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Keywords = ion-pair liquid chromatography

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15 pages, 2382 KB  
Article
Study of Metabolite Detectability in Simultaneous Profiling of Amine/Phenol and Hydroxyl Submetabolomes by Analyzing a Mixture of Two Separately Dansyl-Labeled Samples
by Sicheng Quan, Shuang Zhao and Liang Li
Metabolites 2025, 15(8), 496; https://doi.org/10.3390/metabo15080496 - 23 Jul 2025
Viewed by 552
Abstract
Background: Liquid chromatography-mass spectrometry (LC-MS), widely used in metabolomics, is often limited by low ionization efficiency and ion suppression, which reduce overall metabolite detectability and quantification accuracy. To address these challenges, chemical isotope labeling (CIL) LC-MS has emerged as a powerful approach, offering [...] Read more.
Background: Liquid chromatography-mass spectrometry (LC-MS), widely used in metabolomics, is often limited by low ionization efficiency and ion suppression, which reduce overall metabolite detectability and quantification accuracy. To address these challenges, chemical isotope labeling (CIL) LC-MS has emerged as a powerful approach, offering high sensitivity, accurate quantification, and broad metabolome coverage. This method enables comprehensive profiling by targeting multiple submetabolomes. Specifically, amine-/phenol- and hydroxyl-containing metabolites are labeled using dansyl chloride under distinct reaction conditions. While this strategy provides extensive coverage, the sequential analysis of each submetabolome reduces throughput. To overcome this limitation, we propose a two-channel mixing strategy to improve analytical efficiency. Methods: In this approach, samples labeled separately for the amine/phenol and hydroxyl submetabolomes are combined prior to LC-MS analysis, leveraging the common use of dansyl chloride as the labeling reagent. This integration effectively doubles throughput by reducing LC-MS runtime and associated costs. The method was evaluated using human urine and serum samples, focusing on peak pair detectability and metabolite identification. A proof-of-concept study was also conducted to assess the approach’s applicability in putative biomarker discovery. Results: Results demonstrate that the two-channel mixing strategy enhances throughput while maintaining analytical robustness. Conclusions: This method is particularly suitable for large-scale studies that require rapid sample processing, where high efficiency is essential. Full article
(This article belongs to the Special Issue Method Development in Metabolomics and Exposomics)
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11 pages, 1107 KB  
Article
Content Determination and Impurity Profiling of Compound Glycyrrhizin Tablets by Ion-Pair High-Performance Liquid Chromatography, Coupled with Corona-Charged Aerosol Detector
by Limin Zuo, Wenling Su, Yongsheng Gu, Xiaodan Qiu, Ting Zhao, Xiaofang Lian, Huiyi Liu, Qingying Jia, Ruifang Zheng and Guangzhi Shan
Separations 2025, 12(7), 168; https://doi.org/10.3390/separations12070168 - 25 Jun 2025
Viewed by 797
Abstract
Compound Glycyrrhizin tablets (CGTs) are a combination of glycyrrhizin, glycine and methionine. Glycine and methionine have relatively high polarity and lack chromophore; therefore, it is difficult to simultaneously determine the various components using traditional reversed-phase chromatography and ultraviolet detectors. In addition, it is [...] Read more.
