Ion Trap Mass Spectrometry Research Articles

Determination of lipophilic marine biotoxins in shellfish foods by ultra performance liquid chromatography-hybrid triple quadrupole linear ion trap-mass spectrometry

An ultra performance liquid chromatography-hybrid triple quadrupole linear ion trap-mass spectrometry(UPLC-QqLIT-MS) was established for determination of lipophilic marine biotoxins in shellfish. And the 12 lipophilic marine biotoxins in shellfish were surveyed. The lipophilic marine biotoxins in homogenized shellfish were ultrasonically extracted by methanol in super-sonic instrument, and cleaned up by solid phase extraction of Strata-X column, and eluted with methanol(containing 0.3% ammonia water). The elution was diluted with water, and cleaned by 0.22 μm millipore filter. The filtrate was separated on a Waters ACQUITY UPLC BEH C_(18) column(150 mm×2.1 mm, 1.7 μm)by gradient elution in 12 minutes with acetronitrile-water(containing 0.01%(V/V) ammonia and 2 mmol/L ammonium formate) as mobile phase, and detected by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS), identified by electrospray ionization(ESI) in simultaneous scanning mode of positive and negative ions using multiple reaction monitoring, and quantified with external standards. Information dependent acquisition scan function(IDA) combined with enhanced production scan(EPI) was used to confirm the 12 lipophilic marine biotoxins. The calibration curves of 12 lipophilic marine biotoxins showed good linearity in the range of 0.5-50 μg/L with correlation coefficients were 0.9984-0.9999.The detection limits of the method were 0.15-0.29 μg/kg. The recoveries of three spiking levels ranged from 80.0% to 116.0%, and the relative standard deviation(RSD) were 0.6%-6.4%(n=7). The method for determination of 12 lipophilic marine biotoxins in shellfish by UPLC-QqLIT-MS was of operation convenience, less interference from impurities and good accuracy, which could meet the requirements for the determination of 12 lipophilic marine biotoxins residues in sea foods.

Investigation of solvent microparticle formation in spray ionization–quadrupole ion trap–mass spectrometry

AbstractIn the present study, a new method has been developed for the real‐time analysis of insource created solvent particles based on spray ionization–quadrupole ion trap–mass spectrometry (SI‐QIT‐MS). This is the first work in the literature reporting the formation of different solvent particles during solvent spray in mass spectrometry. The solvent particles formed from the solvent droplets are detected by a charge detector. Our ion trap system allows the measurement of a wide range particle masses. Various solvents and solvent mixtures such as water, methanol, acetone, toluene, n‐butanol, water‐methanol, and water‐ethanol were sprayed through a cone system, and the mass of the particles was monitored by different trap frequencies and voltages. While polar molecules produce larger and more diverse particles due to their strong intermolecular forces, apolar solvents generally do not produce a significant number of particles. We obtained results using a homemade ion trap mass spectrometer capable of determining the mass of micro‐sized solvent and solvent mixture particles weighing up to 1015 (Da). The instrument uses a charge detector connected to the exit of the ion trap. Simultaneous acquisition of particle mass spectra and measurement of the amount of charge in each particle allow mass assignment of each particle. Sprayed solvent particles were examined at various trap frequencies and voltages to find the best instrumental parameters for the highest trapping efficiency. The custom SI‐QIT‐MS instrument allows the measurement of the mass distribution of charged particles from the solvent spray.

Simultaneous quantitative analysis of nine saponins in Gynostemma pentaphyllum before and after heat processing based on UPLC-Q-Trap-MS

Heat-processed Gynostemma pentaphyllum has strong biological activity, and saponins are the main components. To investigate the changes of saponins in G. pentaphyllum before and after heat processing, the present study determined and analyzed the content of nine saponins in G. pentaphyllum from Zhangzhou of Fujian and Jinxiu of Guangxi by ultra-high performance liquid chromatography with quadrupole ion-trap mass spectrometry(UPLC-Q-Trap-MS). The separation of the analytes was performed on an ACQUITY UPLC BEH C_(18) column(2.1 mm×50 mm, 1.7 μm) at 30 ℃, with acetonitrile and 0.1% formic acid in water as the mobile phase by gradient elution, and the flow rate was 0.3 mL·min~(-1). Quantitative analysis was performed using electrospray ionization source(ESI) in the multiple reaction-monitoring(MRM) mode. The results showed that the content of saponins with biological activities increased after heat processing. Specifically, gypenoside L, gypenoside LI, damulin A, damulin B, ginsenoside Rg_3(S), and ginsenoside Rg_3(R) in G. pentaphyllum produced in Zhangzhou of Fujian increased by 7.369, 8.289, 12.155, 7.587, 0.929, and 1.068 μg·g~(-1), respectively, while the content of ginsenoside Rd, gypenoside LVI, and gypenoside XLVI, which were abundant in the raw materials, decreased by 0.779, 19.37, and 9.19 μg·g~(-1), respectively. The content of gypenoside L, gypenoside LI, damulin A, damulin B, ginsenoside Rg_3(S), and ginsenoside Rg_3(R) in G. pentaphyllum produced in Jinxiu of Guangxi increased by 0.100, 0.161, 0.317, 0.228, 3.280, and 3.395 μg·g~(-1), respectively, while the content of ginsenoside Rd, gypenoside LVI, and gypenoside XLVI in the raw materials was reduced by 1.661, 0.014, and 0.010 μg·g~(-1), respectively. The results suggest that heat processing is an effective way to transform rare gypenosides. Furthermore, it is found that there are great differences in the content of gypenosides in different regions.

