Advances in enantiomeric resolution on monolithic chiral stationary phases in liquid chromatography and electrochromatography

Chirality identification of Ibuprofen enantiomers by a terahertz polarization-sensitive metasurface sensor

Chirality plays an important role in medicine, biology, and chemistry. Molecules of different chirality could display dramatically different medical effects, pharmacological activities, and physiological impacts. Ibuprofen is an important anti-inflammatory drug in clinics. The anti-inflammatory effect is almost solely attributed to the (S)-(+)-Ibuprofen, while its enantiomer (R)-(-)-Ibuprofen plays a negative effect on increasing the metabolic burden. In this work, a terahertz (THz) polarization-sensitive metasurface sensor is proposed for qualitative and quantitative identification of the chiral Ibuprofen. The chirality parameters of Ibuprofen are extracted from the circular-polarized transmission coefficients. The parameters are further used to simulate the coupling mechanism between the Ibuprofen and the sensor to explain the principle of recognition. The sensitivities of (R)-(-)-Ibuprofen and (S)-(+)-Ibuprofen are found to be 1.5 THz/(mg/L) and 1.8 THz/(mg/L) for the TM polarization, respectively, and 1.7 THz/(mg/L) and 2.1 THz/(mg/L) for the TE polarization, respectively. The difference enables the chirality identification according to the different frequency shift at the same concentration. The exceptional specificity and sensitivity provide a new avenue for chiral molecular recognition.

UPLC-ESI-Q-TOF-MS/MS based metabolomics investigation on chemical constituent consistency of Zhenwu Decoction before and after compatibility

Zhenwu Decoction (ZWD), a classic formula from Zhang Zhongjing's "Treatise on Typhoid Fever" in the Han Dynasty, consists of five traditional Chinese medicines: Aconiti Lateralis Radix Praeparata (ALRP), Paeoniae Radix Alba, Poria Cocos, Ginger, and Rhizoma Atractylodis Macrocephalae. To evaluate the chemical constituent consistency of ZWD before and after compatibility, an ultra-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry was established to comprehensively study the constituents of ZWD. By normalizing the peak area, the pairwise compatibility of ALRP and the other four medicinal herbs, as well as the compatibility of the entire formula were studied, respectively. Multivariate statistical analysis was used to identify the differences. The processed data were analyzed by principal component analysis and supervised orthogonal partial least squared discriminant analysis, and an S-plot was generated to compare the differences in the chemical composition of the two types of decoction samples. The results showed that during the decoction process of ZWD, a total of seven components were recognized as differential compounds before and after compatibility of ZWD, namely 6-gingerol, zingerone, benzoylhypaconine, hypaconitine, benzoylaconine, paeoniflorin and fuziline. The results of this study provide basic data reference for understanding the law of ZWD compatibility and are valuable for the compatibility study of other herbal medicines.

Functionalized Chiral Materials for Use in Chiral Sensors

Chirality represents a fundamental attribute within living systems and is a pervasive phenomenon in the natural world. The identification and analysis of chiral materials within natural environments and biological systems hold paramount importance in clinical, chemical, and biological sciences. Within chiral analysis, there is a burgeoning focus on developing chiral sensors exhibiting exceptional selectivity, sensitivity, and stability, marking it as a forefront area of research. In the past decade (2013-2023), approximately 1990 papers concerning the application of various chiral materials in chiral sensors have been published. Biological materials and nanomaterials have important applications in the development of chiral sensors, which accounting for 26.67% and 45.24% of the material-related applications in these sensors, respectively; moreover, the development of chiral nanomaterials is closely related to the development of portable and stable chiral sensors. Natural chiral materials, utilized as selective recognition units, are combined with carriers characterized by good physical and chemical properties through functionalization to form various functional chiral materials, which improve the recognition efficiency of chiral sensors. In this article, from the perspective of biological materials, polymer materials, nanomaterials, and other functional chiral materials, the applications of chiral sensors are summarized and the research prospects of chiral sensors are discussed.

Development of dispersive solid phase extraction based on magnetic metal organic framework for the extraction of sunitinib in biological samples and its determination by high performance liquid chromatography-tandem mass spectrometry

Herein, a simple, sensitive, and reliable dispersive solid phase extraction was reported for the efficient extraction of sunitinib from biological samples. To facilitate the extraction of the desired analyte from urine and plasma samples, magnetic MIL-101Cr (NH2) @SiO2 @ NiFe2O4 was synthesized by a hydrothermal method and applied as an effective sorbent during the extraction process. After adsorption of the drug using 10 mg of MIL-101Cr (NH2) @ SiO2 @ NiFe2O4 nanoparticles through vortexing (1 min), the sorbent was separatedfrom the sample solution using a magnet. To eluate the drug, the sorbent containing the sunitinib was contacted with 100 µL dimethylformamide. The eluent was analyzed by high performance liquid chromatography-tandem mass spectrometry. Reasonable validation data consisting of low limits of detection (0.14, 0.35, and 0.70 ng mL-1 in deionized water, plasma, and urine) and quantification (0.48, 1.2, and 2.4 ng mL-1 in deionized water, plasma, and urine, respectively), a wide linear range of the calibration curve (0.48-200, 1.2-200, and 2.4-100 ng mL-1 in deionized water, plasma, and urine, respectively) good extraction recovery (76 %), and low relative standard deviations for inter- and intra-day precisions (6.9 %) were obtained by the method. Eventually, the proposed procedure was effectively implemented on both plasma and urine samples, yielding successful outcomes.

Preparation of magnetic amphiphilic resin microspheres via the one-step polymerization method and extraction of four glucocorticoids for HPLC-MS analysis

Amphiphilic materials can be used for sample preparation of chromatography or mass spectrometry. Amphiphilic materials with magnetic properties in combination with magnetic suction devices allow for automated sample preparation. However, conventional synthesis methods are cumbersome and not suitable for the mass production of the material. In this study, a micro-suspension polymerization method was developed to synthesize magnetic amphiphilic resin microspheres (MARMs), providing new ideas for the preparation of amphiphilic microspheres. MARMs with particle sizes ranging from 3 to 6 μm were successfully prepared, with BET surface area up to 653.2 m2/g. A magnetic solid-phase extraction method based on MARM-5 was developed for the extraction of four glucocorticoids including Cortisone, Hydrocortisone, Cortodoxone, and Corticosterone. This method had a very short adsorption time of 0.5 min and a total extraction time of only 13 min. The limit of detection for the four glucocorticoids ranged from 0.22 to 0.82 ng/L. There was a good linear relationship between sample concentration and peak area in the range of 25∼500 ng/L. Relative recovery of 98 %∼108 % and internal standard normalized matrix effect factors of 95∼114 % were obtained, and the relative standard deviation was between 2.3 % and 6.3 %. The MARMs would be used as excellent solid extraction material for glucocorticoids.

