Pheophorbide A, a chlorophyll degradation product, exhibits various pharmacological activities and is a good candidate for photodynamic therapy of various tumors as second-generation photosensitizer. In this study, the analytical method was developed and validated to quantify pheophorbide A in biological samples and to assess its absorption, distribution, and excretion in mice. A sensitive, simple, and reliable liquid chromatography-high resolution mass spectrometry method was developed using protein precipitation method as sample preparation procedure, and showed linearity over the concentration range of 1- 500 ng/mL (r = 0.9966), with an intra- and inter-day accuracy and precision at four quality control levels of 93.3-110.0% and 3.5-13.5%, respectively. After an intravenous (2.5 mg/kg) and oral (5 mg/kg) administration of pheophorbide A to male ICR mice, its fecal recoveries for 48 h were 3.2% and 16.3% of the administered dose, respectively, but it was not excreted in the urine. Pheophorbide A showed high volume of distribution at steady state, low oral bioavailability (13.2%), low total recovery, and the delayed time to maximum plasma concentration, indicating the extensive tissue distribution and systemic clearance via the metabolism.
Antibody-drug conjugates (ADCs) have emerged as a powerful class of targeted therapeutics, integrating the selectivity of monoclonal antibodies with the cytotoxic potency of small-molecule payloads. Accurate quantification of payloads within ADCs is essential for evaluating conjugation efficiency, stability, and drug-to-antibody ratio (DAR), yet remains challenging due to the structural heterogeneity and complexity of conjugation chemistry. In this study, an LC-MS/MS based analytical workflow was developed and validated using IgG-FITC as an ADC-like model to establish a practical approach for payload detection and quantification. The workflow consisted of six systematic steps: characterization of free payload fragments, enzymatic digestion of the ADC, verification of overlapping m/z ions between free and conjugated forms, confirmation of their absence in native IgG peptides, construction of an MRM calibration curve, and quantitative evaluation of digested samples. This stepwise approach provides a robust, reproducible, and transferable framework for developing LC-MS/MS methods applicable to payload quantification and characterization in ADC systems, while ensuring methodological reliability and safety during early-phase analytical development.
Mistletoe (Dendrophthoe pentandra (L.) Miq.) is a parasitic plant commonly found on teak trees and has been traditionally used to treat various ailments. This species contains bioactive compounds with significant pharmacological activities, including potential anti-cancer properties. In this study, mistletoe leaf extracts were obtained through maceration using n-hexane as the solvent. Toxicity testing was conducted on Artemia salina larvae using the Brine Shrimp Lethality Test (BSLT), and bioactive compounds were identified through gas chromatography-mass spectrometry (GC-MS) analysis. In silico anticancer activity was assessed using molecular docking, targeting sirtuin 1 (SIRT1) receptors. The toxicity test revealed an LC50 value of 14.38 ppm, indicating strong bioactivity and high toxicity potential. GC-MS analysis identified three major compounds with potential antioxidant and anti-cancer activities: phytol, octadecanoic acid, and n-hexadecanoic acid. Molecular docking results showed that phytol exhibited the highest binding affinity to the SIRT1 receptor at -7.3 kcal/mol, followed by octadecanoic acid and n-hexadecanoic acid, both at -6.4 kcal/mol. These three compounds are predicted to inhibit SIRT1 activity, a key protein involved in the of cancer cells, their as natural anti-cancer agents.
