Electrospray Ionization Source Research Articles

Stereoselectivity of evodiamine enantiomers in neuroprotective activity, pharmacokinetics and the ability across the blood-brain barrier.

Evodiamine, a chiral quinazoline alkaloid in the traditional Chinese medicine Evodiae fructus, exhibited efficacy for CNS diseases. In this study, the pure enantiomers of evodiamine were prepared in large quantities via chemical resolution. Their structures were elucidated by MS, NMR and ECD. The optical purity was determined to be as high as 99.8 %. The differences of the enantiomers in protective effect against neuronal cell injury were evaluated using MTT assay. Notably, R-(-)-evodiamine showed better neuroprotection effects against H2O2-induced damage in PC12 cells. An efficient HPLC-MS/MS method for determination of evodiamine enantiomers in rat plasma and brain was developed and verified. Satisfactory enantioseparation of evodiamine was achieved on a Chiralcel OD-RH column with the mobile phase of acetonitrile-water (70:30, v/v) at a flow rate of 0.6 mL/min. The analytes were measured under multiple reactions monitoring (MRM) mode with m/z 304.3→134.3 for evodiamine and m/z 289.3→97.1 for testosterone (IS) using electrospray ionization source (ESI) in the positive ion mode. The method was validated and fulfilled the requirements of bioanalysis. It was successfully applied to study the stereoselectivity of evodiamine in pharmacokinetics and the ability across the blood-brain barrier in rats. After oral and intravenous administration of racemic evodiamine to rat, the area under the concentration-time curve of R-evodiamine was noticeably 1.70 and 1.33 times higher than those of S-evodiamine, respectively. Furthermore, while there was no significant difference in the B/P values, the concentration of R-(-)-evodiamine in the brain was approximately 1.31 times greater than that of S-(+)-evodiamine. The results indicated that evodiamine enantiomers exhibited significant stereoselectivity in pharmacokinetics after oral administration and intravenous administration. While the two enantiomers showed no significant stereoselectivity in the ability across the blood-brain barrier. These findings provided new insights into the development of a single enantiomer of evodiamine as a potential drug candidate for the treatment of CNS diseases.

Determination of glufosinate, glyphosate and their metabolites in sediment by ultra-high performance liquid chromatography-tandem mass spectrometry with pass-through solid-phase extraction