Application of three-dimensional material CZIF-8/CS-MS as adsorbents for the determination of plant growth regulators in Schisandra chinensis

In this study, we employed a melamine sponge (MS) as the skeleton material and utilized carbonized ZIF-8 (CZIF-8) and chitosan (CS) as the raw materials to prepare CZIF-8/CS-MS, a novel material featuring a three-dimensional interconnected porous network. The resulting CZIF-8/CS-MS material possesses a unique porous structure, significant specific surface area and abundant active sites. These characteristics make CZIF-8/CS-MS a promising absorbent for selective purification of plant growth regulators (PGRs) including 1-naphthlcetic acid (NAA), naphthoxyacetic acid (NOA), 4-chlorophenoxyacetic acid (4-CPA), 2,4-dichlorophenoxyacetic acid (2,4-D). After optimizing the extraction conditions, excellent linearity (r > 0.9994) was observed within a wide linear range of 1-100 ng/mL using ultra high performance liquid chromatography-tandem quadrupole mass spectrometry. The detection limits (LODs) and limits of quantification (LOQs) were found to be in the range of 0.013-0.154 ng/mL and 0.044-0.515 ng/mL, respectively. Additionally, the relative recovery of Schisandra chinensis fruit samples was determined to be 89.7-99.4 %, with a relative standard deviation (RSDs) of ≤ 8.4 % (n = 3). Compared to other methods, this approach offers a multitude of benefits, which include but are not limited to exceptional sensitivity, reduced sample volume requirements, low LODs, a comparable linear range, and high reproducibility. The findings of this study pave the way for exploring novel functionalized sponge columns, which leverage the integration of nano-sorbent materials and coating agents, for the purpose of analyzing PGRs within intricate matrix samples.

Molecular recognition and binding between human plasminogen Kringle 5 and α-chain of human complement component C3b by frontal chromatography and dynamics simulation

The binding and molecular recognition between α-chain of human complement C3b (α-chain of C3b) and human plasminogen Kringle 5 (Kringle 5) were studied and explored by frontal chromatography and dynamics simulation in the combination of bio-specific technologies. The specific interaction between the α-chain of C3b and Kringle 5 was initially confirmed by ligand blot and ELISA (Kd = 4.243×10-6 L/mol). Furthermore, the binding determination conducted via frontal chromatography showed that the presence of a single binding site between them, with the binding constant of 2.98 × 105 L/mol. Then the molecular recognition by dynamics simulation and molecular docking showed that there were 9 and 13 amino acid residues respective in the Kringle 5 and α-chain of C3b directly implicated in the binding and the main stabilizing forces were electrostatic force (-55.99 ± 11.82 kcal/mol) and Van der Waals forces (-42.70 ± 3.45 kcal/mol). Additionally, a loop structure (65-71) in Kringle 5 underwent a conformational change from a random structure to an α-helix and a loop structure (417-425) in α-chain of C3b was closer to the molecular center, both of them were more conducive to the binding between them. Meanwhile, the involvement of the lysine binding site of Kringle 5 played an important role in the binding process. In addition, the erythrocyte-antibody complement rosette assay substantiated that the presence of Kringle 5 hindered the transportation of α-chain of C3b to antigen-antibody complex in a dose-dependent manner. These findings collectively indicated that the α-chain of C3b is very likely a receptor protein for Kringle 5, which provides a methodology for other similar investigations and valuable insights into expansion of the pharmacological effects and potential application of Kringle 5 in immune-related diseases.

Enantiomeric separation of thiourea derivatives of naringenin on amylose and cellulose polymeric chromatographic chiral columns

Due to a great demand for amylose and cellulose polymeric chromatographic chiral columns, the enantiomeric separation of thiourea derivatives of naringenin was achieved on the different amylose (Chiralpak-IB) and cellulose chiral (Chiralcel-OJ and Chiralcel-OD-3R) columns with varied chromatographic conditions. The isocratic mobile phases used were ethanol and methanol, where ethanol/hexane and methanol/hexane were used as gradient mode and were prepared in volume/volume relation. The separation and resolution factors for all the enantiomers were in the range of 1.25 to 3.47 and 0.48 to 1.75, respectively. The enantiomeric resolution was obtained within 12 min making fast separation. The docking studies confirmed the chiral recognition mechanisms with binding affinities in the range of -4.7 to -5.7 kcal/mol. The reported compounds have good anticoagulant activities and may be used as anticoagulants in the future. Besides, chiral separation is fast and is useful for enantiomeric separation in any laboratory in the world.

Simultaneous identification and enantioseparation of ofloxacin and duloxetine without the single standard and computational calculation of their inclusion complexes

Given the markedly different pharmacological activities between enantiomeric isomers, it is crucial to encourage the stereoselective determination of chiral drugs in the biological and pharmaceutical fields, and the combination of drugs makes this analysis more complicated and challenging. Herein, a capillary electrophoresis (CE) method for the enantioseparation of ofloxacin and duloxetine was established, enabling the simultaneous identification of four isomers in nonracemic mixtures with enantiomeric excess (ee%) values exceeding 5%. This was achieved through the integration of theoretical simulation and electron circular dichroism (ECD), all without reliance on individual standards. Molecular modeling explained and verified the migration time differences of these isomers in electrophoretic separation. Moreover, the correlation coefficients (R2 ) between the enantiomeric peak area differentials and ee% were both above 0.99. Recovery rates were quantified using bovine serum as the matrix, with results ranging from 93.32% to 101.03% (RSD = 0.030) and 92.69% to 100.52% (RSD = 0.028) for these two chiral drugs at an ee value of 23.1%, respectively.

