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1.
Heliyon ; 10(7): e27559, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38560135

RESUMO

Ethylene Glycol (EG) and diethylene Glycol (DEG) are two contaminants known to cause various human health problems. These glycols might be present in drug syrups that are based on glycerol, sorbitol, or polyethylene glycol. In late 2022, several batches of cough, antipyretics, and antihistamine syrups were reported to contain toxic levels of EG and DEG in multiple countries; this incident concerned the World Health Organization (WHO). From an analytical perspective, several methods of glycols analysis in pharmaceuticals have been reported in the literature, with the majority being dedicated to raw material analysis. This study aims to develop a selective method capable of evaluating a wide range of paediatric syrups in order to assess the safety of commercially available paediatric syrups currently distributed in the local market. This research introduces a method for determining glycols utilizing gas chromatography-tandem mass spectrometry (GC-MS/MS), which offers significantly higher selectivity than conventional single quadrupole gas chromatography-mass spectrometry (GC-MS). The developed method meets the current International Council for Harmonisation (ICH) guidelines for validation. The absence of any interfering peaks in both the unspiked sample of promethazine syrup and the reference standard solutions proved the method's selectivity. Furthermore, 2,2,2-trichloroethanol was used as an internal standard, and a new GC-MS/MS method was developed to analyze it. The calibration curves for EG and DEG were linear within the selected concentration range of 1-10 µg/mL. The detection limit for both EG and DEG was 400 ng/mL, while the quantification limit was 1 µg/mL. Recovery values for both EG and DEG met the accuracy acceptance criterion. Thus, the developed method proved to be efficient and accurate for determining EG and DEG levels in suspected contaminated syrups.

2.
Anal Bioanal Chem ; 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38568233

RESUMO

Iodoacetic acid (IAA) is a halogenated disinfection by-product of growing concern due to its high cytotoxicity, genotoxicity, endocrine disruptor effects, and potential carcinogenicity. However, the data on distribution and excretion of IAA after ingestion by mammals are still scarce. Here, we developed a reliable and validated method for detecting IAA in biological specimens (plasma, urine, feces, liver, kidney, and tissues) based on modified QuEChERS sample preparation combined with gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS). The detection method for IAA exhibited satisfactory recovery rates (62.6-108.0%) with low relative standard deviations (RSD < 12.3%) and a low detection limit for all biological matrices ranging from 0.007 to 0.032 ng/g. The study showed that the proposed method was reliable and reproducible for analyzing IAA in biological specimens. It was successfully used to detect IAA levels in biological samples from rats given gavage administration. The results indicated that IAA was found in various tissues and organs, including plasma, thyroid, the liver, the kidney, the spleen, gastrointestinal tract, and others, 6 h after exposure. This study provides the first data on the in vivo distribution in and excretion of IAA by mammals following oral exposure.

3.
Biomed Chromatogr ; : e5867, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38558037

RESUMO

Fourteen donepezil-like acetylcholinesterase (AChE) inhibitors from our library were analyzed using reversed-phase thin-layer chromatography to assess their lipophilicity and blood-brain barrier permeability. Compounds possessed N-benzylpiperidine and N,N-diarylpiperazine moieties connected via a short carboxamide or amine linker. Retention parameters RM 0, b, and C0 were considered as the measures of lipophilicity. Besides, logD of the investigated compounds was determined chromatographically using standard compounds with known logPow and logD values at pH 11. Experimentally obtained lipophilicity parameters correlated well with in silico generated results, and the effect of the nature of the linker between two pharmacophores and substituents on the arylpiperazine part of the molecule was observed. As a result of drug-likeness analysis, both Lipinski's rule of five and Veber's rule parameters were determined, suggesting that examined compounds could be potential candidates for further drug development. Principal component analysis was performed to obtain an insight into a grouping of compounds based on calculated structural descriptors, experimentally obtained values of lipophilicity, and AChE inhibitory activity.

4.
Methods Mol Biol ; 2797: 35-46, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38570451

RESUMO

Biochemical and biophysical assays using recombinant RAS require the protein to be in either the active or inactive state. Here we describe methods to exchange the nucleotide present in the purified RAS protein with either GDPßS, GppNHp, or GTP depending on the assay requirement. In addition, we also describe the HPLC method used to validate the exchange process and provide information on the efficiency of the nucleotide exchange.


