Determination of hexachlorophene residue in fruits and vegetables by ultra-high performance liquid chromatography-tandem mass spectrometry.

A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) -LC-MS/MS method was developed for the determination of hexachlorophene in fruits and vegetables. Samples were extracted by acetonitrile and then salted with an acetate buffer system. Extractants neutral alumina (Al-N), strong cation exchange silica gel bonded adsorbent (SCX) and graphitized carbon black (GCB) were used for sample purification. The method demonstrates excellent accuracy and reproducibility. Under optimized conditions, the correlation coefficients of hexachlorophene were higher than 0.995 in the range of 0.5-20 ng/mL. The limit of quantification (LOQ) was 2.0 µg/kg. The average recoveries, assessed at three spiked levels (2.0, 4.0, and 20.0µg/kg) across various matrices including cabbage, celery, tomato, eggplant, potato, radish, cowpea, chives, apple, peach, grape, citrus, bitter melon, banana and hami melon ranged from 72.0 to 100.5% with relative standard deviations from 3.2 to 9.8% (n = 6).

Preparation and evaluation of a 1,1'-bi-2-naphthol-based chiral macrocycle bonded silica chiral stationary phase for high performance liquid chromatography.

Macrocycles play vital roles in supramolecular chemistry and chromatography. 1,1'-Bi-2-naphthol (BINOL)-based chiral polyimine macrocycles are an emerging class of chiral macrocycles that can be constructed by one-step aldehyde-amine condensation of BINOL derivatives with other building blocks. These macrocycles exhibit good characteristics, such as facile preparation, rigid cyclic structures, multiple chiral centers, and defined molecular cavities, that make them good candidates as new chiral recognition materials for chromatographic enantioseparations. In this study, a BINOL-based [2+2] chiral polyimine macrocycle was synthesized by one-step condensation of enantiopure (S)-2,2'-dihydroxy-[1,1'-binaphthalene]-3,3'-dicarboxaldehyde with (1R,2R)-1,2-diaminocyclohexane. The product was modified with 5-bromo-1-pentene and then attached to thiolated silica using click chemistry to construct a new chiral stationary phase (CSP). The enantioselectivity of the new CSP was explored by separating various racemates under normal phase (NP) and reversed phase (RP) high performance liquid chromatography (HPLC). Thirteen racemates and eight racemates were enantioseparated under the two separation modes, respectively, including chiral alcohols, phenols, esters, ketones, amines, and organic acids. Among them, nine racemates achieved baseline separation under NP-HPLC and seven racemates achieved baseline separation under RP-HPLC. High resolution separation was observed with benzoin (Rs = 5.10), epinephrine (Rs = 4.98), 3-benzyloxy-1,2-propanediol (Rs = 4.42), and 4,4'-dimethylbenzoin (Rs = 4.52) in NP-HPLC, and with 4-methylbenzhydrol (Rs = 4.72), benzoin ethyl ether (Rs = 3.79), 1-phenyl-1-pentanol (Rs = 3.68), and 1-(3-bromophenyl)ethanol (Rs = 3.60) in RP-HPLC. Interestingly, the CSP complemented Chiralcel OD-H, Chiralpak AD-H, and CYCLOBOND I 2000 RSP columns for resolution of these test racemates, separating several racemic compounds that could not be well separated by the three commercially available columns. The influences of injected sample amount on separation were also evaluated. It was found that the column exhibited excellent stability and reproducibility after hundreds of injections, and the relative standard deviations (n = 5) of the retention time and resolution were less than 0.49% and 0.69%, respectively. This study indicates that the BINOL-based chiral macrocycle has great potential for HPLC enantioseparation.

Multiobjective optimization of effect-directed planar chromatography as a promising tool for fast selection of polypotent natural products.