Dispersive solid phase extraction of tacrolimus from biological samples using curcumin and iron-based metal organic frameworks nanocomposite followed by LC-MS/MS determination

Tacrolimus is a potent immunosuppressive drug used in the prevention of tissue rejection. It has a narrow therapeutic index. Therefore, the determination of its concentration in biological fluids like plasma and urine is a very crucial issue. In this research, tacrolimus concentrations in plasma and urine samples were determined with a dispersive solid phase extraction procedure coupled to high-performance liquid chromatography-tandem mass spectrometry. For this purpose, a curcumin modified metal-organic framework was synthesized and used in extraction procedure. Tacrolimus was adsorbed onto the sorbent surface with aid of vortexing. Then, the adsorbed tacrolimus was eluted by a suitable solvent. Important parameters in extraction procedure were optimized by "one-variable-at-a-time" approach and reported as below: sorbent amount, 10 mg; sample solution pH, 2; agitation mode, vortexing; adsorption and desorption times, 1 min, and eluent (volume), methanol (200 µL). Under the optimized conditions and according to the International Council for Harmonization guidelines, the validation of the method was performed, and the results showed acceptable accuracy and precision (relative standard deviations ≤14 %), good linearity in a wide range (4-200 ng mL-1), and low limits of detection (1.2 ng mL-1 in plasma and 0.34 ng mL-1 in urine) and quantification (4.7 ng mL-1 in plasma and 1.12 ng mL-1 in urine). Finally, the validated method was successfully applied for the determination of tacrolimus in the plasma samples of the patients.

Preparation of chiral monoliths with new modulation of the monolith surface chemistry for the enantioseparation of chiral drugs by nano-liquid chromatography

Here, we report the preparation and application of two new chiral monoliths for the enantioseparation of chiral drugs in nano-LC. Using 3‑chloro-2-hydroxypropylmethacrylate (HPMA-Cl, 2) as a precursor monomer, two different chiral monomers namely, Nα-Boc-Lys-HPMA (3A) and Nα-Fmoc-Lys-HPMA (3B) were synthesized and used for the preparation of chiral polymer monoliths. The first monolithic column (referred to as monolith I) was prepared by an in-situ polymerization of Nα-Boc-Lys-HPMA as the chiral monomer and ethylene dimethacrylate while the second monolithic column (referred to as monolith II) was prepared by an in-situ polymerization of Nα-Fmoc-Lys-HPMA as the chiral monomer and ethylene dimethacrylate as the crosslinker. Methanol and 1-propanol were used as the porogenic solvents. The prepared chiral monoliths were investigated for the enantioseparation of chiral drugs, including β-blockers (e.g., atenolol, propranolol, metoprolol) and anti-inflammatory drugs (e.g., ketoprofen, ibuprofen, flurbiprofen, naproxen, etodolac). The enantioseparation could be achieved via the formation of π-π interactions on the aromate-rich and aromate-poor chiral molecules while enantioseparation mechanism of chiral drugs included mostly π-π interactions and hydrogen bonding. Monolith II showed better enantioselectivity than Monolith I and the resolution values up to 2.12 were successfully achieved.

Chiral resolution of (±)-flurbiprofen using molecularly imprinted hydrazidine-modified cellulose microparticles

Flurbiprofen (FP) is one of the non-steroidal anti-inflammatory drugs (NSAIDs) commonly used to treat arthritic conditions. FP has two enantiomers: S-FP and R-FP. S-FP has potent anti-inflammatory effects, while R-FP has nearly no such effects. Herein, molecularly imprinted microparticles produced from hydrazidine-cellulose (CHD) biopolymer for the preferential uptake of S-FP and chiral resolution of (±)-FP were developed. First, cyanoethylcellulose (CECN) was synthesized, and the -CN units were transformed into hydrazidine groups. The developed CHD was subsequently shaped into microparticles and ionically interacted with the S-FP enantiomer. The particles were then imprinted after being cross-linked with glutaraldehyde, and then the S-FP was removed to provide the S-FP enantio-selective sorbent (S-FPCHD). After characterization, the optimal removal settings for the S- and R-FP enantiomers were determined. The results indicated a capacity of 125 mg/g under the optimum pH range of 5-7. Also, S-FPCHD displayed a noticeable affinity toward S-FP with a 12-fold increase compared to the R-FP enantiomer. The chiral resolution of the (±)-FP was successfully attempted using separation columns, and the outlet sample of the loading solution displayed an enantiomeric excess (ee) of 93 % related to the R-FP, while the eluent solution displayed an ee value of 95 % related to the S-FP.

Identifying phenolics by UPLC-MS/MS in some Prangos Lindl. species and α-glucosidase inhibitory activities

Diabetes mellitus is a chronic metabolic disorder associated with biochemical, physiological, and pathological changes in the liver and characterized by some deficiencies in insulin secretion or insulin action. Prangos Lindl. species are important plants used as spice and medicine in Asian countries, including Türkiye. This study first aimed to evaluate the antidiabetic potential of the aerial parts of the 5 different Prangos species (Apiaceae) collected from various locations to discover and identify bioactive phenolic components. The results revealed that the methanolic extract of P. heyniae exhibited the highest activity against α-glucosidase inhibition compared to the other Prangos species (IC50 = 458.54 ± 5.62 μg/mL). For this reason, the active species P. heyniae (an endemic species) was subjected to UPLC-MS/MS to evaluate the possible active phenolic components. The results showed that 53 phenolic compounds were correctly screened, 21 were precisely determined by UPLC-MS/MS in P. heyniae. Therefore, it was concluded that the aerial parts of P. heyniae might have therapeutic potential for hyperglycemia due to its phenolic compounds. Moreover, quinic acid (3.66%), chlorogenic acid (2.35%), rutin (2.96%), and hesperidin (0.79%) might be potential markers of the methanolic extract of P. heyniae. In the end, this study provides comprehensive knowledge regarding the phenolic profile of P. heyniae related to antidiabetic activity for the first time in this study.