Isotopic analysis of ultra-trace uranium particles for nuclear safeguards requires the highest level of accuracy and reliability. Previously, uranium isotope ratios in NUSIMEP-7 (the 7th Nuclear Signatures Interlaboratory Measurement Evaluation Programme; an interlaboratory comparison/proficiency-test exercise for uranium microparticles) particles were determined using thermal ionization mass spectrometry (TIMS) with an optimized static detection method, yielding satisfactory results. However, the data integration procedure can also significantly influence the final analytical results, especially for ultra-trace level samples analyzed by the continuous heating method. In this study, raw data from the original NUSIMEP-7 particle analysis were retrospectively re-processed using a recently optimized data integration protocol: 'Method I' (Summed Intensity Ratio), with an 'over 25%' signal integration range. The results showed improvements in accuracy for all isotope ratios. Most notably, the z-scores and zeta-scores, which are critical for interlaboratory comparison programs, were significantly improved, moving from 'acceptable' or 'warning' levels to 'excellent'. For the key n( U)/n( U) ratio, the z-score improved from 1.9 to-0.66, and the zeta-score improved from 1.3 to-0.12. This study demonstrates that applying optimized data processing protocols, even retrospectively, can significantly enhance the fidelity and reliability of ultra-trace isotopic analyses.
The recent emergence of large language models (LLMs) has transformed the process of machine learning (ML) model development, markedly reducing the need for advanced coding expertise and enabling domain scientists to directly construct computational workflows through natural language prompts. In this study, we demonstrate the application of Google Gemini Pro 2.5 for developing classification models of erectile dysfunction (ED) drug analogues using tandem mass spectrometric (MS/MS) data. The dataset consisted of 149 compounds, including sildenafil, vardenafil, tadalafil analogues, and structurally unrelated compounds, represented as binary barcode spectra (m/z 50-800) derived from fragment ion intensities. Through stepwise prompting, the LLM generated executable Python code for data preprocessing, model construction, hyperparameter optimization, and ensemble learning using random forest, artificial neural networks (ANN), and support vector machines (SVM). The resulting models achieved high classification performance comparable to that of a manually programmed ANN reported in our previous work, while requiring markedly less programming effort. Beyond reproducing classification accuracy, this study highlights the efficiency, accessibility, and reproducibility of LLM-assisted ML workflows, underscoring their potential to democratize computational methods in mass spectrometry and analytical chemistry.
Accurate identification of volatile organic compounds (VOCs) generated at fire scenes is essential not only for determining the cause of ignition but also for environmental and toxicity risk assessments. In this study, we applied gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) in parallel and introduced pretreatment methods suitable for each analyzer to expand the detection range of VOCs. Samples collected in adsorption tubes using thermal desorption were analyzed by GC-MS, and residual samples from the same adsorption tubes were extracted with solvents and analyzed by LC-MS. As a result, a maximum of 238 compounds were detected by GC-MS analysis, and 12 types of hazardous chemicals were commonly identified in all samples. In the LC-MS analysis, a total of more than 950 organic compounds were detected, of which 482 compounds were commonly identified in all samples. In particular, compounds with biological accumulation and endocrine disruption potential, such as 4-octylphenol and DEHP, were detected only in the LC-MS analysis. It was confirmed that the five compounds detected in both analyses could be used as cross-validation indicators. The sequential analysis strategy using GC-MS and LC-MS with the same collection tube improved both analytical reproducibility and efficiency, demonstrating its potential for application in various fields such as chemical accident response, forensic analysis, and environmental risk assessment.
Okra (Abelmoschus esculentus (L) Moench) is a common vegetable cultivated in warm climate regions. It is also a valuable medicinal plant whose potential health benefits are related to the presence of phenolic compounds, e.g. flavonoids. However, the published results concerning the most abundant flavonoids present in okra fruits are often inconsistent or disputable. Therefore, we have decided to perform the HPLC-MS analysis of okra fruit extract in order to identify the most abundant flavonoid glycosides. The structures of the flavonoid glycosides have been mainly elucidated on the basis of m/z values and relative abundances of [M+/-H] - precursor ions and Y , [Y -H] product ions. We have identified five compounds, quercetin 3-O-glucoside and its four conjugates, which is consistent with part of the literature data, as discussed in details.