Glufosinate (GLUF) and glyphosate (GLY) are nonselective phosphorus-containing amino acid herbicides that are widely used in agricultural gardens and noncultivated areas. These herbicides give rise to a number of key metabolites, with 3-methyl phosphinicopropionic acid (MPPA), N-acetyl glufosinate (N-acetyl GLUF), aminomethyl phosphonic acid (AMPA), N-acetyl aminomethyl phosphonic acid (N-acetyl AMPA), N-acetyl glyphosate (N-acetyl GLY), N-methyl glyphosate (N-methyl GLY) as the major metabolites obtained from GLUF and GLY. Extensive use of these herbicides may lead to their increased presence in the environment, especially aquatic ecosystems. An increasing number of research studies into the toxicities of GLUF, GLY, and their metabolites have shown that these herbicides are potentially toxic to aquatic biota. GLUF and GLY, as well as their metabolites, are extremely polar and water-soluble, and they lack chromogenic and fluorescent groups; therefore, their concentrations are difficult to determine using conventional methods. Most analytical methods used to date have largely depended on derivatization procedures, leading to overall determination processes that are tedious and time-consuming. Therefore, establishing a quick and sensitive method that does not require derivatives for determining GLUF, GLY, and their metabolites in water environments, including surface water, sediments, and aquatic organisms, is an important endeavor. In this study, a new approach was developed based on pass-through solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to determine GLUF, GLY, and their metabolites, including MPPA, N-acetyl GLUF, AMPA, N-acetyl AMPA, N-acetyl GLY, and N-methyl GLY, in sediments. Samples were extracted with 4% (v/v) ammonia water and purified using PRiME HLB pass-through solid-phase extraction columns. The extracts were filtered through a polyethersulfone microfiltration membrane and analyzed by UHPLC-MS/MS. Compounds were separated on a Metrosep A Supp 5 column (150 mm×4.0 mm, 5 μm) using gradient elution with water and 200 mmol/L ammonium hydrogen carbonate solution containing 0.05% (v/v) ammonia water as the mobile phases. Analytes were detected using MS/MS with a negative electrospray ionization (ESI-) source in the multiple reaction monitoring (MRM) mode. A matrix-matched external-standard approach was used for quantitative analysis. GLUF, GLY, and their metabolites were detected within 15 min with good peak shapes and high responses. Calibration curves were linear in the range of 2.0-200 μg/L, with correlation coefficients exceeding 0.995. This method delivered limits of detection (LODs) and limits of quantification (LOQs) of 5 μg/kg and 20 μg/kg, respectively, for GLUF, MPPA, N-acetyl-GLUF, N-acetyl AMPA, N-acetyl GLY, and N-methyl GLY, and 10 μg/kg and 30 μg/kg, for GLY and AMPA, respectively. Average spiked recoveries at three levels (LOQ, 5LOQ, 10LOQ) in sediment with low organic matter content were in the range of 78.5%-107%, and the relative standard deviations (RSDs) were in the range of 1.32%-14.7% (n=6). Average spiked recoveries of 76.4%-113% were determined for three levels (LOQ, 5LOQ, and 10LOQ) in sediments with high organic matter contents, with RSDs of 2.60%-11.2% (n=6). The developed method was used to analyze GLUF, GLY, and their metabolites in ponds, lakes, reservoirs, and river sediments. No target compounds were detected in any sediment sample obtained from a lake, reservoir, or river; however, GLY and AMPA were detected in one pond-sediment sample at levels of 31.7 and 52.3 μg/kg, respectively. The developed approach is simple, fast, and green; moreover, it offers advantages, including high accuracies, high sensitivities, and good reproducibilities. Accordingly, the developed method is suitable for determining GLUF, GLY, and their metabolites in sediments and can provide technical support for studying residue characteristics and environmental behavior in sediments.

High resolving power electrospray drift tube ion mobility spectrometer with heated desolvation tube.

The separation performance of drift tube ion mobility spectrometers is usually relatively weak with resolving powers well below 100. Improving this aspect requires, besides the optimization of other parameters, the challenging increase of the drift voltage as deduced from fundamental equations describing the broadening of a drifting ion swarm. We recently succeeded in constructing an improved high voltage instrument equipped with an electrospray source capable of analysing liquid samples with resolving powers above 200. This instrument was further perfected with a newly developed heated desolvation tube guiding the ions to the injection gate. The electrospray desolvation process was thus enhanced while the separation region was maintained at room temperature to keep diffusional band broadening to a minimum. A further modification was also made to the detector circuitry in order to reduce its noise. To demonstrate the performance of the instrument several challenging ion mixtures, including two herbicides, a polymer mixture, and isomers of carnitine esters were successfully separated and detected. The resolving powers, calculated from the arrival time and peak width at half height, ranged from 123 to 228. The latter value represents 96% of the theoretically achievable resolving power at the working drift voltage of 24.1kV. Stand-alone electrospray ion mobility spectrometry is not often used and has not yet been developed to its full potential. The results with improved resolving powers demonstrate its capability as a simple technique for the analysis of liquid samples, which may often serve as a lower cost alternative to chromatography or mass spectrometry.

Thermometer Ions, Internal Energies, and In-Source Fragmentation in Ambient Ionization.

Ionization and fragmentation are at the core of mass spectrometry. But they are not necessarily separated in space, as in-source fragmentation can also occur. Here, we survey the literature published since our 2005 review on the internal energy and fragmentation in electrospray ionization sources. We present new thermometer molecules to diagnose and quantify source heating, provide tables of recommended threshold (E0) and appearance energies (Eapp) for the survival yield method, and attempt to compare the softness of a variety of ambient pressure ionization sources. The droplet size distribution and desolvation dynamics play a major role: lower average internal energies are obtained when the ions remain protected by a solvation shell and spend less time nakedly exposed to activating conditions in the transfer interface. Methods based on small droplet formation without charging can thus be softer than electrospray. New dielectric barrier discharge sources can gas-phase ionize small molecules while conferring barely more internal energy than electrospray ionization. However, the tuning of the entire source interface often has an even greater influence on ion internal energies and fragmentation than on the ionization process itself. We hope that this review will facilitate further research to control and standardize in-source ion activation conditions, and to ensure the transferability of data and research results in mass spectrometry.