A new method for efficiently selecting polypotent natural products is proposed in this study. The method involves using effect-directed HPTLC data and multiobjective optimization algorithms to extract chromatographic signals from HPTLC bioassay images. Three different multiobjective optimization methods, namely Derringer's desirability approach, Technique for order of preference by similarity to ideal solution (TOPSIS), and Sum of ranking differences (SRD), were applied to the chromatographic signals. In combination with jackknife cross-validation, Derringer's approach and TOPSIS demonstrated high similarity in finding the best (most polypotent), next to the best, next to the worst, and worst (least polypotent) extracts, while the SRD resulted in slightly different outcomes. Furthermore, a new method for identifying the chromatographic features that characterize the most polypotent extracts was proposed. This method is based on partial least square regression (PLS) and can be used in combination with HPTLC-chemical fingerprints to predict the desirability of new extracts. The resulting PLS models demonstrated high statistical performance with determination coefficients ranging from R2 = 0.885 in the case of Derringer's desirability, to 0.986 for TOPSIS. However, the PLS modeling of SRD values was not successful.

Characterization and identification of the wide-polarity multicomponents from Prunella vulgaris by offline two-dimensional liquid chromatography and hydrophilic interaction chromatography coupled to ion mobility-quadrupole time-of-flight mass spectrometry.

Metabolites identification is crucial to develop functional foods or perform quality control. Prunella vulgaris (Xia-Ku-Cao) is a medicinal and edible plant used as the herbal medicine or main additive in functional beverage. However, current analytical strategies can only on-line characterize tens of compounds, restricted by insufficient chromatographic resolution and low coverage of the mass spectrometric scan methods. This work was designed to characterize the wide-polarity components from the ear of P. vulgaris. The total extract was fractionated by semi-preparative high-performance liquid chromatography into the retained medium-polarity fraction and unretained polar fraction, which were further analyzed by offline two-dimensional liquid chromatography (2D-LC) and hydrophilic interaction chromatography, respectively. Data-independent high-definition MSE of the Vion™ ion mobility time-of-flight mass spectrometer was utilized enabling the high-coverage acquisition of collision-induced dissociation-MS2 data. The offline 2D-LC, configuring the XBridge Amide and HSS T3 columns, gave high orthogonality (0.81) and effective peak capacity (1555). Automatic peak annotation facilitated by the UNIFI™ bioinformatics platform and comparison with 62 reference compounds achieved the efficient and more reliable structural elucidation. We could characterize 255 compounds from P. vulgaris, with numerous phenylpropanoid phenolic acids and triterpenoid O-glycosides newly reported. Especially, collision cross section (CCS) prediction and targeted isolation of three compounds assisted in the identification of 39 groups of isomers. Additionally, 17 hydrophilic compounds, involving oligosaccharides and organic acids, were characterized from the unretained polar fraction. Conclusively, the in-depth metabolites identification of P. vulgaris was accomplished, and the results can benefit the development and better quality control of this valuable plant.

Nickel oxide nanoparticles modified with dimethylglyoxime grafted on a cellulose surface as an efficient adsorbent for thin film microextraction of tramadol in biological fluids followed by its determination using HPLC.

In the current study, nickel oxide nanoparticles (NiO NPs) modified with dimethylglyoxime (DMG) were deposited onto the cellulose surface (Ni(DMG)2-NiO-Cell) and used as an efficient adsorbent for thin film microextraction (TFME) of tramadol (TRA). The extracted TRA was determined using a high-performance liquid chromatography-ultraviolet detector (HPLC-UV). NiO NPs were synthesized by co-precipitation method on the surface of the cellulose substrate; afterward, its surface was modified by DMG to increase the extraction capability of the thin film toward TRA. The synthesized NiO-Cell and Ni(DMG)2-NiO-Cell thin films were characterized using various techniques. The effect of modification of the NiO thin film with DMG reagent on the extraction efficiency was investigated. The crucial parameters influencing the extraction efficiency, including extraction time, desorption time, desorption solvent, pH and salt content, were investigated via a one-at-a-time approach. The figures of merit for the developed method were evaluated in urine, plasma, and deionized water under the optimized extraction and desorption condition. The limits of detection and limits of quantification were in the range of 0.1 to 1 ng mL-1 and 0.3 to 3 ng mL-1, respectively, for the studied samples. The linear dynamic ranges of the developed TFME-HPLC-UV method were 0.3-1000, 1-2500, and 3-5000 ng mL-1 for the deionized water, urine, and plasma samples, respectively. The reproducibility and repeatability of the developed method was assayed in terms of intra-day, inter-day, and inter-thin film precisions by conducting six-replicate experiments at the concentration level of 0.1 and 1 µg mL-1, which were in the range of 5.9% to 8.3%. The sufficiency and applicability of the developed TFME-HPLC-UV method was investigated by determining TRA in urine and plasma samples, and the resulting relative recoveries (RR%) were 85.9% and 91.7%, respectively.