A selective and robust High Performance Liquid Chromatography (HPLC) method was developed for the separation and quantification of futibatinib, which is a novel irreversible fibroblast growth factor receptors (FGFRs) inhibitor, and its known impurities. The method optimization involves the evaluation of various chromatographic parameters, and results proved that the Kinetex C18 column and an isocratic mobile phase of acetonitrile and aqueous phosphate buffer (pH 4.1, 65:35 v/v) at 0.8 mL/min were optimal for the resolution of futibatinib and its impurities. The forced degradation studies reveal the susceptibility of futibatinib towards acidic and oxidative conditions. The degradation follows pseudo-first-order kinetics, with maximum degradation recorded under acidic conditions (k = 0.0413 h , t = 16.78 h) and then by oxidative stress (k = 0.0331 h , t = 20.93 h). Five major Degradation Products (DPs) were identified in which DP 1 (m/z 319.7691) is a vinyl halide produced through Markovnikov-type electrophilic addition, DP 2 (m/z 391.3912) is a bis-hydroxy derivative produced through oxidative demethylation, DP 3 (m/z 365.968) and DP 4 (m/z 296.2975) are the products of acid-induced hydrolysis and ring cleavage whereas DP 5 (m/z 433.4311) is a nitroso-derivative produced through oxidative modification of the amine group. The in-silico toxicity predictions classify all DPs under toxicity class 4, indicating consistent neurotoxic and carcinogenic potential, whereas DP 4 and 5 show mutagenic and immunotoxin risks. This study offers the first comprehensive degradation profiling of futibatinib by providing a stable analytical platform for quality control, regulatory compliance, and formulation stability.
Lipidomics, an emerging field, focuses on the comprehensive analysis of lipid species. However, despite its advances, non-targeted lipidomics approaches continue to encounter significant challenges in lipid annotation, primarily due to the limited coverage of publicly available tandem mass spectrometry spectral libraries. Therefore, this study aims to introduce a non-targeted lipidomics approach using molecular networking to enhance neutral lipid identification. Collision energy conditions were first optimized using commercial neutral lipid standards and subsequently validated with National Institute of Standards and Technology Standard Reference Material 1950 Metabolites in Frozen Plasma. A normalized collision energy of 30, combined with Global Natural Products Social Molecular Networking parameters (cosine score of 0.7 and a minimum of six matched fragment ions), enabled effective spectral connectivity and improved neutral lipid detection. Among the scan ranges tested, the 600-1000 m/z range was the most effective, facilitating comprehensive detection of diglycerides, triglycerides, and cholesteryl esters. This study presents an optimized molecular networking strategy for non-targeted lipidomics that enhances both lipid annotation and structural characterization.
Spilanthes acmella var calva popularly known as 'Marauti' in Nepal, are widely used by different communities as the food ingredients in their traditional cuisines. It displays a unique tingling sensation mainly due to N-alkylamides when applied to mucosal surfaces. Spilanthes served as a remedy for alleviating toothache, throat infections and other oral ailments. NAlkylamide profilings of Spilanthes extracts were performed using a gradient reversed phase high performance liquid chromatography/ electrospray ionization ion trap mass spectrometry (HPLC/ESI-MS) method. A total of 33 peaks were analyzed and 16 N-alkylamides were identified. Seven compounds (1, 5, 6, 8, 15, 16 and 25) were N-isobutylamides and nine compounds (4, 7, 10, 11, 12, 14, 17, 18 and 20) were 2-phenylethylamides.
Natural gas has become an indispensable energy source for daily life, but natural gas leakage brings great harm to both residents' life and property as well as the atmospheric environment. The severe harm caused by natural gas leakage can be prevented by taking appropriate measures during the early stages of the leak. In this paper, proton transfer reaction mass spectrometer (PTR-MS) was used to detect the standard gas of simulated natural gas components by using a new reagent ion, CF3+ ion. The study demonstrates that CF3+ ions can chemically react with ethane in natural gas, resulting in the production of C2H5+ and F+(C2H6) ions. By plotting the standard curve, the detection limits of m/z 29 and 49 product ions were calculated to be 6.251 mu g/m(3) and 6.87 mu g/m(3), respectively, with the relative standard deviations (RSDs) ranging from 1.8% to 3.5%. It can fully meet the demand of early trace leakage detection of natural gas, and greatly improve the early warning capability of natural gas leakage, and provide reliable protection of the residents' life and property as well as the atmospheric environment. It also provides a new research method for early warning detection of natural gas leakage.