Assuntos
Proteínas ras , Guanosina Trifosfato/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismo , Guanosina Difosfato
5.
Methods Mol Biol ; 2797: 227-236, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38570463

RESUMO

Guanine nucleotides can be quantitatively analyzed by high-performance liquid chromatography (HPLC). Here we describe an ion-pair reversed-phase HPLC (IP-RP-HPLC)-based method, which enables analyzing GDP and GTP bound to small GTPases immunoprecipitated from cells. The activation status of FLAG-KRAS expressed in HEK293T cells can be investigated with the IP-RP-HPLC method. This method also can be adapted to determine the effects of compounds such as the KRAS/G12C inhibitor sotorasib on the activation status of FLAG-KRAS in the cells.


Assuntos
Nucleotídeos de Guanina , Proteínas Monoméricas de Ligação ao GTP , Humanos , Cromatografia Líquida de Alta Pressão/métodos , Proteínas Proto-Oncogênicas p21(ras)/genética , Células HEK293
6.
Talanta ; 274: 125996, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38574535

RESUMO

Benzoic acid is used as a preservative in processed food, and occasionally in cosmetics and pharmaceuticals, while benzoic acid occurs naturally in, e.g., cranberry and lingonberry. Therefore, the determination of benzoate is of interest for product quality assurance, food safety, and personal health. In this work, a solid-contact benzoate-selective electrode (benzoate-ISE) was developed by utilising poly(3,4-ethylenedioxythiophene) (PEDOT) as solid contact and a solvent polymeric membrane containing a 1,3-bis(carbazolyl)urea derivative as ionophore. The benzoate-ISE was characterised in parallel with an ionophore-free control-ISE by electrochemical impedance spectroscopy and potentiometry. The presence of the ionophore in the membrane improved the selectivity to benzoate. Benzoate-ISEs and control-ISEs were used further to determine the benzoate concentration in cranberry and lingonberry by standard addition. The results obtained with both types of ISEs were compared with those obtained by ion chromatography. The results obtained with benzoate-ISEs were consistent with those obtained with ion chromatography. On the contrary, the control-ISE (without ionophore) gave significantly higher benzoate concentrations, especially in the case of cranberry where the benzoate concentration was low (ca 0.2 g kg-1) compared to lingonberry (ca 1 g kg-1). Hence, the benzoate-selectivity of the ionophore was crucial to obtain a benzoate-ISE that was practically applicable for determination of benzoate concentrations in cranberry and lingonberry.

7.
Talanta ; 274: 126011, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38574537

RESUMO

In this article, we have studied the potential of flexible microtube plasma (FµTP) as ionization source for the liquid chromatography high-resolution mass spectrometry detection of non-easily ionizable pesticides (viz. nonpolar and non-ionizable by acid/basic moieties). Phthalimide-related compounds such as dicofol, dinocap, o-phenylphenol, captan, captafol, folpet and their metabolites were studied. Dielectric barrier discharge ionization (DBDI) was examined using two electrode configurations, including the miniaturized one based on a single high-voltage (HV) electrode and a virtual ground electrode configuration (FµTP), and also the two-ring electrode DBDI configuration. Different ionization pathways were observed to ionize these challenging, non-easily ionizable nonpolar compounds, involving nucleophilic substitutions and proton abstraction, with subtle differences in the spectra obtained compared with APCI. An average sensitivity increase of 5-fold was attained compared with the standard APCI source. In addition, more tolerance with matrix effects was observed in both DBDI sources. The importance of the data reported is not just limited to the sensitivity enhancement compared to APCI, but, more notably, to the ability to effectively ionize nonpolar, late-eluting (in reverse-phase chromatography) non-ionizable compounds. Besides o-phenylphenol ([M - H]-), all the parent species were efficiently ionized through different mechanisms involving bond cleavages through the effect of plasma reagent species or its combination with thermal degradation and subsequent ionization. This tool can be used to figure out overlooked nonpolar compounds in different environmental samples of societal interest through non-target screening (NTS) strategies.