Identification, characterization, and in silico ADMET prediction of nirmatrelvir and its degradation products using HPLC-PDA and LC-QTOF-MS/MS.

RATIONALE: Nirmatrelvir is a protease inhibitor that is essential for virus replication. Nirmatrelvir is indicated for the management of mild to severe cases of COVID-19 in individuals who are 12 years of age or older. Forced degradation studies of nirmatrelvir were carried out on the drug substance in solid and solution forms, subjecting it to various stress conditions according to International Conference on Harmonisation (ICH) Q1A(R2) and Q1B guidelines. The analytical method was validated as per the ICH Q2(R1) guidelines. METHODS: The drug substance (nirmatrelvir) was subjected to hydrolysis (acidic, alkaline, and neutral), thermal, photolytic, and oxidative stress conditions. Five degradation products (DPs) of nirmatrelvir formed under hydrolytic (acidic and alkaline) and oxidative (2,2-azobisisobutyronitrile) stress conditions. These degradation products were identified and separated using reverse-phase HPLC on a phenomenex kinetex C8 column (250 mm × 4.6 mm × 5 µm) with gradient elution. The mobile phase consisted of 0.1% formic acid and acetonitrile, and detection was carried out at a wavelength of 210 nm. RESULTS AND CONCLUSIONS: Nirmatrelvir and its five DPs were efficiently separated using reverse phase-HPLC. These five DPs were identified and characterized using LC-electrospray ionization (ESI)-Q-TOF-coupled mass spectrometry analysis in the ESI-positive ionization mode. The formation mechanisms of the DPs and the most probable mass fragmentation pathways for both nirmatrelvir and its DPs were elucidated. The developed method demonstrated selectivity, accuracy, linearity, and reproducibility, making it appropriate for quality control of nirmatrelvir and future research studies. Additionally, the physicochemical and Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties of nirmatrelvir and its DPs were predicted using ADMET predictor software. The toxicity profile revealed that DP2 and DP3 have teratogenic effects while DP1 and DP3 caused phospholipidosis.

Identification of active ingredients in Naomaitai capsules using high-resolution mass spectrometry unite molecular network analysis and prediction of their action mechanisms.

RATIONALE: Although Naomaitai capsule (NMC) is widely used in clinical practice and has a good curative effect for cerebral infarction, its material basis and mechanism of action remain unclear. METHODS: In this study, ultra-high-performance liquid chromatography (UHPLC) coupled with quadrupole Orbitrap MS technology was used to analyse the in vivo and in vitro components of NMC, and the Global Natural Products Social Molecular Networking website was used to further analyse the components of NMC. Next, systems biology approaches were employed to investigate the mechanism of action of NMC. Finally, molecular docking technology was used to verify the network pharmacological results. RESULTS: In total, 177 compounds were identified in vitro, including 65 terpenoids, 62 flavonoids, 25 organic acids and 11 quinones. 64 compounds were identified in the blood of mice, and the main active components included ginkgolide C, ginkgolide A, ligustilide, tanshinone IIB, olmelin, emodin and puerarin. The main targets in vivo included TP53, SRC, STAT3, PIK3CA and PIK3R1. CONCLUSIONS: In conclusion, this study has revealed that NMC acts on multiple targets in the body through various active components, exerting synergistic effects in the treatment of CI. Its mechanism of action may involve inhibiting neuronal apoptosis, oxidative stress and inflammatory responses as well as reducing cerebral vascular permeability and promoting cerebral vascular regeneration.