RNA therapeutics and mRNA vaccines have emerged as a promising class of medicines for the treatment of various diseases. The successful application of these modalities depends on the safe and effective delivery of mRNA into target cells. Lipid nanoparticle (LNP) is a novel carrier for delivery. Ionizable lipid is a key component of LNP and plays a crucial role in encapsulating and protecting mRNA molecules. Given the incorporation of novel carrier components, such as synthetic lipids, in LNPs, extensive preclinical biodistribution studies are essential to evaluate their in vivo exposure profiles. To assess the biodistribution of ionizable lipids, an analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the quantitation of ionizable lipids such as SM-102 and ALC-0315, enabling their precise quantification in biological matrices. The method was successfully established, demonstrating good selectivity, linearity (r(2) >= 0.9950 over the range of 12000 ng/mL), accuracy (ranging from 89.7% to 117.4% for SM-102, from 93.8% to 115.2% for ALC-0315), precision (<= 19.7% for SM-102, <= 15.3% for ALC-0315), and a lower limit of quantification (1.0 ng/mL). This method is expected to contribute to the comprehensive evaluation of biodistribution for novel ionizable lipids in LNP formulations.
Chrozophora brocchiana is widely used in traditional medicine in Niger. In this study, hexanic, DCM, AcOEt, and EtOH-H2O (70:30) fractions of Chrozophora brocchiana aerial parts were analyzed via ultra-high-performance liquid chromatography with high-resolution mass spectrometry (UHPLC-HRMS)-based metabolomics. We explore chemical space with an advanced Global Natural Product Social (GNPS)-based molecular networking (MN) analysis tool, MolNetEnhancer. As result, three superclasses were identified (phenylpropanoids and polyketides; lipids and lipid-like molecules; organoheterocyclic compounds). Flavonoids were the most dominant class, followed by tannins, lipids, and lipid-like molecules, and alkaloids. Additionally, some compounds' putative structure and molecular formula were manually determined. This novel mapping of the metabolomic landscape of C.brocchiana provides actionable insights into plant biochemistry and justifies certain medicinal uses.
This study investigated the biodegradation of petroleum hydrocarbons by marine bacterial isolates obtained from Paotere Port. The objective was to assess the efficacy of these isolates in degrading petroleum hydrocarbons using gas chromatography-mass spectrometry (GC-MS) along with emulsification index and surface tension tests. The experiments were conducted in a microcosm designed to simulate the bacteria's natural environment, incorporating sediment, natural seawater (ALN), and petroleum. Emulsification index and surface tension measurements were taken every five days. On the 30th day of incubation, a qualitative analysis using GC-MS was performed to evaluate the extent of hydrocarbon degradation. The highest emulsification index recorded was 53.84%, while the lowest surface tension observed was 22.16 dyne/cm. GC-MS chromatograms revealed significant hydrocarbon degradation, as indicated by the breakdown of carbon chains in the sample compared to the control. The bacterial isolates from Paotere Port demonstrated the capability to degrade carbon chains up to C150. These findings demonstrate the potential of petroleum-degrading bacteria from Paotere Port as effective bioremediation agents.