Compound Glycyrrhizin tablets (CGTs) are a combination of glycyrrhizin, glycine and methionine. Glycine and methionine have relatively high polarity and lack chromophore; therefore, it is difficult to simultaneously determine the various components using traditional reversed-phase chromatography and ultraviolet detectors. In addition, it is even more challenging to obtain a comprehensive and systematic impurity profiling for the CGTs. In this study, an ion-pair high-performance liquid chromatography (HPLC)–charged aerosol detection (CAD) method was established to determine the content of glycyrrhizin, glycine and methionine. The impurities of CGTs were also identified using mass spectrometry. By optimizing the content of trifluoroacetic acid (TFA) in the mobile phase and optimizing the CAD parameter settings, the developed method was verified in accordance with the guidelines outlined in ICH Q2 (R2). The results indicated that the method demonstrated high accuracy and sensitivity. Glycine, methionine and glycyrrhizin all showed a good linear relationship within the labeled range of 50–200%, and the average recoveries of the three components were 97.62–100.6%. The impurity detection was quantified via the principal component control method. The limit of detection (LOD) method showed an equivalent to 0.05% of the glycyrrhizin in CGTs, approximately 12.5 ng. The ion-pair HPLC–CAD method developed in this study simultaneously determined the content of the main component and the impurities of CGTs, without necessitating derivatization. This has provided a research basis for further improving the quality standards of CGTs. Full article
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23 pages, 7244 KB  
Article
Electrospray–Mass Spectrometry-Guided Targeted Isolation of Indole Alkaloids from Leaves of Catharanthus roseus by Using High-Performance Countercurrent Chromatography
by Mahdi Yahyazadeh, Dirk Selmar and Gerold Jerz
Molecules 2025, 30(10), 2115; https://doi.org/10.3390/molecules30102115 - 9 May 2025
Viewed by 1043
Abstract
Electrospray mass spectrometry off-line profiling monitored the recovery of targeted indole alkaloids from a fortified crude extract of Catharanthus roseus (790 mg) using semi-preparative high-performance countercurrent chromatography (HPCCC) fractionation. Visualization of selected single-ion traces projected the HPCCC molecular weight elution profile. Experimental partition-ratio [...] Read more.
Electrospray mass spectrometry off-line profiling monitored the recovery of targeted indole alkaloids from a fortified crude extract of Catharanthus roseus (790 mg) using semi-preparative high-performance countercurrent chromatography (HPCCC) fractionation. Visualization of selected single-ion traces projected the HPCCC molecular weight elution profile. Experimental partition-ratio values KD and peak widths for detected metabolites were determined. Structural characterization of metabolites and co-elution effects were monitored in the scan range m/z 100–2000. In this study, the biphasic solvent system containing n-hexane–n-butanol–water with 0.5% ion-pair reagent trifluoro-acetic acid [1:1:2, v/v/v] was used based on partition ratio KD-value liquid chromatography–electrospray ionization–mass spectrometry (LC-ESI-MS) analysis prediction. The monitoring of target ions resulted in the isolation of six major concentrated indole alkaloids (akuammicine, catharanthine, perivine, vindoline, vindorosine, and 19R-vindolinine), which were fully elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Full article
(This article belongs to the Section Natural Products Chemistry)
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15 pages, 2419 KB  
Article
Complete Polar Lipid Profile of Kefir Beverage by Hydrophilic Interaction Liquid Chromatography with HRMS and Tandem Mass Spectrometry
by Giovanni Ventura, Mariachiara Bianco, Ilario Losito, Tommaso R. I. Cataldi and Cosima D. Calvano
Int. J. Mol. Sci. 2025, 26(3), 1120; https://doi.org/10.3390/ijms26031120 - 28 Jan 2025
Viewed by 1202
Abstract
Kefir, a fermented milk product produced using kefir grains, is a symbiotic consortium of bacteria and yeasts responsible for driving the fermentation process. In this study, an in-depth analysis of kefir’s lipid profile was conducted, with a focus on its phospholipid (PL) content, [...] Read more.