Advances in analytical technologies for emerging drug modalities and their separation challenges in LC-MS systems.

The last few years have seen a rise in the identification and development of bio-therapeutics through the use of cutting-edge delivery methods or bio-formulations, which has created bio-analytical difficulties. Every year, new bio-pharmaceutical product innovations come out, but the analytical development of these products is challenging. Quantifying the products and components of conjugated molecular structures is essential for preclinical and clinical research in order to guide therapeutic development, given their intrinsic complexity. Furthermore, a significant amount of information is needed for the measurement of these unique modalities by LC-MS techniques. Numerous LC-MS based methods have been developed, including AEX-HPLC-MS, RP-IP-LCMS, HILIC-MS, LCHRMS, Microflow-LC-MS, ASMS, Hybrid LBA/LC-MS, and more. However, these methods continue to face problems, prompting the development of alternative approaches. Therefore, developing bio-molecules that are this complicated and, low in concentration requires a skilled LC-MS based approach and knowledgeable personnel. This review covers general novel modalities classifications, sample preparation techniques, current status and bio-analytical strategies for analyzing various novel modalities, including gene bio-therapeutics, oligonucleotides, antibody-drug conjugates, monoclonal antibodies and PROTACs. It also covers how these strategies have been used in the past and how they are being used now to address challenges in the development of LC-MS based methods, as well as improvement strategies, current advancements and recent developed methods. We additionally covered on the benefits and drawbacks of different LC-MS based techniques for the examination of bio-pharmaceutical products and the future perspectives.

Evaluation of a point-of-care rapid diagnostic test kit (SICKLECHECK) for screening of sickle cell diseases.

Sickle cell diseases (SCD) are the most common genetic disorders with significant morbidity and mortality worldwide, including in India. The high prevalence of this disorder in many geographical regions calls for the use of a point-of-care rapid diagnostic test (RDT) for early screening and management of the diagnosed cases to reduce the allied clinical severity. In view of this, the present study was undertaken for the validation of a point-of-care RDT kit (SICKLECHECKTM) for the screening of SCD. This validation and diagnostic accuracy study was conducted among the cases advised for screening of SCD. For validation, all the recruited cases were investigated for both the SICKLECHECKTM RDT kit and HPLC (Variant-II) considering HPLC as a gold standard. A total of 400 cases were screened for both tests. For the presence and absence of sickle cell hemoglobin in the samples, SICKLECHECKTM RDT kit results showed a sensitivity and specificity of 99.39% and 98.73% respectively with references to HPLC findings. For the detection of the 'AS' pattern, the SICKLECHECKTM RDT kit has shown a sensitivity and specificity of 99.07% and 98.81% respectively. For the detection of the 'SS' pattern, the SICKLECHECKTM RDT kit has shown a sensitivity and specificity of 97.92% and 100.0% respectively. Cases with ß thalassemia trait, hemoglobin E trait, hemoglobin Lepore trait and trait for hereditary-persistence-of-fetal-hemoglobin (high HbF %) diagnosed in HPLC were resulted with 'AA' pattern in SICKLECHECKTM RDT kit. The high sensitivity and specificity of the SICKLECHECKTM RDT kit insist on its use as a point-of-care screening tool for SCD especially where there is a lack of laboratory facilities as well as in hospital-based set-up requiring immediate diagnosis and management of SCD. However, for further confirmation, the samples should be analyzed with other gold standard techniques like HPLC.

Natural deep eutectic solvent for the simultaneous derivatization and microextraction of isoniazid from human plasma.