Flavor Quality Analysis of Ten Actinidia arguta Fruits Based on High-Performance Liquid Chromatography and Headspace Gas Chromatography-Ion Mobility Spectrometry

Actinidia arguta is a fruit crop with high nutritional and economic value. However, its flavor quality depends on various factors, such as variety, environment, and post-harvest handling. We analyzed the composition of total soluble sugars, titratable acids, organic acids, and flavor substances in the fruits of ten A. arguta varieties. The total soluble sugar content ranged from 4.22 g/L to 12.99 g/L, the titratable acid content ranged from 52.55 g/L to 89.9 g/L, and the sugar-acid ratio ranged from 5.39 to 14.17 at the soft ripe stage. High-performance liquid chromatography (HPLC) showed that citric, quinic, and malic acids were the main organic acids in the A. arguta fruits. Headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) detected 81 volatile compounds in 10 A. arguta varieties, including 24 esters, 17 alcohols, 23 aldehydes, 7 ketones, 5 terpenes, 2 acids, 1 Pyrazine, 1 furan, and 1 benzene. Esters and aldehydes had the highest relative content of total volatile compounds. An orthogonal partial least squares discriminant analysis (OPLS-DA) based on the odor activity value (OAV) revealed that myrcene, benzaldehyde, methyl isobutyrate, α-phellandrene, 3-methyl butanal, valeraldehyde, ethyl butyrate, acetoin, (E)-2-octenal, hexyl propanoate, terpinolene, 1-penten-3-one, and methyl butyrate were the main contributors to the differences in the aroma profiles of the fruits of different A. arguta varieties. Ten A. arguta varieties have different flavors. This study can clarify the differences between varieties and provide a reference for the evaluation of A. arguta fruit flavor, variety improvement and new variety selection.

Nano solid phase micro membrane tip and electrochemical methods for vanillin analysis in chocolate samples

A polymer-based nanosensor and electrochemical methods were developed for the quantitative analysis of vanillin. The sample preparation was done using nano solid phase micro membrane tip extraction (NSPMMTE). A novel poly(phenylalanine)/TiO2/CPE sensor was built as the working electrode for the first time for the analysis of the vanillin substance. The electrochemical behavior and analytical performance of vanillin were examined in detail by cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV) techniques via the oxidation process. The optimized modules of the DPSV technique that affected the vanillin peak current and peak potential were pH, pulse amplitude, step potential, and deposition time. The electroactive surface areas of bare CPE, TiO2/CPE, and poly(phenylalanine)/TiO2/CPE electrodes were found to be 0.135 cm2, 0.155 cm2, and 0.221 cm2, respectively. The limit of detection (LOD) was 32.6 μg/L in the 0.25-15.0 mg/L working range at pH 7.0. The selectivity of the proposed DPSV method for the determination of vanillin on the modified electrode was investigated in the presence of various organic and inorganic substances, and the determination of vanillin with high recovery was achieved with less than 5% relative error. The analytical application was applied in chocolate samples and the DPSV method was found highly efficient, reproducible, and selective.

Ultra-high-performance liquid chromatography-tandem high-resolution elevated mass spectrometry profiling of anti-methicillin-resistant Staphylococcus aureus metabolites from the endophytic bacteria collected from the weeds of a previous dumpsite

The culturable endophytic bacteria from the weeds Cleome rutidosperma of the family Cleomaceae and Digitaria sanguinalis of the family Poaceae obtained from a previous dumpsite in Pampanga, Philippines have been assessed for their anti-methicillin-resistant Staphylococcus aureus (MRSA) activity, and the analytes with such activity should be identified. However, due to the limited amounts collected from the isolation process, 1.8 mg yield of compound 1 from the endophyte of C. rutidosperma and 1.2 mg of a mixture from the endophyte of D. sanguinalis were selected for LC-MSE analysis. The production of compounds from the culturable endophytic bacteria Pseudomonas aeruginosa- determined by gene-sequencing, an untargeted and data-independent analysis (DIA) by ultra-high performance liquid chromatography-high resolution-elevated energy mass spectrometry (UHPLC-HR-MSE) technique was employed to profile the metabolites present in the two high-performance liquid chromatography (HPLC) fractions. The analytes present from P. aeruginosa detected by UHPLC-HR-MSE isolated from C. rutidosperma was phenazine-1-carboxylic acid (1), and for D. sanguinalis were chamigrenal (2), dialkyl resorcinol (3), and a pyoverdine elicitor (4). This study proves that UHPLC-HR-MSE could identify the anti-MRSA constituents in P. aeruginosa from commensal weeds C. rutidosperma and D. sanguinalis. The UHPLC-HR-MSE could help strengthen metabolomics antibacterial research and its related applications from a future perspective. Application of metabolomics research using UHPLC-HR-MSE could enhance the rehabilitation of dumpsites by the microbial community present.

Comprehensive Evaluation of Ten Actinidia arguta Wines Based on Color, Organic Acids, Volatile Compounds, and Quantitative Descriptive Analysis

Actinidia arguta wine is a low-alcoholic beverage brewed from A. arguta with a unique flavor and sweet taste. In this study, the basic physicochemical indicators, color, organic acid, and volatile aroma components of wines made from the A. arguta varieties 'Kuilv', 'Fenglv', 'Jialv', 'Wanlv', 'Xinlv', 'Pinglv', 'Lvbao', 'Cuiyu', 'Tianxinbao', and 'Longcheng No.2' were determined, and a sensory evaluation was performed. The findings show that 'Tianxinbao' produced the driest extract (49.59 g/L), 'Kuilv' produced the most Vitamin C (913.46 mg/L) and total phenols (816.10 mg/L), 'Jialv' produced the most total flavonoids (477.12 mg/L), and 'Cuiyu' produced the most tannins (4.63 g/L). We analyzed the color of the A. arguta wines based on CIEL*a*b* parameters and found that the 'Kuilv' and 'Longcheng No.2' wines had the largest L* value (31.65), the 'Pinglv' wines had the greatest a* value (2.88), and the 'Kuilv' wines had the largest b* value (5.08) and C*ab value (5.66) of the ten samples. A total of eight organic acids were tested in ten samples via high-performance liquid chromatography (HPLC), and we found that there were marked differences in the organic acid contents in different samples (p < 0.05). The main organic acids were citric acid, quinic acid, and malic acid. The aroma description of a wine is one of the keys to its quality. A total of 51 volatile compounds were identified and characterized in ten samples with headspace gas chromatography-ion mobility spectrometry, including 24 esters, 12 alcohols, 9 aldehydes, 3 aldehydes, 2 terpenes, and 1 acid, with the highest total volatile compound content in 'Fenglv'. There were no significant differences in the types of volatile compounds, but there were significant differences in the contents (p < 0.05). An orthogonal partial least squares discriminant analysis (OPLS-DA) based on the odor activity value (OAV) showed that ethyl butanoate, ethyl pentanoate, ethyl crotonate, ethyl isobutyrate, butyl butanoate, 2-methylbutanal, ethyl isovalerate, and ethyl hexanoate were the main odorant markers responsible for flavor differences between all the A. arguta wines. Sensory evaluation is the most subjective and effective way for consumers to judge A. arguta wine quality. A quantitative descriptive analysis (QDA) of the aroma profiles of ten grapes revealed that the 'fruity' and 'floral' descriptors are the main and most essential parts of the overall flavor of A. arguta wines. 'Tianxinbao' had the highest total aroma score. The flavor and quality of A. arguta wines greatly depend on the type and quality of the A. arguta raw material. Therefore, high-quality raw materials can improve the quality of A. arguta wines. The results of the study provide a theoretical basis for improving the quality of A. arguta wines and demonstrate the application prospects of HS-GC-IMS in detecting A. arguta wine flavors.