Suppression of Collision-Induced Dissociation in a Supersonically Expanding Gas.

In high-resolution mass spectrometry, an electrospray ionization source is often paired with an ion-funnel to enhance ion transmission. Although it is established that ions experience collision-induced dissociation as they pass through this device, the impact of gas-flow dynamics on ion fragmentation remains unexplored. The present work demonstrates that the gas-flow dynamics from the capillary interface of an electrospray ionization source into an ion-funnel significantly reduces ion fragmentation. This reduction stems from the substantial decrease in the rate of increase in the internal energy of the ions, resulting from the collisions with a supersonically expanding gas. The results of this study have significant consequences for systems that employ electrospray mass spectrometry and ion-mobility spectrometry as well as in interdisciplinary fields involving ion transport through a gaseous medium.

Characterization of a single emitter passively fed electrospray ion source: part I - luminescence imaging analysis

Abstract Luminescence at the face of ionic liquid ion sources and nearby facility surfaces is a commonly reported radiative phenomenon that requires thorough examination. In this study, we present magnified images of a single emitter porous-media ionic liquid electrospray in profile, which provides spatial information on the origin of the luminescence. To determine what role facility interactions play in luminescence at the electrospray face, we varied the distance and material of a downstream beam target on which the ion plume terminated. The effect of applied emitter voltage on luminescence was also examined. Analysis of luminescence images and corresponding telemetry data demonstrate that the formation of luminescence near the emitter tip is not only a function of the surrounding test facility, but also dependent on the electrospray device, itself. The data also indicate the majority of luminescence observed within our experimental system is formed primarily from high-energy collisions between emitted propellant ions and propellant accumulated on the orifice of the extractor electrode.

Characterization of a single emitter passively fed electrospray ion source: part II-luminescence spectral analysis

Abstract Luminescence spectroscopy was used to examine the dynamics of propellant dissociation near the emitter tip of a single-emitter porous electrospray thruster loaded with the ionic liquid EMI-BF4. Luminescence spectra from CH, C2, CN, NH, BH, Hα, and Hβ were observed and confirmed by comparison with simulated spectra. Analysis of the CH (A 2Δ, v’ = 0) spectra yielded a rotational temperature 3082±30 K while the C2 (d 3Πg – a 3Πu) Swan system yielded rotational temperatures 6252±92 K and 5914±75 K for Δv = 0 and Δv = +1, respectively. Examination of the integrated spectral signals from acquired CH (A 2Δ), BH (A 1Π), and Hα spectra showed a strong correlation with measured extractor current in both positive and negative polarity mode. The evidence suggests the formation of these electronically excited species is due to dissociative excitation induced by high-energy collisions between emitted ions and propellant accumulated on the extractor orifice. A weak broadband signal was also observed and is likely due to dissociative excitation of the anion, BF4 -, leading to the formation of electronically excited BF2. Analysis of the neutral gas within the test chamber with a mass spectrometer confirmed the presence of BF2, providing strong evidence the observed broadband signal is the result of BF2.

Quasi-Simultaneous Identification of Polar and Neutral Lipids in Mass Spectrometry by kHz Switching of Electrospray and Plasma Ionization.

The identification of polar and neutral lipid species as biomarkers in complex biological samples is a key task in clinical and life sciences. Electrospray and plasma-based ionization techniques are necessary to cover the full range of lipidomes, owing to their limited molecular polarity ranges. However, combining both to generate hybrid spectra is difficult without averaging spectra, as electrospray and plasma sources operate under vastly different conditions. Their electric fields also interfere, resulting in a mutual destabilization of the ionization processes. Herein, a heated nanoelectrospray is combined with a flexible microtube plasma using a rapid (kHz range) switching process (heated nESI-sFμTP) to generate quasi-simultaneous ionization. This approach loads the ion trap with polar and less-polar ions during each injection cycle, generating hybrid spectra without averaging it. The performance of the quasi-simultaneous approach is investigated in positive ion mode, comparing it with conventional ion sources through the analysis of complex lipid liver and heart samples. While no improvements are observed in negative ion mode, the novel quasi-simultaneous approach shows great potential for analyzing complex samples in positive ion mode. The combined heated nESI-sFμTP exceeds the molecular polarity range of individual sources, offering excellent ionization efficiency and MS2 capabilities.

An Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry Method for the Determination of Deoxycholic Acid and Application to a Pharmacokinetic Study in Human Plasma.

Deoxycholic acid (DCA) injection is applied in treating moderate to severe submental bulge or facial fullness caused by excessive submental fat accumulation. Using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technology, which was swiftly, precisely, and reliably confirmed, DCA was determined in human plasma with low quantification limits of 56 ng/mL. We selected six healthy individual blank human plasma with low concentrations of endogenous DCA and mixed them to prepare standard curve samples. The samples were purified by the protein precipitation technique and then separated using a BEH C18 column (2.1 × 50 mm, 1.7 μm). Using multiple reaction monitoring (MRM) and electrospray ionization (ESI) sources operating in negative mode, the mass was identified and measured. The precursor-to-product ion transitions were observed at m/z 391.2- → 345.2- and m/z 395.2- → 349.2- for DCA and DCA-d4 (isotope internal standard), respectively. This method was thoroughly validated, encompassing assessments of linearity, sensitivity, precision, selectivity, stability, matrix effect, accuracy, carryover, and recovery. In a word, the validation results demonstrated that this method exhibited sensitivity, accuracy, and reproducibility and could effectively be utilized for studying the pharmacokinetic properties of DCA in a randomized, parallel, controlled, Phase I clinical trial.

Solid-phase extraction coupled with high performance liquid chromatography-triple quadrupole mass spectrometry for simultaneous determination of seven coumarins in water samples from drinking water treatment plants

Chlorinated coumarins, which are as cytotoxic as highly toxic halobenzoquinones toward CHO-K1 cells, have recently been identified as disinfection byproducts in drinking water disinfection processes. Therefore, detecting coumarins in water samples collected at various stages from drinking water treatment plants helps assess the formation of chlorinated coumarins in drinking water. Hence, a simple, rapid, accurate, and sensitive method for quantifying coumarins in water samples is required. In this study, a method was developed based on solid-phase extraction coupled with high performance liquid chromatography-triple-quadrupole mass spectrometry for analyzing seven coumarins in water samples from drinking water treatment plants, including 6,7-dihydroxycoumarin, 7-hydroxycoumarin, 6-hydroxy-4-methylcoumarin, 8-chloro-7-hydroxycoumarin, coumarin, 7-chloro-6-hydroxy-4-methylcoumarin, and 3,8-dichloro-7-hydroxycoumarin. Sample pretreatment involved solid-phase extraction using HLB columns, followed by elution with water and methanol, each containing 0.25% formic acid. The extracted solution was separated via gradient elution using a Phenomenex Luna C18 column (100 mm×2.0 mm, 3 mm) with 0.1% formic acid aqueous solution and methanol as the mobile phases, with analytes detected by triple-quadrupole mass spectrometry equipped with electrospray ionization source in multiple reaction monitoring mode. The matrix effect, precision, and accuracy of the developed method were investigated using raw and treated water as matrices. Matrix effects of 0.84-1.12 were recorded for the detection of 6,7-dihydroxycoumarin, 7-hydroxycoumarin, 6-hydroxy-4-methylcoumarin, and coumarin in raw water, while values of 0.67-0.70 were recorded for 8-chloro-7-hydroxycoumarin, 7-chloro-6-hydroxy-4-methylcoumarin, and 3,8-dichloro-7-hydroxycoumarin in finished water. The three chlorinated coumarins exhibited matrix effects above 0.80 after the finished water matrix had been diluted four times. These results suggest that only simple solid-phase extraction or sample dilution is required to accurately determine the seven coumarins in drinking water from treatment plants. In addition, these coumarins exhibited good linear relationships at their respective mass concentrations. The precision and accuracy of the method were evaluated using raw and treated water as matrices. The seven coumarins exhibited good linearities by triple-quadrupole mass spectrometry in a certain range, with correlation coefficients (r) greater than 0.99 and method detection limits (MDLs) of 0.67-1.12 ng/L. The seven coumarins exhibited recoveries of 61.4%-91.5% at three spiked levels (20, 50, 100 ng/L) with relative standard deviations (RSDs, n=6)≤11.2%. The developed method can be used to analyze water samples from various treatment stages of a drinking-water treatment plant. 7-Hydroxycoumarin, 6,7-dihydroxycoumarin, and coumarin were detected at levels of 0.21-27.9 ng/L in 100% of the samples, while 6-hydroxy-4-methylcoumarin was not detected in raw water, post-coagulated water, and post-carbon-filtered water, but was found in sand-filtered water and finished water, with higher levels recorded for the latter (4.69 ng/L) than the former (1.79 ng/L). 8-Chloro-7-hydroxycoumarin was only detected in treated water (0.07 ng/L). This method is highly precise and accurate, provides results in short analysis times, and can be used to effectively monitor coumarins in real water samples and assess their removal during drinking-water treatment.