8.
J Chromatogr A ; 1722: 464843, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38574599

RESUMO

Reversed-phase high performance liquid chromatography (RP-HPLC) is the most widely used chromatographic method. In addition to hydrophobic interactions, additional interactions such as electrostatic interactions may participate in the retention behaviour of an analyte. This makes it possible to use RP-HPLC for many types of analyte. We describe a simple method for separating inorganic anions on a C18 column, in which retention of inorganic anions is almost entirely due to electrostatic interactions. This leads to rapid separations as well as higher theoretical plate numbers. We used 2 mM phosphoric acid containing a low concentration of disodium molybdate as the mobile phase, which allows UV detection of non-UV-absorbing anions. With this method, we determined eight inorganic anions including several non-UV-absorbing anions photometrically at 220 nm. The detection limits of the examined eight inorganic anions calculated at a signal-to-noise ratio of 3 were between 0.3 and 10 µM. The detector response was linear over three orders of magnitude of inorganic anion concentration. The proposed RP-HPLC/UV method was successfully applied to determine inorganic anions in some water samples.

9.
J Chromatogr A ; 1722: 464864, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38598890

RESUMO

In this study, a novel piperidinium-sulfonate based zwitterionic hydrophilic monolith was prepared through thermally initiated co-polymerization of a piperidinium-sulfonate monomer 3-(4-((methacryloyloxy)methyl)-1-methylpiperidin-1-ium-1-yl)propane-1-sulfonate (MAMMPS), and a hydrophilic crosslinker N,N'-methylenebisacrylamide (MBA) using n-propanol and H2O as porogenic system. Satisfactory mechanical and chemical stabilities, good repeatability and high column efficiency (120,000 N/m) were obtained on the optimal monolith. The resulting poly(MAMMPS-co-MBA) monolith showed a typical HILIC retention behavior over an ACN content range between 5 and 95 %. Furthermore, this column exhibited good separation performance for various polar compounds. Compared to quaternary ammonium-sulfonate based zwitterionic hydrophilic monolith, i.e. poly(N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl)ammonium betaine-co-MBA), the poly(MAMMPS-co-MBA) monolith displayed stronger retention and better selectivity for the tested phenolic and amine compounds at different pH conditions. Finally, this column was applied for the separation of six sulfonamide antibiotics, and the analytical characteristics of the method were evaluated in terms of precision, repeatability, limits of detection (LOD) and quantitation (LOQ). Overall, this study not only developed a novel HILIC monolithic column, but also proved the potential of piperidinium-sulfonate based zwitterionic chemistry as stationary phase, which further increased the structure diversity of zwitterionic HILIC stationary phases.

10.
J Chromatogr A ; 1722: 464874, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38598893

RESUMO

Hydroxypropyl methyl cellulose (HPMC) is a type of cellulose derivative with properties that render it useful in e.g. food, cosmetics, and pharmaceutical industry. The substitution degree and composition of the ß-glucose subunits of HPMC affect its physical and functional properties, but HPMC characterization is challenging due to its high structural heterogeneity, including many isomers. In this study, comprehensive two-dimensional liquid chromatography-mass spectrometry was used to examine substituted glucose monomers originating from complete acid hydrolysis of HPMC. Resolution between the different monomers was achieved using a C18 and cyano column in the first and second LC dimension, respectively. The data analysis process was structured to obtain fingerprints of the monomers of interest. The results revealed that isomers of the respective monomers could be selectively separated based on the position of substituents. The examination of two industrial HPMC products revealed differences in overall monomer composition. While both products contained monomers with a similar degree of substitution, they exhibited distinct regioselectivity.

11.
J Chromatogr A ; 1722: 464890, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38598892

RESUMO

The rapidly growing market of monoclonal antibodies (mAbs) within the biopharmaceutical industry has incentivised numerous works on the design of more efficient production processes. Protein A affinity chromatography is regarded as one of the best processes for the capture of mAbs. Although the screening of Protein A resins has been previously examined, process flexibility has not been considered to date. Examining performance alongside flexibility is crucial for the design of processes that can handle disturbances arising from the feed stream. In this work, we present a model-based approach for the identification of design spaces, enhanced by machine learning. We demonstrate its capabilities on the design of a Protein A chromatography unit, screening five industrially relevant resins. The computational results favourably compare to experimental data and a resin performance comparison is presented. An improvement on the computational time by a factor of 300,000 is achieved using the machine learning aided methodology. This allowed for the identification of 5,120 different design spaces in only 19 h.