BACKGROUND: Personalized medicine is a rapidly revolving field that offers new opportunities for tailoring disease treatment to individual patients. The main idea behind this approach is to carefully select safe and effective medications and treatment plant based on each patient's unique pharmacokinetic profile. Isoniazid is a first-line anti-tuberculosis drug that has interindividual variability in its metabolic processing, leading to significant differences in plasma concentrations among patients receiving equivalent doses. This variability necessitates the creation of individualized treatment regimens as part of personalized medicine to achieve more effective therapy. RESULTS: In this work, a deep eutectic solvent-based liquid-liquid microextraction approach for the separation and determination of isoniazid in human plasma by high-performance liquid chromatography with UV-Vis detection was developed for the first time. A new natural deep eutectic solvent based on thymol as a hydrogen bond donor and 4-methoxybenzaldehyde as a hydrogen bond acceptor was proposed as the extraction solvent. The developed microextraction procedure assumed two simultaneous processes during the mixing of the sample and extraction solvent: the derivatization of the polar analyte in the presence of 4-methoxybenzaldehyde (component of the natural deep eutectic solvent) with the formation of a hydrophobic Schiff base (1); mass transfer of the Schiff base from the sample phase to the extraction solvent phase (2). Under optimal conditions, the limits of detection and quantification were 20 and 60 µg L-1, respectively. The RSD value was <10 %, the extraction recovery was 95 %. SIGNIFICANCE: In this work, the possibility of isoniazid derivatization in the natural deep eutectic solvent phase with the formation of the Schiff base was presented for the first time. The approach provided the separation and preconcentration of polar isoniazid without the use of expensive derivatization agents and solid-phase extraction cartridges. The formation of the Schiff base was confirmed by mass spectrometry.

Performance of global retention models in the optimisation of the liquid chromatographic separation (II): Complex multi-analyte samples.

BACKGROUND: Enhancing the quality control of medicinal plants is a complex challenge due to their rich variety of chemical compounds present at varying and extreme concentrations. Chromatographic fingerprints, which have become essential for characterising these complex natural materials, require achieving optimal separation conditions to effectively maximise the number of detected peaks. The challenges in optimising fingerprints and other complex multi-analyte samples include the unavailability of standards, the presence of unknown constituents and the substantial workload that would require conventional optimisation methods based on models. RESULTS: This work introduces an interpretive optimisation approach which operates on the premise of predicting chromatograms using global models. Initially, a multi-linear gradient experimental design is sequentially executed to accommodate all peaks in the chromatogram in an adequate time window. Following this, a small set of sample peaks (reference peaks) is selected based on their consistent traceability across all chromatograms in the design. Using this reference dataset, a global model is constructed, initially focused solely on the reference peaks and later extended to encompass all detected peaks in the sample. The aim is to find gradients that maximise resolution while minimising analysis time. These optimised gradients are applied successfully to enhance the separation of medicinal plant extracts, with particular emphasis on peppermint and pennyroyal extracts. SIGNIFICANCE: The proposed optimisation relying on global models can be applied to highly complex samples even in the absence of standards, or in cases where standards are available but their use is impractical due to workload constraints. Moreover, in discerning the most promising gradients for highly complex samples, peak purity has demonstrated superior reliability and competitiveness compared to peak capacity as chromatographic objective function.

Eco-friendly one-step egg white gel preparation for sensitive detection of 13 trichothecenes in oats using UHPLC-MS/MS.