Kefir, a fermented milk product produced using kefir grains, is a symbiotic consortium of bacteria and yeasts responsible for driving the fermentation process. In this study, an in-depth analysis of kefir’s lipid profile was conducted, with a focus on its phospholipid (PL) content, employing liquid chromatography with high-resolution mass spectrometry (LC-HRMS). Nearly 300 distinct polar lipids were identified through hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray ionization (ESI) and Fourier-transform orbital-trap MS and linear ion-trap tandem MS/MS. The identified lipids included phosphatidylcholines (PCs), lyso-phosphatidylcholines (LPCs), phosphatidylethanolamines (PEs) and lyso-phosphatidylethanolamines (LPEs), phosphatidylserines (PSs), phosphatidylglycerols (PGs), and phosphatidylinositols (PIs). The presence of lysyl-phosphatidylglycerols (LyPGs) was identified as a key finding, marking a lipid class characteristic of Gram-positive bacterial membranes. This discovery highlights the role of viable bacteria in kefir and underscores its probiotic potential. The structural details of minor glycolipids (GLs) and glycosphingolipids (GSLs) were further elucidated, enriching the understanding of kefir’s lipid complexity. Fatty acyl (FA) composition was characterized using reversed-phase LC coupled with tandem MS. A mild epoxidation reaction with meta-chloroperoxybenzoic acid (m-CPBA) was performed to pinpoint double-bond positions in FAs. The dominant fatty acids were identified as C18:3, C18:2, C18:1, C18:0 (stearic acid), C16:0 (palmitic acid), and significant levels of C14:0 (myristic acid). Additionally, two isomers of FA 18:1 were distinguished: ∆9-cis (oleic acid) and ∆11-trans (vaccenic acid). These isomers were identified using diagnostic ion pairs, retention times, and accurate m/z values. This study provides an unprecedented level of detail on the lipid profile of kefir, shedding light on its complex composition and potential nutritional benefits. Full article
(This article belongs to the Collection Feature Papers Collection in Biochemistry)
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11 pages, 1914 KB  
Article
α-Olefin Oligomerization Mediated by Group 4 Metallocene Catalysts: An Extreme Manifestation of the Multisite Nature of Methylaluminoxane
by Francesco Zaccaria, Antonio Vittoria, Giuseppe Antinucci, Roberta Cipullo and Vincenzo Busico
Polymers 2025, 17(1), 46; https://doi.org/10.3390/polym17010046 - 28 Dec 2024
Cited by 2 | Viewed by 1711
Abstract
Group 4 metallocenes are competent catalysts for the oligomerization of higher α-olefins. Among the many chemical and physical variables of importance in the process, one is the choice of cocatalyst (activator). The impact of various activators on the performance of a representative catalyst, [...] Read more.
Group 4 metallocenes are competent catalysts for the oligomerization of higher α-olefins. Among the many chemical and physical variables of importance in the process, one is the choice of cocatalyst (activator). The impact of various activators on the performance of a representative catalyst, (nBuCp)2ZrCl2, in the oligomerization of 1-octene was thoroughly investigated; in particular, the molecular weight distribution (MWD) of the oligomers was determined by means of high-resolution high performance liquid chromatography (HR-HPLC). Unexpectedly, a bimodal MWD was highlighted when the precatalyst was activated with methylaluminoxane (MAO), whereas a single Schulz–Flory (SF) MWD was observed with borate salts. The presence of Al centers with different Lewis acidity in the complex and ill-defined structure of MAO is well known, and the broadening effects on the MWD of olefin polymerization products made with metallocene/MAO catalyst systems have been reported before. However, to the best of our knowledge, clear HR-HPLC evidence of two active species resulting from activation with MAO of one single zirconocene precursor, yielding two discrete SF product distributions, is unprecedented. By varying the polarity of the reaction medium, we managed to modulate the MWD of the oligomers from bimodal to monomodal, even with MAO, thus demonstrating that ion pairing effects are behind these unusual findings. Full article
(This article belongs to the Section Polymer Chemistry)
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25 pages, 3106 KB  
Article
Systematic Characterisation of the Fragmentation of Flavonoids Using High-Resolution Accurate Mass Electrospray Tandem Mass Spectrometry
by Candy Jiang and Paul J. Gates
Molecules 2024, 29(22), 5246; https://doi.org/10.3390/molecules29225246 - 6 Nov 2024
Cited by 9 | Viewed by 5647
Abstract
Flavonoids are a class of polyphenolic secondary metabolites found in plants. Due to their ubiquity in our daily dietary intake and their major anti-oxidative, anti-inflammatory and anti-mutagenic activities, they have been a major focus of wide-ranging research for the past two decades. Mass [...] Read more.