12.
J Chromatogr A ; 1722: 464889, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38598894

RESUMO

In this paper, three imidazole- and C18- bifunctional silica stationary phases (Sil-Im-C18) were prepared by adjusting introduction interval of octadecyltrichlorosilane (ODS) and 3-imidazol-1-ylpropyl(trimethoxy)silane (TMPImS), which can be used for reversed-phase liquid chromatography (RPLC) and ion exchange chromatography (IEC) with adjustable performance. The successful preparation of Sil-Im-C18 were confirmed by the characterizations of elemental analysis, infrared spectroscopy (FTIR) and contact angle (CA). Chromatographic performance of Sil-Im-C18 were evaluated by the separation of Tanaka test mixture, alkylbenzenes, linear PAHs and a set of analytes with different properties (uracil, phenol, 1,2-dinitrobenzene and naphthalene), and compared with commonly used C18 column. It was found that the chromatographic performance of Sil-Im-C18 changed significantly with the difference in bonding amount of imidazole and C18. Sil-Im-C18 demonstrated the excellent separation performance towards polycyclic aromatic hydrocarbons (PAHs), phenylesters, phenylamines, phenols and inorganic anions, and notably, nucleobases and nucleosides can be separated using pure water as mobile phases. The van Deemter plot showed that the column efficiency of Sil-Im-C18-3 was 64,933 plate·m-1 for naphthalene, indicated that Sil-Im-C18 was reasonably chromatographic columns. The RSD values of retention time were 0.22 %-0.61 % for 10 needles alkylbenzenes injected continuously at 50 °C to investigate thermal stability and repeatability, all the fluctuations of k of naphthalene were less than 2.3 % for Sil-Im-C18-1 during flushing 24 h with the mobile phase at different pH values (pH = 3 and 8), the retention time of alkylbenzenes were almost same for Sil-Im-C18-1 at different time, the RSD values of retention time of alkylbenzenes were 0.45 %-2.28 % for two batches Sil-Im-C18-1, revealing the excellent repeatability, thermal stability, durability and reproducibility of Sil-Im-C18, and implying a commercial prospect.

13.
J Chromatogr A ; 1722: 464867, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38598895

RESUMO

Hydrogels with a unique three-dimensional network structure have been widely used in a variety of fields. However, hydrogels are prone to swelling under water-rich conditions, which severely limits their application in liquid chromatography. Therefore, producing a hydrogel with reliable performance and good mechanical property is essential. Smart temperature-sensitive chromatographic packings have attracted extensive attentions in recent years. In this work, sodium 4-styrenesulfonate and 1-octadecene were introduced into the poly(N-isopropylacrylamide) hydrogel to improve mechanical property and separation performance. As a consequence, a smart temperature-sensitive terpolymeric hydrogel modified silica stationary phase (ION-hydrogel@SiO2) was synthesized for multimode liquid chromatographic separation. It was found that this new ION-hydrogel@SiO2 column exhibited excellent chromatographic separation ability for a wide range of analytes. To a certain extent, this new column has a higher chromatographic separation efficiency compared to the commercial C18 column and XAmide column. Moreover, the use of low proportion of organic phase in chromatographic separation is conducive to the realization of green chromatography. By investigating the chromatographic separation mechanism, it has been demonstrated that the hydrogen bonding interaction is primarily responsible for the temperature-sensitive behavior of the hydrogel. Finally, the ION-hydrogel@SiO2 column was used for the determination of pyridoxine in the commercially available tablet samples. In conclusion, this study presents a feasible idea for the development of novel copolymer hydrogels as liquid chromatographic stationary phases.