Oat products have gained widespread recognition as a health food due to their rich and balanced nutritional profile and convenience. However, the unique matrix composition of oats, which differs significantly from other cereals, presents specific challenges for mycotoxin analysis. This study presents an ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method enhanced with an innovative egg white gel pretreatment for the simultaneous analysis of 13 regulated and unregulated trichothecenes in oats. The method demonstrated excellent performance with high accuracy (> 87.5%), repeatability (< 5.7%), and reproducibility (< 8.1%). Analysis of 100 commercial oat products revealed a concerning detection rate (78%) for at least one of the 11 trichothecenes investigated. Notably, deoxynivalenol, exceeding the standard limit in 2% of samples, exhibited the highest detection rate (62%). Additionally, concerning co-occurrence patterns and positive correlations were observed, highlighting potential synergistic effects. The first-time detection of unregulated mycotoxins (T-2 triol, 4,15-diacetoxyscirpenol, 15-acetoxyscirpenol, and neosolaniol) underscores the need for comprehensive monitoring. This method, while developed for oats, shows potential for broader application to other cereals, though further investigation and confirmation are necessary. These findings suggest a potentially underestimated risk of trichothecenes in oats, necessitating continuous monitoring to ensure consumer safety.

Metabolic profiling of different parts of Physalis alkekengi L. var. franchetii (Mast.) Makino based on UPLC-Q-Orbitrap-HRMS coupled with bioactivity assays.

Physalis alkekengi L.var. franchetii (Mast.) Makino (PAF) is an important edible and medicinal plant resource in China. Historically, phytochemical studies have primarily examined the calyx and fruit due to their long-standing use in traditional Chinese medicine for their ability to clear heat and detoxify. Metabolites and bioactivities of other parts such as the leaves, stems and roots, are rarely studied. The study involved conducting metabolic profiling of five plant parts of PAF using UPLC-Q-Orbitrap-HRMS analysis, in conjunction with two bioactivity assays. A total of 95 compounds were identified, including physalins, flavonoids, sucrose esters, phenylpropanoids, nitrogenous compounds and fatty acids. Notably, 14 aliphatic sucrose esters, which are potentially novel compounds, were initially identified. Furthermore, one new aliphatic sucrose ester was purified and its structure was elucidated by 1D and 2D NMR analysis. The hierarchical clustering analysis and principal component analysis showed the close clustering of the root and stem, suggesting similarities in their chemical composition, whereas the leaf, calyx and fruit clustered more distantly. Orthogonal partial least-squares discriminant analysis results showed that 41 compounds potentially serve as marker compounds for distinguishing among plant parts. Variations in activity were observed among the plant parts during the comparative evaluation with biological assays. The calyx, leaf and fruit extracts showed stronger antibacterial and anti-inflammatory activities than the stem and root extracts, and 19 potential biomarkers were identified by S-plot analysis for the observed activities, including chlorogenic acid, luteolin, cynaroside, physalin A, physalin F, physalin J, apigetrin, quercetin-3ß-D-glucoside and five ASEs, which likely explain the observed potent bioactivity.

Development of an integrated strategy for comprehensive characterization of Sinomenii Caulis extract and metabolites in rats based on UPLC/Q-TOF-MS.

Sinomenii Caulis (SC), a commonly used traditional Chinese medicine for its therapeutic effects on rheumatoid arthritis, contains rich chemical components. At present, most studies mainly focus on sinomenine, with little research on other alkaloids. In this study, a comprehensive profile of compounds in SC extract, and biological samples of rats (including bile, urine, feces, and plasma) after oral administration of SC extract was conducted via ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS). The fragmentation patterns and potential biotransformation pathways of six main types of alkaloids in SC were summarized, and the corresponding characteristic product ions, relative ion intensity, and neutral losses were obtained to achieve rapid classification and identification of complex components of SC from in vitro to in vivo. As a result, a total of 114 alkaloid compounds were identified, including 12 benzyl alkaloids, 4 isoquinolone alkaloids, 32 aporphine alkaloids, 28 protoberberine alkaloids, 34 morphinan alkaloids and 4 organic amine alkaloids. After administration of SC extract to rats, a total of 324 prototypes and metabolites were identified from rat plasma, urine, feces and bile, including 81 aporphines, 95 protoberberines, 117 morphinans and 31 benzylisoquinolines. The main types of metabolites were demethylation, hydrogenation, dehydrogenation, aldehydation, oxidation, methylation, sulfate esterification, glucuronidation, glucose conjugation, glycine conjugation, acetylation, and dihydroxylation. In summary, this integrated strategy provides an additional approach for the incomplete identification caused by compound diversity and low abundance, laying the foundation for the discovery of new bioactive compounds of SC against rheumatoid arthritis.

