This study compares alternative approaches for analyzing phytocannabinoids in different plant materials. Three chromatographic analytical methods (ultra-high-performance liquid chromatography with tandem mass spectrometric detection and gas chromatography with mass spectrometric and flame ionization detection) were evaluated regarding selectivity, sensitivity, analytical accuracy, and precision. The performance of the methods was compared and all three methods were demonstrated to be appropriate tools for analyzing phytocannabinoids in cannabis. Gas chromatography coupled with mass spectrometric detection showed slightly better accuracy in determining phytocannabinoid acids, which are often difficult to quantify owing to their limited stability. Aspects of sample preparation, such as material homogenization and extraction, were also considered. A single ultrasonic-assisted ethanolic extraction of dried and powdered plant samples of cannabis was shown to be exhaustive for extracting the samples prior to analysis.
- MeSH
- Cannabis chemie MeSH
- kanabinoidy analýza MeSH
- laboratoře organizace a řízení MeSH
- limita detekce MeSH
- plamínková ionizace metody MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí metody MeSH
- reprodukovatelnost výsledků MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Online coupling of Lab-In-Syringe automated headspace extraction to gas chromatography has been studied. The developed methodology was successfully applied to surface water analysis using benzene, toluene, ethylbenzene, and xylenes as model analytes. The extraction system consisted of an automatic syringe pump with a 5 mL syringe into which all solutions and air for headspace formation were aspirated. The syringe piston featured a longitudinal channel, which allowed connecting the syringe void directly to a gas chromatograph with flame ionization detector via a transfer capillary. Gas injection was achieved via opening a computer-controlled pinch valve and compressing the headspace, upon which separation was initialized. Extractions were performed at room temperature; yet sensitivity comparable to previous work was obtained by high headspace to sample ratio VHS/VSample of 1.6:1 and injection of about 77% of the headspace. Assistance by in-syringe magnetic stirring yielded an about threefold increase in extraction efficiency. Interferences were compensated by using chlorobenzene as an internal standard. Syringe cleaning and extraction lasting over 10 min was carried out in parallel to the chromatographic run enabling a time of analysis of <19 min. Excellent peak area repeatabilities with RSD of <4% when omitting and <2% RSD when using internal standard corrections on 100 μg L-1 level were achieved. An average recovery of 97.7% and limit of detection of 1-2 μg L-1 were obtained in analyses of surface water.
- MeSH
- automatizace MeSH
- benzen analýza izolace a purifikace MeSH
- benzenové deriváty analýza izolace a purifikace MeSH
- limita detekce MeSH
- mikroextrakce na pevné fázi MeSH
- plamínková ionizace metody MeSH
- teplota MeSH
- toluen analýza izolace a purifikace MeSH
- voda chemie MeSH
- xyleny analýza izolace a purifikace MeSH
- Publikační typ
- časopisecké články MeSH
A simple, cost effective, and fast gas chromatography method with flame ionization detection (GC-FID) for simultaneous measurement of ethylene glycol, 1,2-propylene glycol and glycolic acid was developed and validated for clinical toxicology purposes. This new method employs a relatively less used class of derivatization agents - alkyl chloroformates, allowing the efficient and rapid derivatization of carboxylic acids within seconds while glycols are simultaneously derivatized by phenylboronic acid. The entire sample preparation procedure is completed within 10 min. To avoid possible interference from naturally occurring endogenous acids and quantitation errors 3-(4-chlorophenyl) propionic acid was chosen as an internal standard. The significant parameters of the derivatization have been found using chemometric procedures and these parameters were optimized using the face-centered central composite design. The calibration dependence of the method was proved to be quadratic in the range of 50-5000 mg mL(-1), with adequate accuracy (92.4-108.7%) and precision (9.4%). The method was successfully applied to quantify the selected compounds in serum of patients from emergency units.
- MeSH
- chromatografie plynová metody MeSH
- ethylenglykol krev otrava moč MeSH
- glykoláty krev otrava moč MeSH
- lidé MeSH
- plamínková ionizace metody MeSH
- propylenglykol krev otrava moč MeSH
- sérum chemie MeSH
- studie případů a kontrol MeSH
- toxikologie metody MeSH
- urgentní zdravotnické služby * MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
To fulfil the requirements of health regulations and water quality, it is necessary to monitor the concentrations of volatile hydrocarbons in water at rather low levels. A simple and rapid GC-FID method utilizing liquid-liquid microextraction with xylene in closed vials for the determination of ten selected volatile chlorinated hydrocarbons in water before and after remediation was developed. The procedure allowed to determine selected hydrocarbons at concentrations 10?20 µg l-1 using 1000-ml samples or 30?50 µg l-1 using 60-ml samples. A significant decrease in the detection limits to 2?20 µg l-1 (for 60-ml samples) was achieved by lowering the noise level after replacing GC gases by higher-purity gases and using 1-chloropropane as internal standard. The determination of CHCl3 and CCl4 at the µg l-1 levels was feasible using an ECD detector. Even lower detection limits can be achieved by modification of the GC injector and by injecting a large volume of the xylene extract.