14.
J Pharm Biomed Anal ; 244: 116128, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38598924

RESUMO

Genotoxic impurities (GTIs) are potential carcinogens that need to be controlled down to ppm or lower concentration levels in pharmaceuticals under strict regulations. The static headspace gas chromatography (HS-GC) coupled with electron capture detection (ECD) is an effective approach to monitor halogenated and nitroaromatic genotoxins. Deep eutectic solvents (DESs) possess tunable physico-chemical properties and low vapor pressure for HS-GC methods. In this study, zwitterionic and non-ionic DESs have been used for the first time to develop and validate a sensitive analytical method for the analysis of 24 genotoxins at sub-ppm concentrations. Compared to non-ionic diluents, zwitterionic DESs produced exceptional analytical performance and the betaine : 7 (1,4- butane diol) DES outperformed the betaine : 5 (1,4-butane diol) DES. Limits of detection (LOD) down to the 5-ppb concentration level were achieved in DESs. Wide linear ranges spanning over 5 orders of magnitude (0.005-100 µg g-1) were obtained for most analytes with exceptional sensitivities and high precision. The method accuracy and precision were validated using 3 commercially available drug substances and excellent recoveries were obtained. This study broadens the applicability of HS-GC in the determination of less volatile GTIs by establishing DESs as viable diluent substitutes for organic solvents in routine pharmaceutical analysis.

15.
Biomed Chromatogr ; : e5869, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38599336

RESUMO

The increasing demand for honey purification and authentication necessitates the global utilization of advanced processing tools. Common honey processing techniques, such as chromatography, are commonly used to assess the quality and quantity of valuable honey. In this study, 15 honey samples were authenticated using HPLC and GC-MS chromatographic methods to analyze their pollen spectrum. Various monofloral honey samples were collected, including Acacia, Hypoestes, Lavandula, Tamarix, Trifolium, and Ziziphus species, based on accurate identification by apiarists in 2023 from the Kingdom of Saudi Arabia. Honey analysis revealed the extraction of pollen from 20 different honeybee floral species. Pollen identified from honey samples using advanced chromatographic tools revealed dominant vegetation resources: Ziziphus species (23%), Acacia species (25%), Tamarix species (34%), Lavandula species (26%), Hypoestes species (34%), and Trifolium species (31%). This study uses HPLC to extract phenolic compounds, revealing dominant protocatechuic acid (4.71 mg g-1), and GC-MS to analyze organic compounds in honey pollen. Specifically, 2-dodecanone was detected with a retention time of 7.34 min. The utilization of chromatographic tools in assessing honey samples for pollen identification provides a reliable and efficient method for determining their botanical origins, thereby contributing to the quality control and authentication of honey products.

16.
Biomed Chromatogr ; : e5879, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38599673

RESUMO

This study aimed to investigate the dissipation pattern, risk assessment, and waiting period of myclobutanil on apple fruit (Malus domestica Borkh.) under temperate conditions in Kashmir, India. The study involved the application of myclobutanil 10 WP at a single recommended dosage (125 g a.i. ha-1) and double dosage (250 g a.i. ha-1) on Red Velox apple trees, 2 months before harvest. GC equipped with an electron capture detector was used to analyze myclobutanil residues in fruit samples. The study revealed that myclobutanil, at both recommended and double recommended doses, dissipated rapidly and became nondetectable after 55 and 60 days, respectively. The waiting period for myclobutanil application was determined to be 12.41 days for the single dose and 25.58 days for the double dose, respectively. These waiting periods were based on the maximum residue limit of 0.6 ppm as prescribed by the Codex Alimentarius Commission, Food Safety and Standards Authority of India, and European Commission. The study concludes that myclobutanil 10 WP is safe for consumers at both recommended and double recommended doses when applied 2 months before harvest. Risk assessment, considering the average daily apple consumption in India and theoretical maximum residue contributions (TMRCs), indicates negligible health hazards even at double the recommended dosage. The calculated TMRC values at Day 0 were significantly below the maximum permissible intake. For average and maximum myclobutanil residues at single and double doses, the TMRC values were found to be 0.0069 and 0.0070 mg day-1 person-1 and 0.0105 and 0.0106 mg day-1 person-1, respectively. These results indicate that myclobutanil, when used according to recommended dosages and waiting periods, poses minimal health risks to consumers. The study emphasizes the importance of prudent fungicide use to minimize fungicide residues on fruits, thereby ensuring their safety for consumption.