Flavonoids are a class of polyphenolic secondary metabolites found in plants. Due to their ubiquity in our daily dietary intake and their major anti-oxidative, anti-inflammatory and anti-mutagenic activities, they have been a major focus of wide-ranging research for the past two decades. Mass spectrometry combined with liquid chromatography is one of the most popular techniques for the analysis of flavonoids. In this study, high-resolution accurate mass electrospray tandem mass spectrometry was used to study 30 flavonoids in both positive and negative ionisation modes. From the data obtained, common losses were summarised and compiled. Dominating neutral losses were tabulated. The radical loss of CH3· was observed in flavonoids containing methoxy groups and three key diagnostic product ions were identified. These were m/z 153 (indicative of two OH groups on ring A) m/z 167 (indicative of one OH and one methoxy group on ring A) and m/z 151 (a flavanol, with no ketone oxygen but two OH groups on ring A). These will be useful in structural elucidation of unknown flavonoids and flavonoid metabolites. Energy breakdown graphs were utilised to distinguish between three pairs of structural isomers, and to help rationalise proposed fragmentation pathways. Lastly, a competition of loss of CH3· and methane was reported for rhamnetin and isorhamnetin in the negative ion mode for the first time. Proposed fragmentation pathways were given to rationalise the differences in peak intensities for this competitive process. Full article
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14 pages, 4663 KB  
Article
Core/Shell ZnO/TiO2, SiO2/TiO2, Al2O3/TiO2, and Al1.9Co0.1O3/TiO2 Nanoparticles for the Photodecomposition of Brilliant Blue E-4BA
by Mahboubeh Dolatyari, Mehdi Tahmasebi, Sudabeh Dolatyari, Ali Rostami, Armin Zarghami, Ashish Yadav and Axel Klein
Inorganics 2024, 12(11), 281; https://doi.org/10.3390/inorganics12110281 - 30 Oct 2024
Cited by 4 | Viewed by 2242
Abstract
The synthesis and characterization of ZnO/TiO2, SiO2/TiO2, Al2O3/TiO2, and Al1.9Co0.1O3/TiO2 core/shell nanoparticles (NPs) is reported. The NPs were used for photocatalytic degradation of brilliant [...] Read more.
The synthesis and characterization of ZnO/TiO2, SiO2/TiO2, Al2O3/TiO2, and Al1.9Co0.1O3/TiO2 core/shell nanoparticles (NPs) is reported. The NPs were used for photocatalytic degradation of brilliant blue E-4BA under UV and visible light irradiation, monitored by high-performance liquid chromatography and UV-vis absorption spectroscopy. The size of the NPs ranged from 10 to 30 nm for the core and an additional 3 nm for the TiO2 shell. Al2O3/TiO2 and Al1.9Co0.1O3/TiO2 showed superior degradation under UV and visible light compared to ZnO/TiO2 and SiO2/TiO2 with complete photodecomposition of 20 ppm dye in 20 min using a 10 mg/100 mL photocatalyst. The “Co-doped” Al1.9Co0.1O3/TiO2 NPs show the best performance under visible light irradiation, which is due to increased absorption in the visible range. DFT-calculated band structure calculations confirm the generation of additional electronic levels in the band gap of γ-Al2O3 through Co3+ ions. This indicates that Co-doping enhances the generation of electron–hole pairs after visible light irradiation. Full article
(This article belongs to the Special Issue New Advances into Nanostructured Oxides, 2nd Edition)
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13 pages, 2161 KB  
Article
Determination of Aminoglycosides by Ion-Pair Liquid Chromatography with UV Detection: Application to Pharmaceutical Formulations and Human Serum Samples
by Eliseo Herrero-Hernández, Diego García-Gómez, Irene Ramírez Pérez, Encarnación Rodríguez-Gonzalo and José Luis Pérez Pavón
Molecules 2024, 29(13), 3210; https://doi.org/10.3390/molecules29133210 - 5 Jul 2024
Viewed by 2075
Abstract
Aminoglycosides (AGs) represent a prominent class of antibiotics widely employed for the treatment of various bacterial infections. Their widespread use has led to the emergence of antibiotic-resistant strains of bacteria, highlighting the need for analytical methods that allow the simple and reliable determination [...] Read more.