: Neuropeptides, particularly in tissues, can be difficult to detect due to their low amounts and similar structures to precursors. With matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS), conventional organic acid matrices are used to help ionize analytes but can cause matrix interference in the m/z range of common neuropeptides. The high-resolution of Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) enables distinguishing matrix-derived signals from those of neuropeptides. Another benefit to FTICR MS is the ability to process transients in multiple modes, magnitudemode and absorption-mode. Using the dried droplet method, leucine enkephalin (LE) samples containing gluten exorphin B5 (B5) internal standard were deposited onto surfaces with a siloxane grid; a stainless-steel target plate (SUS), indium-tin oxide (ITO) slide, and glass slides were used. To improve the crystallization of CHCA, freeze drying was employed. Calibration curves of LE had an R of 0.88 to 0.93 when processed in magnitude-mode or post-processed in absorption-mode when spotted on SUS, ITO slides, or glass slides. Slopes were nearly equal whether processed in absorption- or magnitude mode and did not impact the limit of detection. However, the nature of substrate impacted calibration curve slopes, with ITO slides providing the steepest slope, followed by non-conductive glass, with stainless steel exhibiting the shallowest slopes and sensitivity. Peak shape was improved in absorption-mode (2.5-2.6x improvement of resolution and 1.9-2.9x improvement of S/N), suggesting that absorption-mode processing should be employed in quantitative FTICR MS applications.
In this work, we have studied the synthetic insecticides imidacloprid and chlordimeform on both oxidized and metal- lic tungsten thermoemitters in electric fields of E<10(5) V/cm using surface (thermal) ionization mass spectrometry. Imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazol-2-ylideneamine) is a neurotoxic insecticide of the neonicotinoid family and is one of the most widely used in agriculture. Chlordimeform is a carboxamidine, classified as both a formamidine insecticide and acaricide, as well as a member of monochlorobenzenes. The experiments were conducted using the MI 1201 B magnetic static mass spectrometer, which was specifically modified for the surface ionization method. The studied samples were efficiently ionized on the oxidized thermoemitter, and the mass spectra consisted of M+ , [M-H](+) , [M-H-2nH](+) and [M-R](+) ions. On the metallic ther- moemitter, the mass spectra consisted of fewer lines compared to those obtained on the oxidized surface, indicating that no addi- tional ions were generated. The mechanisms of ion formation on both oxide and metallic surfaces were discussed. For the first time, the ionization energies of the major ions of the studied compounds were evaluated using the surface ionization method, as well as the heat of sublimation of the molecules. Unimolecular decays were detected in the mass spectrum of chlordimeform. The surface ionization mass spectrometry data of samples was compared with the gas chromatography-mass spectrometry data.
Plants are excellent sources of secondary metabolites that have been used for the treatment of human diseases. This study aimed to identify bioactive compounds from the different parts of the combination of medicinal plants from the ethanolic extract. The Selected medicinal plants are leaves of Gymnema sylvestre(GS), Seed of Eugenia jambolana(EJ), Flower of Senna auriculata(SA) and Stem of Cissus quadrangularis(CQ) contain different types of phytochemicals like phenols, steroids, flavonoids, alkaloids and tannins. All four plants were combined to make a five combination GE (GS and EJ), SC (SA and CQ), SE (SA and EJ), EC (EJ and CQ) and GS (GS and SA). The present investigation was carried out to determine the bioactive compounds present in the different plant parts of selected medicinal plants by gas chromatography-mass spectrometry (GC-MS) technique. Three compounds were found in SC, 4 compounds were found in SE, 1 compound were found in EC, 3 compounds were found in GE and 6 compounds were found in GS. These are important bioactive compounds Ethane,1,1-Diehoxy, Diethyl Phthalate, 3-O-Methyl-D-Glucose, n-Hexadecanoic acid, 1-butanol,3-Methyl, Resorcinol. As a result, the ethanolic extracts of the combination of medicinal plants may have chemopreventive, anti-cancer, anti-microbial, antioxidant, anti-diabetic, antiinflammatory, and antifungal properties. These phytochemicals are recommended for traditional usage in many disorders.
