ester was achieved in a polyvinyl-alcohol-coated capillary with 75 μm id × 50 cm total length, using a 15 mM ammonium formate electrolyte solution (pH 9.5) in less than 15 min. In addition, to enhance sensitivity, a field-amplified sample injection (FASI) was evaluated in terms of injection time and sample solvent composition. The limits of detection achieved with the FASI method ranged from 1.5 to 10 ng/mL for all the compounds. The detection of the studied compounds was performed using an ion-trap mass spectrometer in a positive ionization mode. A mixture of methanol:water (80:20 v/v) containing 0.1% v/v of formic acid was employed as spray liquid and delivered at ~200 nL/min. Under optimal CE-MS conditions, linearity was assessed in the concentration range of interest for all analytes with correlation coefficients r² ≥ 0.9913. Intra- and inter-day precision provided a relative standard deviation lower than 1.54% for migration times and lower than 12.15% for peak areas. Finally, urine samples, spiked with the standard mixture, were extracted using a solid-phase extraction procedure and injected under FASI conditions, providing recoveries from 80% to 94% for all analytes.
- MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací přístrojové vybavení metody MeSH
- kokain metabolismus moč MeSH
- koncentrace vodíkových iontů MeSH
- lidé MeSH
- nanotechnologie přístrojové vybavení metody MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A pressurized liquid junction nanoelectrospray interface was designed and optimized for reliable on-line CE-MS coupling. The system was constructed as an integrated device for highly sensitive and selective analyses of proteins and peptides with the separation and spray capillaries fixed in a pressurized spray liquid reservoir equipped with the electrode for connection of the electrospray potential. The electrode chamber on the injection side of the separation capillary and the spray liquid reservoir were pneumatically connected by a Teflon tube filled with pressurized nitrogen. This arrangement provided precisely counterbalanced pressures at the inlet and outlet of the separation capillary. The pressure control system was driven by an electrically operated valve and maintained the optimum flow rate for the electrospray stability. All parts of the interface being in contact with the CEBGE, spray liquid and/or sample were made of glass or Teflon. The use of these materials minimized the electrospray chemical noise often caused by plastic softeners or material degradation. During optimization, the transfer of the separated zones between the separation and electrospray capillaries was monitored by UV absorbance and contactless conductivity detectors placed at the outlet of the separation capillary and inlet of the electrospray tip, respectively. This arrangement allowed independent monitoring of the effects of pressure, CE voltage and geometry of the liquid junction on the spreading and dilution of the separated zones after passage through the interface.