Aminoglycosides (AGs) represent a prominent class of antibiotics widely employed for the treatment of various bacterial infections. Their widespread use has led to the emergence of antibiotic-resistant strains of bacteria, highlighting the need for analytical methods that allow the simple and reliable determination of these drugs in pharmaceutical formulations and biological samples. In this study, a simple, robust and easy-to-use analytical method for the simultaneous determination of five common aminoglycosides was developed with the aim to be widely applicable in routine laboratories. With this purpose, different approaches based on liquid chromatography with direct UV spectrophotometric detection methods were investigated: on the one hand, the use of stationary phases based on hydrophilic interactions (HILIC); on the other hand, the use of reversed-phases in the presence of an ion-pairing reagent (IP-LC). The results obtained by HILIC did not allow for an effective separation of aminoglycosides suitable for subsequent spectrophotometric UV detection. However, the use of IP-LC with a C18 stationary phase and a mobile phase based on tetraborate buffer at pH 9.0 in the presence of octanesulfonate, as an ion-pair reagent, provided adequate separation for all five aminoglycosides while facilitating the use of UV spectrophotometric detection. The method thus developed, IP-LC-UV, was optimized and applied to the quality control of pharmaceutical formulations with two or more aminoglycosides. Furthermore, it is demonstrated here that this methodology is also suitable for more complex matrices, such as serum, which expands its field of application to therapeutic drug monitoring, which is crucial for aminoglycosides, with a therapeutic index ca. 50%. Full article
(This article belongs to the Section Analytical Chemistry)
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10 pages, 6594 KB  
Communication
Tetrodotoxin Derivatization with a Newly Designed Boron Reagent Leads to Conventional Reversed-Phase Liquid Chromatography
by Shimba Kawasue, Kyoko Kuniyoshi, Masashi Uema and Naomasa Oshiro
Toxins 2024, 16(6), 260; https://doi.org/10.3390/toxins16060260 - 4 Jun 2024
Cited by 3 | Viewed by 2057
Abstract
Tetrodotoxin (TTX) is a representative natural toxin causing pufferfish food poisoning, which is especially prominent in East and Southeast Asia, including Japan. TTX has been analyzed through post-column derivatization high-performance liquid chromatography (HPLC), ion-pair LC-MS(/MS), and hydrophilic interaction liquid chromatography (HILIC)-MS(/MS) as alternatives [...] Read more.
Tetrodotoxin (TTX) is a representative natural toxin causing pufferfish food poisoning, which is especially prominent in East and Southeast Asia, including Japan. TTX has been analyzed through post-column derivatization high-performance liquid chromatography (HPLC), ion-pair LC-MS(/MS), and hydrophilic interaction liquid chromatography (HILIC)-MS(/MS) as alternatives to the mouse bioassay method. However, post-column derivatization requires a system for online derivatization reactions, and with the ion-pair LC-MS approach, it is difficult to remove residual ion-pair reagents remaining in the equipment. Moreover, HILIC-MS provides poor separation compared to reversed-phase (RP) HPLC and requires a long time to reach equilibration. Therefore, we decided to develop a TTX analytical method using pre-column derivatization and RP HPLC for the rapid assessment of outbreak samples, including food remnants. In this study, we focused on the vic-diol moiety of TTX and designed a new derivatization reagent coded as NBD-H-DAB. This NBD-H-DAB was synthesized from 4-hydrazino-7-nitro-2,1,3-benzoxadiazole (NBD-H) and 3-fluoro-2-formylphenylboronic acid (FFPBA) with a simple reaction system and rapidly converted to its boronate form, coded NBD-H-PBA, in an aqueous reaction solution. The NBD-H-PBA demonstrated appropriate hydrophobicity to be retained on the RP analytical column and successfully detected with a UV spectrometer. It was easily reacted with the vic-diol moiety of TTX (C6 and C11) to synthesized a boronic ester. The derivatized TTX could be detected using the RP HPLC-UV, and the limit of detection in the fish flesh samples was 0.06 mg/kg. This novel pre-column derivatization of TTX with NBD-H-PBA proves capable for the analysis of TTX. Full article
(This article belongs to the Special Issue Analytical Chemistry Techniques in Toxin Detection)
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12 pages, 1596 KB  
Article
Unveiling Novel Chaotropic Chromatography Method for Determination of Pralidoxime in Nerve Agent Antidote Autoinjectors
by Bohyun Shin, Hyung-seung Kim, Ji-Youn Lee, Sumin Seo, Cho Hee Jeong, Eunbin Bae, Jiyu Kim, Hyojeong Lee, Donghee Lee, Dong-Kyu Lee and Sang Beom Han
Separations 2024, 11(3), 82; https://doi.org/10.3390/separations11030082 - 7 Mar 2024
Viewed by 2885
Abstract
Pralidoxime chloride, a highly hydrophilic antidote, cannot be effectively separated by reverse-phase high-performance liquid chromatography (RP-HPLC), unless the mobile-phase composition is varied. However, the use of ion-pairing reagents for pralidoxime separation is hindered by the persistent contamination of the stationary phase or chromatography [...] Read more.