Quantification of crisugabalin (HSK16149) in biological matrix by LC-MS/MS method: An application to rat pharmacokinetic and tissue distribution studies

Crisugabalin (HSK16149), a novel VGCC α2δ ligand, has been approved for the treatment of adult diabetic peripheral neuropathic pain (DPNP) and postherpetic neuralgia (PHN). In this study, an LC-MS/MS method was developed for the determination of crisugabalin in rat plasma and tissues homogenate. Samples were extracted by protein precipitation and separated on a Hypersil GOLD aQ column with methanol and 2mM ammonium acetate in water containing 0.1% formic acid as mobile phase. Crisugabalin and its internal standard HSK7891 were ionized by electrospray ionization source and detected by multiple reaction monitoring with transitions of m/z 210.9→134.4 and m/z 246.0→129.3. Over the range of 0.0100-10.0μg/mL, the selectivity, linearity, precision and accuracy, matrix effect, stability, recovery and dilution integrity of crisugabalin were validated in rat plasma. Validation was also performed in rat liver homogenate at concentrations ranging from 0.0200-20.0μg/g. The method was then successfully applied to determine the pharmacokinetics and tissue distribution of crisugabalin. In rats, orally administered crisugabalin was completely and rapidly absorbed with a peak time of about 0.57h, and was mainly distributed to kidney, bladder and liver tissues. Crisugabalin exhibited linear pharmacokinetics over the oral dose range of 3-30mg/kg.

Comprehensive Quality Evaluation of Traditional Chinese Medicine Guanxinjing Capsule Based on Fingerprint and Multicomponent Simultaneous Quantitative Method.

A novel dual-wavelength ultrahigh performance liquid chromatography (UHPLC) fingerprint was established, 56 common peaks were confirmed and attributed to the source of the medicinal materials, and 13 chromatographic peaks of them were identified by UHPLC quadrupole time-of-flight (Q-TOF)-MS/MS and UHPLC-UV method. Furthermore, a simple and sensitive HPLC-quadrupole trap (Q-TRAP)-MS/MS was developed for the simultaneous determination of 16 active components with electrospray ionization (ESI) source switching between positive and negative modes in a single run. The above two methods were successfully applied for the quality evaluation of Guanxinjing capsule (GXJC). Finally, statistical analysis including principal component analysis (PCA), hierarchical cluster analysis (HCA), and orthogonal partial least squares discriminate analysis (OPLS-DA) were applied, and 13 variables with great contribution to different groups of samples were screened. This study not only provides a rapid, accurate, and comprehensive qualitative and quantitative method for quality evaluation of GXJC but it also provides a reference workflow for the other traditional Chinese medicines.

Fluorescent nanodiamond scintillators for beam diagnostics of EUV and soft X-ray in photolithographic applications.