Dexamethasone (DEX) is a glucocorticoid commonly used to treat idiopathic sudden sensorineural hearing loss (ISSNHL) and inner ear disorders like Meniere's disease. However, systemic administration of DEX is associated with significant side effects, such as hypertension and peptic ulcer, highlighting the need for safer and more effective intratympanic (IT) formulations and reliable methods for their in vivo evaluation. However, methods to determine DEX in the cochlea require a tissue lyser, uncommon in laboratories for instrumental analyses, and their analytical performances have not been validated. To address these issues, a simple and cost-effective method to determine DEX in murine cochlear tissue was developed using triamcinolone acetonide as the internal standard (IS), acetonitrile as a single extraction solvent, and LC-MS/MS as an instrumental method. The developed method was successfully validated through selectivity, linearity (r(2) >= 0.999 within 1-500 ng/mL), accuracy (ranging from 86.8% to 100.2%), precision (<= 5.8%), matrix effect (91.56% to 104.46%), recovery (93.1% to 104.5%) and the lower limit of quantitation (1.0 ng/mL) following FDA guidelines. This method is expected to contribute to the development of novel formulations for IT delivery of DEX for inner ear disorders.
This study investigated the impact of red ginseng extract (RGE) on the pharmacokinetics of nifedipine (NFD) and its primary metabolite, dehydronifedipine (DHNFD), in rats. A sensitive and robust analytical method was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the quantification of NFD and DHNFD in rat plasma. The method demonstrated high and reproducible extraction recovery rates, ranging from 84.50% to 91.06%, with no interference at the elu- tion peaks for NFD and DHNFD. Calibration curves for NFD (1-500 ng/mL) and DHNFD (0.3-50 ng/mL) exhibited linearity (r(2) > 0.984) and met standard criteria for inter- and intra-day accuracy, precision, and stability. Following an intravenous dose of NFD (0.2 mg/kg), no significant differences in the plasma concentrations of NFD and DHNFD were observed between the RGE-treated group (1.5 g/kg/day for 1 week) and the vehicle-treated group. However, after oral administration (1.0 mg/kg), the RGE-treated group exhibited increased plasma levels of NFD and decreased levels of DHNFD, indicating a distinct effect of RGE on oral, but not intravenous, NFD pharmacokinetics. While hepatic Cyp3a expression remained unchanged following RGE treatment, there was a reduction in Cyp3a levels in the enterocytes, suggesting that this downregulation in the gastrointestinal tract likely contributed to the altered pharmacokinetic profile observed with orally administered NFD. In conclusion, RGE administration affects the metabolism of NFD following its oral dosing, potentially through down regulation of intestinal Cyp3a protein levels, leading to reduced systemic DHNFD concentrations and increased NFD plasma exposure.
Magnolin, a bioactive lignan separated from Flos Magnoliae, possesses anti-inflammatory, anticancer, antioxidant, and vasodilator effects. This study compared the metabolic profiles of magnolin in human and rat hepatocytes using liquid chromatography-high resolution mass spectrometry. The hepatic extraction ratio of magnolin in human and rat hepatocytes were 0.27 and 0.14, respectively, suggesting that it undergoes a low-to-moderate degree of hepatic metabolism. During metabolism in human hepatocytes, magnolin generated 8 phase 1 metabolites, including O-desmethylmagnolin (M1-M4), hydroxymagnolin (M5), di-O-desmethylmagnolin (M6 and M7), and hydroxy-O-desmethylmagnolin (M8), and 11 phase 2 metabolites, including glucuronides of M1-M4 (M9-M12) and M7 (M15), sulfates of M1, M2, M6, and M7 (M13, M14, and M16-M18), and M6 disulfate (M19). However, 6 phase 1 metabolites (M1-M5 and M8) and 6 phase 2 metabolites (M9-M14) were formed after incubation of magnolin with rat hepatocytes. These findings help to predict the pharmacokinetics and metabolism of magnolin in humans.