Advances in Simple and Chiral-HPLC Methods for Antiallergic Drugs and Chiral Recognition Mechanism

Among many diseases, allergy appears to be a serious problem for human beings. Various forms of allergic disorders make people tense, leading to some other health issues. Many medications, including nonracemic and racemic ones, are used to treat this problem. It is important to have exact analysis strategies just to see any medication side effects, plasma profiles, and working efficiency. Therefore, efforts are made to review simple and chiral HPLC methods for antiallergic drugs; HPLC is the best analytical technique. The highlights in this article include the world scenario, causes of allergy, the effect of allergy on the economy, the mechanism of allergy in humans, classes of antiallergic drugs, simple drugs, chiral drugs, analysis by HPLC, and the chiral recognition mechanism. Moreover, attempts are also made to highlight the management of allergies and future perspectives.

Fast and Simple Liquid Chromatography-Isotope Dilution Tandem Mass Spectrometry Method for Therapeutic Drug Monitoring of Dalbavancin in Long-Term Treatment of Subacute and/or Chronic Infections

Dalbavancin (DBV) is a long-acting antistaphylococcal lypoglycopeptide that is being increasingly used for long-term treatment of a wide range of subacute and/or chronic infections, mainly osteo-articular infections (OAI). Population pharmacokinetic studies showed that two 1500 mg doses 1 week apart can ensure effective treatment for several weeks. In this scenario, therapeutic drug monitoring (TDM) can be a helpful tool for providing clinicians with real-time feedback on the duration of optimal treatment by measuring drug concentrations over time in each single patient. The aim of this study was to develop and validate a fast and simple analytical method based on the Liquid Chromatography-Isotope Dilution Tandem Mass Spectrometry (ITD LC-MS/MS) technique for measuring DBV concentrations in human plasma microsamples. It will allow an innovative, very convenient and minimally invasive way of sampling. Analysis was performed by simple single-step sample preparation and very short instrumental run time (4 min). Analytical performance met all criteria in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, dilution integrity and stability under different conditions set by the European Medicines Agency (EMA) for drug quantification by means of bioanalytical methods. The method was successfully applied for measuring DBV concentrations (range = 2.0-77.0 mg/L) in a cohort of patients receiving long-term DBV treatment of subacute and/or chronic infections.

Fundamentals of chirality, resolution, and enantiopure molecule synthesis methods

The chirality of molecules is a concept that explains the interactions in nature. We may observe the same formula but different organizations revolving around the chiral center. Since Pasteur's meticulous observation of sodium ammonium tartrate crystals' structure, scientists have discovered many features of chiral molecules. The number of newly approved single enantiomeric drugs increases every year and takes place in the market. Thus, separation or resolution methods of racemic mixtures are of continued importance in the efficacy of drugs, installation of affordable production processes, and convenient synthetic chemistry practice. This article presents the asymmetric synthesis approaches and the classification of direct resolution methods of chiral molecules.

Application of Box-Behnken experimental design and response surface methodology for selecting the optimum RP-HPLC conditions for the simultaneous determination of methocarbamol, indomethacin and betamethasone in their pharmaceutical dosage form

An isocratic RP-HPLC method has been developed for the separation and determination of methocarbamol (MTL), indomethacin (IND), and betamethasone (BET) in combined dosage form using an Inertsil ODS-3v C18 (250 × 4.6 mm, 5 μm) column with UV- detection at 235 nm. Experimental design using Box-Behnken design (BBD) was applied to study the response surface during method optimization and to achieve a good separation with a minimum number of experimental runs. The three independent parameters were pH of buffer, % of acetonitrile and flow rate of the mobile phase while the peak resolution of IND from MTL and the peak resolution of BET from IND (R2) were taken as responses to obtain mathematical models. The composite desirability was employed to optimize a set of responses overall (peak resolutions). The predicted optimum assay conditions include a mobile phase composition of acetonitrile and phosphate buffer (pH 5.95) in a ratio of 79:21, v/v, pumped at a flow rate of 1.4 mL min^-1. With this ideal condition, the optimized method was able to achieve baseline separation of the three drugs with good resolution and a total run time of less than 7 min. The linearity of MTL, IND, and BET was determined in the concentration ranges of 5-600 µg mL^- 1, 5-300 µg mL^- 1, and 5-300 µg mL^- 1 and the regression coefficients were 0.9994, 0.9998, and 0.9998, respectively. The average percent recoveries for the accuracy were determined to be 100.41 ± 0.60%, 100.86 ± 0.86%, and 100.99 ± 0.65% for MTL, IND, and BET, respectively. The R.S.D.% of the intra-day precision was found to be less than 1%, while the R.S.D.% of the inter-day precision was found to be less than 2%. The RP-HPLC method was fully validated with regard to linearity, accuracy, precision, specificity, and robustness as per ICH recommendations. The proposed method has various applications in quality control and routine analysis of the investigated drugs in their pharmaceutical dosage forms and laboratory-prepared mixtures with the goal of reducing laboratory waste, analysis time, and effort.