Extreme ultraviolet (EUV) lithography is a cutting-edge technology in contemporary semiconductor chip manufacturing. Monitoring the EUV beam profiles is critical to ensuring consistent quality and precision in the manufacturing process. This study uncovers the practical use of fluorescent nanodiamonds (FNDs) coated on optical image sensors for profiling EUV and soft X-ray (SXR) radiation beams. We employed a positive electrospray ion source to deposit 100 nm FNDs onto indium tin oxide (ITO)-coated substrates, forming 1 μm thick films. The scintillation films exhibited approximately 50% transparency in the visible region and could emit red fluorescence from neutral nitrogen-vacancy (NV0) centers in the FNDs when exposed to EUV/SXR radiation. We evaluated the performance of a device featuring an FND coating on a fiber optic plate (FOP) attached to the sensor of a complementary metal-oxide semiconductor (CMOS) camera using synchrotron radiation across the 80-1400 eV energy range. At 91.8 eV (or a wavelength of 13.5 nm), the fiber-coupled device exhibited a noise-equivalent power density of 0.25 μW cm-2 Hz-1/2, approximately eight times lower than that of an f/1.0 lens-coupled system. This enhanced sensitivity makes the FND/FOP-based detection system useful for beam profiling of various EUV/SXR radiation sources. Our results highlight the promising potential of electrosprayed FND scintillators as a cost-effective and versatile diagnostic tool for advancing next-generation photolithography.

Flow Injection Analysis–Mass Spectrometry for the fast detection of frauds in Coleus forskohlii food supplements

Flow Injection Analysis–Mass Spectrometry for the fast detection of frauds in Coleus forskohlii food supplements

Determination of 12 halogenated organic pollutants in edible fish by ultra performance liquid chromatography-high resolution mass spectrometry combined with ultrasound-assisted extraction and gel permeation chromatography purification

Halogenated organic pollutants (HOPs) have attracted considerable attention owing to their persistence, bioaccumulation, and toxicity. The development of methods to detect HOPs in fish is challenging owing to the compositional complexity of fish matrices, which contain high levels of lipids and relatively low concentrations of HOPs. In addition, the lipophilicity of most HOPs renders their extraction difficult. Moreover, the simultaneous determination of multiple HOPs to achieve the high-throughput screening of these analytes is complex. In this study, a reliable and efficient pretreatment method based on ultrasound-assisted extraction, gel permeation chromatography purification, and ultra performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) was developed for the determination of 12 HOPs in edible fish. The procedures of sample extraction and purification and LC-HRMS detection parameters were optimized to improve the performance of the method. Fresh fish samples were thoroughly rinsed with water, and non-edible parts, including the skin, bones, and phosphorus, were removed. The fish were weighed, cut into small pieces, and vacuum freeze-dried for 48 h. Subsequently, a freeze grinder was used to grind the dried fish into a fine powder. Exactly 2 g of the fish powder was weighed, fortified with isotope-labeled internal standards of the HOPs, and allowed to stand for 5 min. Methanol-acetonitrile (1∶1, v/v) was then added, followed by vortex mixing and ultrasonication. After centrifugation, the supernatant was transferred to a fresh tube. The extraction process was repeated twice and all extracts were combined. The extract was evaporated under a gentle nitrogen flow and redissolved in a mixture of ethyl acetate-cyclohexane (1∶1, v/v). The sample mixture was cleaned using gel permeation chromatography, and the eluate was collected and concentrated under a nitrogen flow. Sample residuals were reconstituted with water-methanol (1∶1, v/v) prior to instrumental analysis. Chromatographic separation was performed using an ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm). Water containing 2 mmol/L NH4Ac and acetonitrile were used as the mobile phases, and an optimized gradient elution program was applied. Isotope dilution and an internal standard method were used to quantify the HOPs. An electrospray ionization source operated in negative mode was applied to ionize the HOPs, and a full scan together with data-dependent acquisition (DDA) was applied for HRMS. Excellent linearities (R2>0.99) were obtained for all HOPs in the quantification range of 1.0-1000.0 ng/mL. The limits of quantification were 0.5 ng/g. The analytical method was validated using pooled fish samples fortified with HOP standards (4, 40, and 400 ng/g). The recoveries of the HOPs were in the range of 67.6%-133.8%, and the corresponding RSDs were 0.5%-15.6%. A total of 27 commercially available fish samples were analyzed using the developed method, and the results revealed the presence of HOPs in the fish, indicating the practicability of the method for real-world samples. The developed method is rapid, accurate, precise, and suitable for detecting HOPs in fish. This study provides a useful approach for environmental monitoring and food safety assurance by enabling the accurate and efficient analysis of HOPs in commonly consumed fish. Given increasing global concerns over HOPs, the method developed in this study will provide practical technical support for consumers aiming to reduce their exposure to and the adverse impacts of HOPs via fish.