Stability Indicating UPLC Method Development and Validation for the Quantitative Estimation of Pazopanib in Pure form and Marketed Pharmaceutical Dosage form.

An analytical, accurate, precise, specific, efficient and simple Ultra-Performance Liquid Chromatography method has been developed and validated for the determination of Pazopanib in bulk and was applied on marketed Pharmaceutical Dosage form. The mobile phase used for the chromatographic runs consisted of 0.1% OPA Buffer and Acetonitrile in the ratio of 30:70% v/v. The separation was achieved on a BHEL UPLC column using isocratic mode. Pazopanib Drug peak were well separated and were detected by a PDA detector at 256 nm. The developed method was linear at the concentration range 6-14 µg/ml for Pazopanib. The method has been validated according to ICH guidelines with respect to system suitability, specificity, precision, accuracy and robustness. The LOD and LOQ for the Pazopanib were found to be 0.5853 µg/ml and 1.7738µg/ml respectively. The developed method is simple, precise, specific, accurate and rapid, making it suitable for estimation of Pazopanib in bulk and marketed pharmaceutical dosage form dosage form.

An LC-MS/MS method for the determination of Lifitegrast in human plasma and tear and its application in the pharmacokinetic study.

Aim: A new, selective and simple UPLC-MS/MS method was developed and validated for the determination of lifitegrast in human plasma and tear in order to obtain PK data. Materials & methods: Lifitegrast-d4 solutions were added in the samples, and then were extracted and transferred to a UPLC vial. Results: The respective working ranges were 25.00-2000.00 pg/ml in plasma and 4.00-1000.00 µg/ml in tear. The fully validated method complied with existing regulatory criteria for accuracy and precision, recovery, etc. It was applied to plasma and tear samples, which were from a clinical study, successfully. Conclusion: This method is useful in the evaluation of lifitegrast in plasma and tear.

[Box: see text].

[Research on bitter taste and efficacy of Ginkgo biloba extract based on UPLC-Q-TOF-MS~E integrated with molecular docking].

Based on high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF-MS~E) and molecular docking technique, bitter compounds of Ginkgo biloba extract(GBE) were characterized, and their relationship with bitter efficacy was investigated. Firstly, UPLC-Q-TOF-MS~E was used for qualitative analysis of GBE components, and 60 chemical components were identified. These chemical components were molecular-docked with bitter receptors, and 26 bitter substances were selected, mainly flavonoids. Secondly, sensory and electronic tongue bitterness evaluation techniques were used to verify that total flavones of GBE were the main bitter substances, which was consistent with the molecular docking results. Finally, network pharmacology was used to predict and analyze bitter substances. The relationship between the target of bitter substance and bitter effect was explored. The key targets of bitter substances are CYP2B6, ALOX15, and PTGS2, etc., and bitter substances may exert a bitter efficacy by ac-ting on related disease targets, indicating that bitter substances of GBE are the material basis of the bitter effect. In summary, the study indicated that the molecular docking technique had a guiding effect on the screening of bitter substances in traditianal Chinese medicine(TCM), and bitter substances of GBE had a bitter efficacy. It provides ideas and references for the study of the "taste-efficacy relationship" of TCM in the future.

[Chemical composition analysis of Ganoderma lucidum based on UPLC-Orbitrap-HRMS and virtual screening of FXR activators for treatment of liver fibrosis].