Pralidoxime chloride, a highly hydrophilic antidote, cannot be effectively separated by reverse-phase high-performance liquid chromatography (RP-HPLC), unless the mobile-phase composition is varied. However, the use of ion-pairing reagents for pralidoxime separation is hindered by the persistent contamination of the stationary phase or chromatography system inside the HPLC system. Thus, this study aimed to develop a simple, rapid, and robust method based on RP-HPLC to determine pralidoxime chloride in antidote autoinjectors using a chaotropic salt as the mobile-phase additive. The use of UV detection at 270 nm allowed for the simultaneous detection of pralidoxime chloride and the internal standard, pyridine-2-aldoxime. The addition of chaotropic salts (NaPF6, NaBF4, and NaClO4) and an ionic liquid ([EMIM]PF6) increased the retention time of pralidoxime chloride. Among them, NaPF6 exhibited the highest capacity factor in the reverse-phase C18 column. Increasing the salt concentration increased the capacity factor and the number of theoretical plates. Analytical method validation was performed to assess the linearity, accuracy, precision, recovery, and repeatability, according to the Ministry of Food and Drug Safety guidelines. Additionally, this newly developed method exhibits an adequate separation capability, making it a potential substitute for the current method employed in the United States/Korean Pharmacopoeia, and it ensures the necessary durability to maintain the robustness and reliability of the analytical system. Full article
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16 pages, 1634 KB  
Article
Development of a Novel Bronchodilator Vaping Drug Delivery System Based on Thermal Degradation Properties
by Mariam Chaoui, Emmanuelle Fischer, Sophie Perinel-Ragey, Nathalie Prévôt, Lara Leclerc and Jérémie Pourchez
Pharmaceuticals 2023, 16(12), 1730; https://doi.org/10.3390/ph16121730 - 15 Dec 2023
Cited by 2 | Viewed by 2801
Abstract
This work aims to investigate bronchodilator delivery with the use of different vaping drug delivery systems (VDDS) by determining the dose equivalence delivered in relation to different references: a clinical jet nebulizer, a pMDI (pressurized metered dose inhaler) and a DPI (dry powder [...] Read more.
This work aims to investigate bronchodilator delivery with the use of different vaping drug delivery systems (VDDS) by determining the dose equivalence delivered in relation to different references: a clinical jet nebulizer, a pMDI (pressurized metered dose inhaler) and a DPI (dry powder inhaler). Three different bronchodilators were used (terbutaline, salbutamol hemisulfate, ipratropium bromide). The e-liquids contained the active pharmaceutical ingredient (API) in powder form. Two different VDDS were tested (JUUL and a GS AIR 2 atomizer paired with a variable lithium-ion battery (i-stick TC 40 W), 1.5 ohm resistance, and 15 W power). Samples were collected using a glass twin impinger (GTI). High-performance liquid chromatography (HPLC) was used to quantify the drugs. A next-generation impactor (NGI) was used to measure the particle size distribution. Terbutaline emerged as the optimal API for bronchodilator delivery in both VDDS devices. It achieved the delivery of a respirable dose of 20.05 ± 4.2 µg/puff for GS AIR 2 and 2.98 ± 0.52 µg/puff for JUUL. With these delivered doses, it is possible to achieve a dose equivalence similar to that of a jet nebulizer and DPI, all while maintaining a reasonable duration, particularly with the GS AIR 2. This study is the first to provide evidence that vaping bronchodilators work only with appropriate formulation, vaping technology, and specific drugs, depending on their thermal degradation properties. Full article
(This article belongs to the Section Pharmaceutical Technology)
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20 pages, 2638 KB  
Article
Unveiling the Protein Components of the Secretory-Venom Gland and Venom of the Scorpion Centruroides possanii (Buthidae) through Omic Technologies
by Patricia Elizabeth García-Villalvazo, Juana María Jiménez-Vargas, Gisela Jareth Lino-López, Erika Patricia Meneses, Manuel de Jesús Bermúdez-Guzmán, Carlos Eduardo Barajas-Saucedo, Iván Delgado Enciso, Lourival Domingos Possani and Laura Leticia Valdez-Velazquez
Toxins 2023, 15(8), 498; https://doi.org/10.3390/toxins15080498 - 9 Aug 2023
Cited by 11 | Viewed by 3120
Abstract
Centruroides possanii is a recently discovered species of “striped scorpion” found in Mexico. Certain species of Centruroides are known to be toxic to mammals, leading to numerous cases of human intoxications in the country. Venom components are thought to possess therapeutic potential and/or [...] Read more.