The effects of chicken hydrolyzed proteins in extruded diets on plasma and fecal metabolic profiles in adult dogs

Research has shown various hydrolyzed proteins possessed beneficial physiological functions; however, the mechanism of how hydrolysates influence metabolism is unclear. Therefore, the current study aimed to examine the effects of different sources of protein hydrolysates, being the main dietary protein source in extruded diets, on metabolism in healthy adult dogs. Three complete and balanced extruded canine diets were formulated: control chicken meal diet (CONd), chicken liver and heart hydrolysate diet (CLHd), mechanically separated chicken hydrolysate diet (CHd). A replicated 3 × 5 Latin rectangle design was used with 10 adult beagles. Within each period, the assigned diets were fed to the beagles for 28 days after a 7-day wash out period. Plasma and fresh fecal samples were collected at day 28. Samples of diets, plasma, and feces were analyzed for global metabolomics with ultra-performance liquid chromatography and quadrupole-Orbitrap high-resolution mass spectrometer interfaced with a heated electrospray ionization source and mass analyzer. In general, there were lower fecal concentrations of dipeptides and protein degradation metabolites, indicating higher protein digestibility, in dogs fed protein hydrolysate diets in contrast with CONd (q < 0.05). Higher plasma pipecolate and glutamate, higher fecal spermidine and indole propionate, and lower phenol-derived products in both plasma and feces were found in CLHd group than CONd (q < 0.05), indicating lower oxidative stress and inflammation levels. The main difference in lipid metabolism between CHd and CONd was the bile acid metabolism, showing lower circulating bile acid, lower unconjugated bile acid excretion and higher taurine-conjugated bile acid excretion in the CHd group (q < 0.05). In conclusion, using chicken hydrolysates as the main protein source in extruded canine diets showed potential for physiological benefits in healthy adult dogs, especially protein hydrolysate from chicken heart and liver demonstrated effects on lowering inflammation and oxidation levels.

Rapid Determination of Water-Soluble Vitamins in Human Serum by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry.

Water-soluble vitamins play essential roles in normal body functions and metabolic activities. However, few methods have simultaneously measured all nine water-soluble vitamins in biological matrices. In this study, we developed a sensitive and accurate method for the simultaneous measurement of thiamine (B1), riboflavin (B2), nicotinamide (B3), pantothenic acid (B5), 4-pyridoxic acid (B6), biotin (B7), 5-methyltetrahydrofolic acid (B9), ascorbic acid (VC), and methylmalonic acid (MMA) in human serum. Samples were analyzed using ultrahigh-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with Waters HSS T3 and BEH C18 columns, each measuring 2.1 × 50 mm with a particle size of 1.7 μm. The mass spectrometer was equipped with an electrospray ionization source, and optimized multiple reaction monitoring was employed to detect all compounds in positive ionization mode. The capillary voltage was set at 0.5 kV. Nitrogen was used as the desolvation gas, with a flow rate of 1000 L/h at 500 °C. Argon was used as the collision gas. The method's performance was validated according to the Clinical and Laboratory Standards Institute guidelines assessing linearity, limit of quantitation, precision, accuracy, carryover, matrix effects, recovery, and dilution. The results confirmed the successful validation of this method for water-soluble vitamins in serum. However, the presence of common endogenous interferences and the type of blood collection tube influenced the results for certain water-soluble vitamins. The results showed that this method was satisfactory, offering significant improvements in analytical performance, including shorter analysis time, higher sensitivity, and the requirement of a smaller sample volume.

MS SIEVE-Pushing the Limits for Biomolecular Mass Spectrometry.