17.
J Chem Ecol ; 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38600408

RESUMO

Spraying urine on vertical objects by raising the tail is a commonly observed functional behavior for chemical communication in Felidae species, including domestic cats (Felis silvestris catus). The sprayed urine is recognized as a chemical signal for territorial ownership of their habitats. Previous studies reported that sprayed urine emits a more pungent odor than urine excreted from a squatting position. However, little is known about how sprayed urine acts as a strong scent mark in the environment. Here, we showed that sprayed urine originates only from bladder urine without any secretions, such as anal sac secretions, but it can effectively emit volatile organic compounds (VOCs) when smeared on vertical objects due to its strong adhesion. Chemical profiles of VOCs and odor qualities were similar between fresh sprayed urine and bladder urine sampled immediately after spraying from the same individuals. Meanwhile, feline-specific proteinuria arising from excretion of a carboxylesterase that produces a precursor of cat-specific odorants resulted in reduced surface tension of the urine and increased adhesion to vertical surfaces, which kept sprayed urine on the surfaces and led to the emission of large amounts of VOCs. In conclusion, proteinuria contributes to the emission of a strong odor through its enhanced adhesion to vertical objects without other secretions containing malodorous substances. These findings improve our understanding of the mechanism of scent marking via the spraying of urine for chemical communication in cats.

18.
Biomed Chromatogr ; : e5876, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38600635

RESUMO

The two-step preconcentration technique consisting of large-volume sample stacking (LVSS) and micelle to solvent stacking (MSS) in cyclodextrin-modified electrokinetic chromatography (CDEKC) was developed for the analysis of five cationic alkaloids in complex Chinese herbal prescriptions. Relevant parameters affecting separation and stacking performance were optimized separately. Under the optimal LVSS-MSS-CDEKC conditions, less analysis time and organic solvent were required, and the enhancement factors of analytes ranged from 12 to 15 compared with the normal CDEKC separation mode. Further, all validation results demonstrated good applicability and multiple alkaloids (epiberberine, dehydrocorydaline, jatrorrhizine, coptisine and berberine) in Yangxinshi tablet (YXST) have been simultaneously determined. This approach presents powerful potential for the determination of multiple components in complex preparations of Chinese medicine.

19.
Drug Test Anal ; 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38600723

RESUMO

Methadone has two enantiomers, which exhibit differences in pharmacological effects, with R-methadone being the active and S-methadone the inactive enantiomer. A robust, simple and rapid method for chiral separation of the two enantiomers in serum samples using ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MSMS) has been developed and validated. Enantiomeric separation was achieved using a Chiralpak IH-3 column with a mobile phase consisting of CO2 and 30mM ammonium acetate in methanol/water (98/2, v/v). Runtime was 4 minutes. Sample preparation was semi-automated using a Hamilton ML Star robot with protein precipitation, and phospholipid removal was carried out using a Waters OSTRO™ 96-well plate. The calibration range was 50.0-1,500 nM for each enantiomer. The between-assay relative standard deviations were in the range of 1.2-3.6%. Matrix effects ranged from 99% to 115% corrected with internal standard. The method has been implemented in our laboratory and has proven to be a robust and reliable method for determining the ratio of R/S-methadone in authentic patient samples.

20.
Prep Biochem Biotechnol ; : 1-11, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38592940

RESUMO

We established an efficient method using high-speed countercurrent chromatography (HSCCC) combined with preparative high-performance liquid chromatography (prep-HPLC) for isolating and purifying Gelsemium elegans (G. elegans) alkaloids. First, the two-phase solvent system composed of 1% triethylamine aqueous solution/n-hexane/ethyl acetate/ethanol (volume ratio 4:2:3:2) was employed to separate the crude extract (350 mg) using HSCCC. Subsequently, the mixture that resulted from HSCCC was further separated by Prep-HPLC, resulting in seven pure compounds including: 14-hydroxygelsenicine (1, 12.1 mg), sempervirine (2, 20.8 mg), 19-(R)-hydroxydihydrogelelsevirine (3, 10.1 mg), koumine (4, 50.5 mg), gelsemine (5, 32.2 mg), gelselvirine (6, 50.5 mg), and 11-hydroxyhumanmantenine (7, 12.5 mg). The purity of these seven compounds were 97.4, 98.9, 98.5, 99, 99.5, 96.8, and 85.5%, as determined by HPLC. The chemical structures of the seven compounds were analyzed and confirmed by electrospray ionization mass spectrometry (ESI-MS), 1H-nuclear magnetic resonance (1H NMR), and 13 C-nuclear magnetic resonance (13 C NMR) spectra. The results indicate that the HSCCC-prep-HPLC method can effectively separate the major alkaloids from the purified G. elegans, holding promising prospects for potential applications in the separation and identification of other traditional Chinese medicines.

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