Centruroides possanii is a recently discovered species of “striped scorpion” found in Mexico. Certain species of Centruroides are known to be toxic to mammals, leading to numerous cases of human intoxications in the country. Venom components are thought to possess therapeutic potential and/or biotechnological applications. Hence, obtaining and analyzing the secretory gland transcriptome and venom proteome of C. possanii is relevant, and that is what is described in this communication. Since this is a newly described species, first, its LD50 to mice was determined and estimated to be 659 ng/g mouse weight. Using RNA extracted from this species and preparing their corresponding cDNA fragments, a transcriptome analysis was obtained on a Genome Analyzer (Illumina) using the 76-base pair-end sequencing protocol. Via high-throughput sequencing, 19,158,736 reads were obtained and ensembled in 835,204 sequences. Of them, 28,399 transcripts were annotated with Pfam. A total of 244 complete transcripts were identified in the transcriptome of C. possanii. Of these, 109 sequences showed identity to toxins that act on ion channels, 47 enzymes, 17 protease inhibitors (PINs), 11 defense peptides (HDPs), and 60 in other components. In addition, a sample of the soluble venom obtained from this scorpion was analyzed using an Orbitrap Velos apparatus, which allowed for identification by liquid chromatography followed by mass spectrometry (LC-MS/MS) of 70 peptides and proteins: 23 toxins, 27 enzymes, 6 PINs, 3 HDPs, and 11 other components. Until now, this work has the highest number of scorpion venom components identified through omics technologies. The main novel findings described here were analyzed in comparison with the known data from the literature, and this process permitted some new insights in this field. Full article
(This article belongs to the Special Issue Animal Venoms: Proteomics, Biochemical Activities and Application)
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11 pages, 1324 KB  
Article
New Green and Sustainable Tool for Assessing Nitrite and Nitrate Amounts in a Variety of Environmental Waters
by H. R. Robles-Jimarez, N. Jornet-Martínez and P. Campíns-Falcó
Water 2023, 15(5), 945; https://doi.org/10.3390/w15050945 - 1 Mar 2023
Cited by 4 | Viewed by 2921
Abstract
This paper aims to provide improved selectivity and sensitivity with a short analysis time of about 10 min and low residues for quantitation of nitrite and nitrate in waters by liquid chromatography. Ion-pair formation and ion exchange retention mechanisms were considered. The optimized [...] Read more.