The chemical composition of Ganoderma lucidum ethanol extracts was systematically analyzed and identified by ultra-high performance liquid chromatography-quadrupole electrostatic field orbitrap high-resolution mass spectrometry(UPLC-Orbitrap-HRMS). The fragmentation pattern of the representative chemical compounds was summarized, and the potential anti-liver fibrosis active compounds of G. lucidum acting on the farnesoid X receptor(FXR) target were studied to elucidate its pharmacodynamic substance basis. Preliminarily, 95 chemical constituents of G. lucidum ethanol extracts were identified, including 24 ganoderic acids, 9 ganoderenic acids, 13 lucidenic acids, 3 ganolucidic acids, 1 ganoderma lactone, 40 other triterpenoids, 4 fatty acids, and 1 other constituent. In addition, the fragmentation patterns of the representative compounds were also analyzed. The structural characteristics of ganoderic acids and ganoderenic acids were the C30 skeleton, containing free-COOH and-OH groups, which could easily lose H_2O and CO_2 to form fragment ions. The D-ring was mostly a five-membered ring, which was prone to breakage. Lucidenic acids were the lanosterolane-type of the C27 skeleton, and the side-chain structure became shorter and contained the same free-COOH and-OH compared with ganoderic acids, which had been reduced from 8 to 5 cartons and prone to lose H_2O and CO_2. Then, six reported FXR receptor agonists were selected to form a training set for establishing a pharmacophore model based on FXR ligands. The 95 identified chemical constituents of G. lucidum were matched with the pharmacophore, and the optimal pharmacophore model 02(sensitivity=0.750 00, specificity=0.555 56, ROC=0.750) was selected for the virtual screening of the G. lucidum compound library through the validation of the test set. Finally, 31 potential G. lucidum active constituents were screened and chosen to activate the FXRs. The ADMET results showed that ganoderic acid H and lucidenic acid J had less than 90% plasma protein binding rate and no hepatotoxicity, which could be used as FXR activators for developing clinical drugs for the treatment of liver fibrosis, either alone or in combination.

Flavonoid Profiles in the Pulp of Different Lemon Cultivars and Their Antioxidant Activity Based on UPLC-Q-TOF-MS.

Previous studies have indicated that there may be differences among the varieties of lemon flavonoids, but the details have not yet been made clear, which limits the comprehensive use of different cultivated lemon varieties. In this study, ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) and ultraviolet-visible spectroscopy (UV-Vis) were used to investigate the types and contents of flavonoids in the flesh of the main cultivated variety (Eureka) and five common lemon varieties, as well as their in vitro antioxidant activity. A total of 21 compounds were identified, five of which were common compounds. Among them, Verna, Lisbon, and Bearss each have characteristic components that can serve as potential criteria for variety identification. Each of the six varieties of lemon has strong antioxidant activity. The antioxidant activity of different lemon varieties is related to flavonoids. Therefore, Eureka and the other five varieties of lemon are good natural antioxidants, and the cultivation and industrial production of lemons should consider the needs and selection of suitable varieties.

Method Development and Validation of an Aerosol Sampling Technique for the Analysis of Nicotine in Electronic Cigarette Aerosols.

Because of the increasing popularity of e-cigarettes, monitoring the e-cigarette market has become important for national health authorities to guarantee safety and quality. In the EU, the Tobacco Products Directive requires emission studies for e-cigarette products. The absence of industry guidelines for studying these emissions and the lack of proper validation in the literature led us to develop and validate a method using the total error approach for the determination of nicotine in e-cigarette aerosols. A commercial vaping device was used to generate aerosols, which were then collected on Cambridge filter pads and measured for nicotine concentration by UHPLC-DAD after extraction. The method was successfully validated by generating accuracy profiles, which show that the ß-expectation tolerance intervals remained below the acceptance limits of ±20%. Within-run repeatability and intermediate precision were considered acceptable since the highest RSD value obtained was below 5%. The method was applied to 15 commercial e-liquids. A complete validation of a method for the analysis of e-cigarette emissions is presented, including several parameters that impact the accuracy and reproducibility. Similar systematic approaches for method development and validation could be used for other e-cigarette emission analysis methods to ensure the reliability of the measurements.