Multidimensional Chromatography and Its Applications in Food Products, Biological Samples and Toxin Products: A Comprehensive Review

Food, drugs, dyes, extracts, and minerals are all made up of complex elements, and utilizing unidimensional chromatography to separate them is inefficient and insensitive. This has sparked the invention of several linked chromatography methods, each of them with distinct separation principles and affinity for the analyte of interest. Multidimensional chromatography consists of the combination of multiple chromatography techniques, with great benefits at the level of efficiency, peak capacity, precision, and accuracy of the analysis, while reducing the time required for the analysis. Various coupled chromatography techniques have recently emerged, including liquid chromatography–gas chromatography (LC–GC), gas chromatography–gas chromatography (GC–GC), liquid chromatography–liquid chromatography (LC–LC), GCMS–MS, LCMS–MS, supercritical fluid techniques with chromatography techniques, and electro-driven multidimensional separation techniques. In this paper, the different coupled chromatography techniques will be discussed, along with their wide spectrum of applications for food, flavor, and environmental analysis, as well as their usefulness for the pharmaceutical, color, and dyes industries.

Conversion of Enantiomers during the Separation of Acetoin from Fermentation Broth

Acetoin (AC) is an important platform compound with two enantiomers (R)-AC and (S)-AC. Due to its unique spatial structure, optically pure AC has particularly high application in asymmetric synthesis. Highly optically pure AC could be produced from glucose using biofermentation technology. In this paper, we have observed that the recovered AC product from the fermentation broth containing (R)-AC was a racemic mixture. The changes of the enantiomeric excess (e.e.) of (R)-AC enantiomers in the feed solution during the recovery process were then investigated, confirming that the racemization occurs during solvent distillation. Further studies showed that high temperature is the main factor affecting the conversion of the two enantiomers, while low temperature significantly prevents this conversion reaction. Therefore, we optimized the solvent recovery process and used vacuum distillation to reduce the distillation process temperature, which effectively prevented the racemization: obtains AC products with more than 98% purity and successfully maintained the proportion of (R)-AC above 96%. To our knowledge, this is the first report on the factors affecting the enantiomeric purity in the downstream extraction process of AC production by fermentation.

Rapid chiral separation of potential antibiotics using supercritical fluid chromatography

WHO is searching most active antibiotics due to the bacterial resistance problem. The activities of the racemic antibiotics may be augment by preparing optically active antibiotics by the chiral separation. Chiral separation of potential antibiotics such as cefotaxime and ofloxacin was studied using amylose-based packing chiral stationary phases (CSPs) such as Chiralpak IA and Chiralpak IG. Supercritical fluid chromatography (SFC) was employed to carry out this study. Both immobilized CSPs such as Chiralpak IA and IG have sown remarkable selectivity for the reported drugs by using SFC. The values of retention factor (k) for ofloxacin enantiomers were 9.63 and 11.81, followed by 2.94 and 5.96 for cefotaxime enantiomers. The values of separation factor (α) for both the reported drugs were 1.22 and 2.03, respectively Similarly, the values of resolution factor (Rs) for both the enantio-selective drugs were 1.49 and 2.06, separately and respectively. The chiral recognition mechanism was developed and it was observed that the π-π interactions are playing a major role. The developed method is effective, reproducible, eco-friendly, and may be used to discriminate the enantiomers of the reported drugs in any sample.

Box–Behnken Design-Based Development and Validation of a Reverse-Phase HPLC Analytical Method for the Estimation of Paclitaxel in Cationic Liposomes

Stability-indicating reverse-phase HPLC analytical method for the quantification of Paclitaxel (PTX) in the bulk and cationic liposomes was developed. The optimized method was validated according to the ICH Q2 (R1) guidelines by following a 2-level–4-factor interaction Box–Behnken design using Design-Expert® software. The responses measured at 228 nm were retention time (Rt), peak area, tailing factor (Tf10%), and the number of theoretical plates (NTP). PTX was eluted best using the Luna® C18 LC Column along with a mobile phase of methanol and 25 mM ammonium acetate buffer (pH 6) 75:25 v/v mixture at 25 ± 2 °C temperature. The currently developed method was linear in the 2.5–100 µg/mL range with a detection limit of 0.062 µg/mL and a quantification limit of 0.188 µg/mL. The optimized method was utilized to evaluate the stability of PTX in different stress conditions by performing forced degradation studies. The results from the degradation study stipulated that on exposure to various stressors, namely acid, alkali, oxidative, thermal, and UV light, the PTX did not show considerable degradation except alkali exposure. Further, the method was successfully used for the quantification of PTX in cationic liposomes. The particle size, zeta potential, and polydispersity index of the PTX-loaded liposomes were 219.25 ± 7.566 nm, 57.15 ± 12.374 mV, and 0.807 ± 0.1958 respectively. The percent of drug entrapped was quantified and was found to be 59 ± 1.414%.

Enantioseparation of basic drugs by reverse phase high-performance liquid chromatography system using carboxymethyl-β-cyclodextrin as chiral mobile phase additive

A rapid and efficient method was developed for enantioseparation of basic drugs, using carboxymethyl-β-cyclodextrin (CM-β-CD) as chiral mobile phase additive, rather than involving costly chiral column in high-performance liquid chromatography (HPLC) system. Four of the six basic drug enantiomers investigated were successfully separated. The highest resolution reaches 2.15 for threo-(1S,2S)-2-amino-l-p-nitrophenyl-1,3-propanediol. The effects of the organic modifier, pH value, concentration of chiral additive, column temperature, and flow rate of mobile phase on the enantioseparation of analytes were researched. The apparent formation constants of inclusion and the thermodynamic parameters were evaluated to explain the mechanism of chiral recognition.

Chiral separation of β-blockers by supercritical fluid chromatography using Chiralpak-IG and Chiralpak IBN-5 columns

Chiral separation of β-blockers is performed by utilizing the supercritical fluid chromatographic method. The chiral columns utilized were Chiralpak IG and Chiralpak IBN-5. The finest mobile phase was CO₂ -0.2% TEA in methanol (60:40). The values atenolol enantiomers retention factors were 6.39 and 8.98. These values for propranolol enantiomers were 3.39 and 4.06. These values for betaxolol enantiomers were 4.08 and 4.68. The separation and resolution factor values for atenolol, propranolol, and betaxolol were 1.41 and 3.33, 1.19 and 2.23, and 1.15 and 1.87, separately and respectively. By comparison, it was observed that Chiralpak IG column is better than Chiralpak IBN-5 column. Supercritical fluid chromatography has been found as the best analytical technique due to its high speed, being eco-friendly, and being economic. The various most probable interactions responsible for the chiral resolution are hydrogen bonding, dipole-dipole interactions, steric effect, and π-π interactions. The reported methods are effective, efficient, and reproducible and may be used to separate and identify atenolol, propranolol, and betaxolol in any unknown samples.