Electrospray mass spectrometry has become indispensable in many disciplines including the classic "omics" techniques such as proteomics or lipidomics, as well as other life science applications in molecular, cellular, and structural biology. However, a limiting factor that often arises for the detection of biomolecular analytes is their poor ionization efficiency in the ion source. Here, we present an add-on device for the electrospray source, termed MS SIEVE (MS Spectral Impurity Eliminator & Value Enhancer), which is placed between the electrospray needle and the cone of the mass spectrometer. We probed the application of MS SIEVE for various biomolecules including proteins, peptides, lipids, glycans and DNA oligonucleotides and even synthetic polymers such as polyethylene glycol and found that MS SIEVE selectively improves the signal intensity, while suppressing the spectral contribution of contaminants such as NaCl. Importantly, MS SIEVE can, in principle, be adapted for any electrospray ion source and, therefore, represents a promising alternative for routine "omics" methods as well as special applications on challenging analytes.

LC-MS/MS method for the simultaneous determination of six phenolic acids in rat plasma and hypoglycemic effects in normal and T2DM rats after oral administration of Eleutherococcus senticosus fruits extract

AbstractEleutherococcus senticosus (Rupr. &amp; Maxim.) Maxim. fruits (ESF) is a natural health food that has been widely used in traditional medicine. This study aimed to establish and validate a rapid and sensitive method for determining of six phenolic acids in plasma of normal and T2DM rats by ultra-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). Separation and quantification were performed on a Waters HSS T3 column (100 × 2.1 mm, 1.8 μm) with water (A) and methanol (B). The electrospray ionization (ESI) source was operated in negative ionization mode. Multiple reaction monitoring (MRM) was used to quantitatively analyzed hyperoside m/z 463.2→301.1, caffeic acid m/z 179.1→135.1, chlorogenic acid m/z 353.2→190.9, gallic acid m/z 169.0→125.1, protocatechuic acid m/z 153.1→109.1, and isofraxidin m/z 221.1→191.0, respectively. The hypoglycemic effect of ESF was verified by determining blood glucose and lipid levels in a type 2 diabetes model. This study laid the foundation for exploring ESF clinical guidelines in the future.

Qualitative and quantitative analysis of chemical components of Dracocephalum moldavica based on UPLC-Q-TOF-MS/MS and UPLC

Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS) was used to rapidly identify the chemical components in Dracocephalum moldavica, and UPLC was employed to determine the content of its main components. MS analysis was performed using an electrospray ionization(ESI) source and data were collected in the negative ion mode. By comparing the retention time and mass spectra of reference compounds, and using a self-built compound database and the PubChem database, 68 compounds were identified from D. moldavica, including 36 flavonoids, 22 phenylpropanoids, 4 phenols, and 6 other compounds. On this basis, a UPLC quantitative method was established to simultaneously determine 8 main components, i.e., luteolin-7-O-glucuronide, apigenin-7-O-glucuronide, rosmarinic acid, diosmetin-7-O-glucuronide, tilianin, acacetin-7-O-glucuronide, acacetin-7-O-(6″-O-malonyl)-glucoside, and acacetin. A Waters ACQUITY BEH C_(18) column(2.1 mm × 100 mm, 1.7 μm) was used, with acetonitrile and a water solution containing 0.1% formic acid and 0.1% phosphoric acid as the mobile phase for gradient elution. The detection wavelength was set at 330 nm, with a flow rate of 0.4 mL·min~(-1), and the column temperature was maintained at 35 ℃. The 8 components demonstrated good linearity(r≥0.999 9) over a wide mass concentration range(50 or 100 times). The average recovery rate ranged from 97.5% to 105.1%, and the relative standard deviations(RSDs) were 0.90% to 3.4%(n= 6), indicating that the method was simple, accurate, and reliable. In 17 batches of D. moldavica samples, the content of these 8 components ranged from 0.405 to 2.10, 0.063 to 0.342, 0.446 to 2.43, 0.415 to 1.47, 1.57 to 4.34, 0.173 to 0.386, 1.00 to 5.40, and 0.069 to 0.207 mg·g~(-1), respectively. These results indicate significant differences in the internal quality of the samples, highlighting the need for strict quality control to ensure their pharmacodynamic efficacy. This study provides a scientific basis for the rapid discovery of pharmacodynamic substances, comprehensive quality control, and the formulation or revision of quality standards for D. moldavica.