This paper aims to provide improved selectivity and sensitivity with a short analysis time of about 10 min and low residues for quantitation of nitrite and nitrate in waters by liquid chromatography. Ion-pair formation and ion exchange retention mechanisms were considered. The optimized option was in-tube solid phase microextraction (IT-SPME) by means of a silica capillary of 14 cm length and 0.32 mm id, coupled online with a capillary anion exchange analytical column (Inertsil AX 150 × 0.5 mm id, 5 µm) and the use of their native absorbance. Precision of the retention times expressed as % relative standard deviation (RSD) were <1% for both, nitrite (tR = 5.8 min) and nitrate (tR = 10.5 min). Well, river, channel, lake, sea, tap and bottled waters and several matrices of a drinking water treatment plant were analysed, and no matrix effect was observed for all of them. Inorganic anions and several organic acids were tested as possible interferences and suitable selectivity was obtained. Precision expressed as % relative standard deviation (RSD) was between 0.9 and 3%. Low detection limits of 0.9 and 9 μg/L for nitrite and nitrate were obtained, respectively, and low residue generation near 100 µL per run was also achieved. Full article
(This article belongs to the Special Issue Water Environment Pollution and Control)
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25 pages, 5028 KB  
Article
Development and Validation of an LC-MS/MS Method for the Quantitative Determination of Contezolid in Human Plasma and Cerebrospinal Fluid
by Guanxuanzi Zhang, Na Zhang, Liuhan Dong, Nan Bai and Yun Cai
Pharmaceuticals 2023, 16(1), 32; https://doi.org/10.3390/ph16010032 - 26 Dec 2022
Cited by 6 | Viewed by 3236
Abstract
To develop and verify a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining contezolid in plasma and cerebrospinal fluid (CSF). Protein precipitation was performed on samples using linezolid as the internal standard. We used an Agilent EclipsePlus C18 column operating at 0.4 mL/min [...] Read more.
To develop and verify a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining contezolid in plasma and cerebrospinal fluid (CSF). Protein precipitation was performed on samples using linezolid as the internal standard. We used an Agilent EclipsePlus C18 column operating at 0.4 mL/min in conjunction with acetonitrile and water mobile phases for the LC-MS/MS analysis. Using the precursor-product ion pairs 409.15→269.14 (contezolid) and 338.14→195.1 (linezolid), multiple reaction monitoring was used to quantify the compounds. Plasma linearity range was 50.0 to 5000 ng/mL, and CSF was 20.0 to 1000 ng/mL (r2 = 0.999). The inter-batch and intra-batch precisions were ≤2.57% and ≤5.79%, respectively. Plasma recovered 92.94%, and CSF recovered 97.83%. Plasma, CSF, hemolytic plasma, and hyperlipidemic plasma all showed a coefficient of variation ≤ 7.44%. The stability and dilution integrity of this method were also acceptable. The study also demonstrated that artificial CSF can be used as a matrix for the preparation of standard curve samples. A simple and accurate method was developed and validated for the determination of contezolid concentrations in human plasma and CSF, which may be useful for monitoring the therapeutic effect of central nervous system medications. Full article
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19 pages, 1614 KB  
Article
Cholesterol Stationary Phase in the Separation and Identification of siRNA Impurities by Two-Dimensional Liquid Chromatography-Mass Spectrometry
by Sylwia Studzińska, Feiyang Li, Michał Szumski, Bogusław Buszewski and Michael Lämmerhofer
Int. J. Mol. Sci. 2022, 23(23), 14960; https://doi.org/10.3390/ijms232314960 - 29 Nov 2022
Cited by 10 | Viewed by 2805
Abstract
The aim of this research was to develop a simple and efficient ion-pair reagent-free chromatographic method for the separation and qualitative determination of oligonucleotide impurities, exemplified by synthesis of raw products of the two single strands of patisiran siRNA. The stationary phases with [...] Read more.
The aim of this research was to develop a simple and efficient ion-pair reagent-free chromatographic method for the separation and qualitative determination of oligonucleotide impurities, exemplified by synthesis of raw products of the two single strands of patisiran siRNA. The stationary phases with mixed hydrophobic/hydrophilic properties (cholesterol and alkylamide) were firstly used for this purpose with reversed-phased high-performance liquid chromatography. Several different chromatographic parameters were tested for their impact on impurities separation: type, concentration, pH of salt, as well as organic solvent type in the mobile phase. The pH was the most influential factor on the separation and signal intensities in mass spectrometry detection. Finally, the optimized method included the application of cholesterol stationary phase, with mobile phase containing 20 mM ammonium formate (pH 6.5) and methanol. It allowed good separation and the identification of most impurities within 25 min. Since not all closely related impurities could be fully resolved from the main peak in this oligonucleotide impurity profiling, two-dimensional liquid chromatography was used for peak purity determination of the target oligonucleotides. The Ethylene Bridged Hybrid (BEH) Amide column in hydrophilic interaction liquid chromatography was applied in the second dimension, allowing additional separation of three closely related impurities. Full article
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