Chiral separation of calcium channel antagonists by SFC and HPLC using different immobilized chiral stationary phases

Supercritical fluid chromatography and high-performance liquid chromatography techniques are popular for the chiral separations of different drugs and pharmaceuticals. Therefore, this article describes a comparative study of the chiral separation of some calcium channel antagonists such as verapamil, gallopamil, and nisoldipine. The columns used were Chiralpak IG and Chiralpak ID (250 mm × 4.6 mm, 5.0 μm). The separation was achieved by using a variety of mobile phases in both techniques. The retention, separation, and resolution factors in SFC were in the range of 1.36-7.30, 1.09-1.72, and 1.16-3.47, while these values in the case of HPLC were 1.03-2.42, 1.12-1.35, and 0.49-2.46. The complete resolution of gallopamil and verapamil was achieved successfully. The chiral recognition was controlled by hydrogen bondings, π-π interactions, dipole induced dipole interactions, van der Waal forces, and steric effects. SFC was found to be a better technique than HPLC because of quick separation, good separation power, economic, environment-friendly, and green technology.

A comparative study of chiral separation of proton pump inhibitors by supercritical fluid chromatography and high-performance liquid chromatography

A comparative study of chiral separation of pantoprazole and rabeprazole is carried out using supercritical fluid chromatography and high-performance liquid chromatography. The columns used were Chiralpak IA and Chiralpak IE. The best mobile phase in supercritical fluid chromatography was carbon dioxide-0.2% triethylamine in methanol (60:40) and 0.1% triethylamine in n-hexane-ethanol (50:50) in high-performance liquid chromatography. For supercritical fluid chromatography, values of the retention factor of pantoprazole enantiomers were 3.97 and 4.88. These values for rabeprazole enantiomers were 6.10 and 7.52. The values of separation and resolution factor for pantoprazole and rabeprazole were 1.23 and 1.23 and 2.20 and 3.36, respectively. Similarly, for high-performance liquid chromatography, the values of retention factor for enantiomers of pantoprazole were 4.02 and 7.32. These values for rabeprazole enantiomers were 5.32 and 7.88, respectively. The values of separation and resolution factor for pantoprazole and rabeprazole were 1.82 and 1.48 and 9.22 and 6.58, respectively. A comparison was carried out, which confirmed supercritical fluid chromatography as the best method due to its fastness, eco-friendly, and inexpensiveness. The reported methods are effective, efficient, and reproducible and may be used to separate and identify pantoprazole and rabeprazole in any unknown samples.

A comparison of chiral resolution of antifungal agents on different polysaccharide chiral columns under various mobile phase modes: Application in the biological samples

The current article describes the chiral separation of tioconazole, miconazole, isoconazole, sertaconazole and terconazole, with Lux i-Cellulose 5 and Lux i-Amylose-1 chiral columns under organic polar, normal and reversed mobile phases modes. The mobile phase flow rate was 1 mL/min with 230 nm detection at 25 ± 1 °C temperature. The polar organic mobile phases offered certain advantages for separation such as short analysis time, order of elution, high plate numbers and favorable signal to noise ratio. The values of k, α and Rs were ranged from 0.6 to 7.87, 1.10 to 1.62 and 0.37 to 5.72 in polar organic, 0.15 to 43.86, 1.02 to 2.01 and 0.36 to 8.03 in normal, and 0.34 to 15.99, 1.03 to 1.40 and 0.59 to 4.18 in reversed phases modes, respectively. The reported methods were applied in urine samples and the results were satisfactory. The reported methods were applied to the analysis of urine samples.

Determination of Potential Genotoxic Impurity, 5-Amino-2-Chloropyridine, in Active Pharmaceutical Ingredient Using the HPLC-UV System

A novel analytical method, based on high-performance liquid chromatography with a UV (HPLC-UV) detection system for the sensitive detection of a genotoxic impurity (GTI) 5-amino-2-chloropyridine (5A2Cl) in a model active pharmaceutical ingredient (API) tenoxicam (TNX), has been developed and validated. The HPLC-UV method was used for the determination of GTI 5A2Cl in API TNX. The compounds were separated using a mobile phase composed of water (pH 3 adjusted with orthophosphoric acid): MeOH, (50:50: v/v) on a C18 column (150 × 4.6 mm i.d., 2.7 μm) at a flow rate of 0.7 mL min-1. Detection was carried out in the 254 nm wavelength. Column temperature was maintained at 40°C during the analyses and 10 μL volume was injected into the HPLC-UV system. The method was validated in the range of 1-40 μg mL-1. The obtained calibration curves for the GTI compound was found linear with equation, y = 40766x - 1125,6 (R2 = 0.999). The developed analytical method toward the target compounds was accurate, and the achieved limit of detection and limit of quantification values for the target compound 5A2Cl were 0.015 and 0.048 μg mL-1, respectively. The recovery values were calculated and found to be between 98.80 and 100.03%. The developed RP-HPLC-UV analytical method in this research is accurate, precise, rapid, simple and appropriate for the sensitive analysis of target GTI 5A2Cl in model API TNX.

Homochiral Metal-Organic Framework [Co(L)(bpe)2(H2O)2]·H2O Used for Separation of Racemates in High-Performance Liquid Chromatography

A homochiral metal-organic framework (MOF) comprising [Co(L)(bpe)2(H2O)2]·H2O was prepared using (1R,2R)-(-)-1,2-cyclohexanedicarboxylic acid (H2L) and 1,2-bis(4-pyridyl)-ethylene as organic ligands. The homochiral MOF [Co(L)(bpe)2(H2O)2]·H2O was explored as chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) separation of racemates. Nine racemates including naphthol, alcohol, diol, amine, ketone, ether and organic acid were well separated on the homochiral MOF [Co(L)(bpe)2(H2O)2]·H2O column (250 mm long × 4.6 mm i.d.). The relative standard deviation for five replicate separations of 1,1'-bi-2-naphthol is 0.69% for the retention time, indicating that the good reproducibility and stability of the homochiral MOF column for HPLC enantioseparation. The results indicated that the homochiral MOF as CSP is practical, which promotes the application of homochiral MOFs in HPLC.

Food safety and quality assessment: comprehensive review and recent trends in the applications of ion mobility spectrometry (IMS)

Ion mobility spectrometry (IMS) is an analytical separation and diagnostic technique that is simple and sensitive and a rapid response and low-priced technique for detecting trace levels of chemical compounds in different matrices. Chemical agents and environmental contaminants are successfully detected by IMS and have been recently considered to employ in food safety. In addition, IMS uses stand-alone or coupled analytical diagnostic tools with chromatographic and spectroscopic methods. Scientific publications show that IMS has been applied 21% in the pharmaceutical industry, 9% in environmental studies and 13% in quality control and food safety. Nevertheless, applications of IMS in food safety and quality analysis have not been adequately explored. This review presents the IMS-related analysis and focuses on the application of IMS in food safety and quality. This review presents the important topics including detection of traces of chemicals, rate of food spoilage and freshness, food adulteration and authenticity as well as natural toxins, pesticides, herbicides, fungicides, veterinary, and growth promoter drug residues. Further, persistent organic pollutants (POPs), acrylamide, polycyclic aromatic hydrocarbon (PAH), biogenic amines, nitrosamine, furfural, phenolic compounds, heavy metals, food packaging materials, melamine, and food additives were also examined for the first time. Therefore, it is logical to predict that the application of the IMS technique in food safety, food quality, and contaminant analysis will be impressively increased in the future. HighlightsCurrent status of IMS for residues and contaminant detection in food safety.To assess all the detected contaminants in food safety, for the first time.Identified IMS-related parameters and chemical compounds in food safety control.

Enantiomeric resolution of quinolones on crown ether CSP: Thermodynamics, chiral discrimination mechanism and application in biological samples

The enantiomers of quinolone racemates were resolved using chiral crown ether within 8 min. Thermodynamics data and modeling results were used to determine chiral recognition mechanism. The column used was (+)-Crownpack column (250 mm × 4.6 mm, 5 µm) with three mobile phases I: ACN:Water (80:20) + 10 mM H₂SO₄ and 10 mM CH₃COONH₄, II: ACN:Water (80:20) + 20 mM perchloric acid and III: EtOH:Water (80:20) + 20 mM perchloric acid. The flow rate of the mobile phases was 1.0 mL/min with UV detection at different wavelengths. The ranges of retention (k), separation (α), and resolution (Rs) factors were 1.00-5.40, 1.37-2.00 and 1.50-3.30. The tailing factor was 1.o for all peaks with 900-2325 as the number of theoretical plates were 8.0-10.0 and 32.4-22.1 µg. The difference in enthalpy, entropy and free energy varied in the range of -0.350 to -0.024, 18.74 × 10^-4 to 3.94 × 10^-4 and -0.918 to -0.143, respectively. The thermodynamic and docking results showed chiral discrimination due to physical forces of amnio group cations penetration into the chiral cavity of the chiral selector following hydrogen bindings. The binding energy of S-enantiomers was higher than R-enantiomers; confirming stronger binding of S-enantiomers with CSP than R-enantiomers. The described chiral-HPLC method was used for the analysis of the quinolone enantiomers in urine samples and the results were quite satisfactory. Therefore, the reported method may be used for the enantiomeric separation of quinolone enantiomers in urine samples.

Past, present, and future developments in enantioselective analysis using capillary electromigration techniques

Enantioseparation of chiral products has become increasingly important in a large diversity of academic and industrial applications. The separation of chiral compounds is inherently challenging and thus requires a suitable analytical technique that can achieve high resolution and sensitivity. In this context, CE has shown remarkable results so far. Chiral CE offers an orthogonal enantioselectivity and is typically considered less costly than chromatographic techniques, since only minute amounts of chiral selectors are needed. Several CE approaches have been developed for chiral analysis, including chiral EKC and chiral CEC. Enantioseparations by EKC benefit from the wide variety of possible pseudostationary phases that can be employed. Chiral CEC, on the other hand, combines chromatographic separation principles with the bulk fluid movement of CE, benefitting from reduced band broadening as compared to pressure-driven systems. Although UV detection is conventionally used for these approaches, MS can also be considered. CE-MS represents a promising alternative due to the increased sensitivity and selectivity, enabling the chiral analysis of complex samples. The potential contamination of the MS ion source in EKC-MS can be overcome using partial-filling and counter-migration techniques. However, chiral analysis using monolithic and open-tubular CEC-MS awaits additional method validation and a dedicated commercial interface. Further efforts in chiral CE are expected toward the improvement of existing techniques, the development of novel pseudostationary phases, and establishing the use of chiral ionic liquids, molecular imprinted polymers, and metal-organic frameworks. These developments will certainly foster the adoption of CE(-MS) as a well-established technique in routine chiral analysis.

Enantioselective LC-MS/MS method for the determination of cloperastine enantiomers in rat plasma and its pharmacokinetic application

Cloperastine is a central antitussive used to reduce the frequency and intensity of coughing on a short-term basis. In this study, a reliable chiral LC-MS/MS technology has been developed for the quantification of cloperastine enantiomers in the rat plasma. Carbinoxamine was selected as the internal standard. The enantioseparation of cloperastine was performed on a Chiralpak IA column with a mobile phase composed of acetonitrile-water-ammonium hydroxide (80:20:0.1, v/v/v) at a flow rate of 0.6 mL/min. Cloperastine enantiomers were detected by mass spectrometry in multiple reaction monitoring mode with a positive electrospray ionization source. The method was validated over the linear concentration range of 0.05 to 10.0 ng/mL (5.0 × 10^-4 ng to 0.10 ng) for both enantiomers. The lower limit of quantification (LLOQ) for each analyte was determined as 0.05 ng/mL. The relative standard deviations (RSDs) of intraday and interday precision was less than 13.9%, and the relative error (RE) of accuracy ranged from -5.4% to 6.1%, which were within the acceptance criteria. Finally, an application to the stereoselective pharmacokinetics of cloperastine in rats was successfully realized in our assay. The developed method on a commercially available Chiralpak IA column under isocratic mobile phase is advantageous to analyze cloperastine enantiomers in plasma samples collected for enantioselective metabolism or drug interaction studies.