Levels of T-2 toxin and its metabolites, and the occurrence of Fusarium fungi in spring barley in the Czech Republic

Mycotoxins have been widely studied by many research groups but further multidisciplinary research is needed to better understand and clarify many issues. This study describes the use of high-performance liquid chromatography coupled with ion trap mass spectrometry (HPLC-MS) to measure T-2 toxin and its metabolites, such as HT-2 toxin, neosolaniol (NEO) and diacetoxyscirpenol (DAS), as well as masked glucosylated mycotoxins in Fusarium-infected Czech spring barley. In total, 152 spring barley samples from the 2018 harvest were analyzed by the ELISA screening method for the presence of T-2 toxin. The most contaminated samples (15), which exceeded the recommended maximum level set by the EU for the sum of T-2 and HT-2 toxin in unprocessed cereals (200 μg/kg), were analyzed by HPLC-MS/MS and microbiological testing. Isolated fungi were evaluated microscopically and identified by polymerase chain reaction (PCR) assays. The prevalence of Fusarium species in spring barley across the Czech Republic in 2018 showed a predominance of F. poae (12 barley samples) and F. tricinctum (9 barley samples). Other strains (F. sporotrichioides and F. langsethiae) were present at a lower frequency, in 1 and 2 samples, respectively. The average concentration of T-2 plus HT-2 toxin was 107.7 μg/kg, while NEO and DAS were found in a few samples at values close to their limit of quantification. HT-2 glucoside was identified in all samples.

"Source-Induced Dissociation Vs Collision-Induced Dissociation Fragmentation Behavior of Four Antiviral Drugs in a Liquid Chromatography Ion-Trap Mass Spectrometry"

Mass spectrometry (MS) is an important tool for analyzing or detecting a wide range of organic, inorganic, natural, unnatural molecules, especially drugs, proteins, peptides are of interests beside routine analysis..

Phytochemical Analysis of Phenolics, Sterols, and Terpenes in Colored Wheat Grains by Liquid Chromatography with Tandem Mass Spectrometry.

The colored grain of wheat (Triticum aestivum L.) contains a large number of polyphenolic compounds that are biologically active ingredients. The purpose of this work was a comparative metabolomic study of extracts from anthocyaninless (control), blue, and deep purple (referred to here as black) grains of seven genetically related wheat lines developed for the grain anthocyanin pigmentation trait. To identify target analytes in ethanol extracts, high-performance liquid chromatography was used in combination with Bruker Daltonics ion trap mass spectrometry. The results showed the presence of 125 biologically active compounds of a phenolic (85) and nonphenolic (40) nature in the grains of T. aestivum (seven lines). Among them, a number of phenolic compounds affiliated with anthocyanins, coumarins, dihydrochalcones, flavan-3-ols, flavanone, flavones, flavonols, hydroxybenzoic acids, hydroxycinnamic acids, isoflavone, lignans, other phenolic acids, stilbenes, and nonphenolic compounds affiliated with alkaloids, carboxylic acids, carotenoids, diterpenoids, essential amino acids, triterpenoids, sterols, nonessential amino acids, phytohormones, purines, and thromboxane receptor antagonists were found in T. aestivum grains for the first time. A comparative analysis of the diversity of the compounds revealed that the lines do not differ from each other in the proportion of phenolic (53.3% to 70.3% of the total number of identified compounds) and nonphenolic compounds (46.7% to 29.7%), but diversity of the compounds was significantly lower in grains of the control line. Even though the lines are genetically closely related and possess similar chemical profiles, some line-specific individual compounds were identified that constitute unique chemical fingerprints and allow to distinguish each line from the six others. Finally, the influence of the genotype on the chemical profiles of the wheat grains is discussed.

Toxic plants-Detection of colchicine in a fast systematic clinical toxicology screening using liquid chromatography-mass spectrometry.

Colchicum autumnale, which can be mistaken for Allium ursinum, contains the alkaloid colchicine potentially leading to life-threatening up to fatal intoxications. We report two cases of acute intoxications with unexplained circumstances. Using the authors' systematic screening approaches, colchicine could be detected in blood plasma and urine samples using liquid chromatography coupled to linear ion trap mass spectrometry (LC-ITMSn ) and high-resolution tandem mass spectrometry (LC-HRMS/MS). Metabolites of colchicine could be identified in urine for confirmation of screening results. Gas chromatography-mass spectrometry (GC-MS) analysis was also conducted, but colchicine could not be detected. Furthermore, colchicine concentration was estimated via LC-HRMS/MS in plasma samples. Results of the systematic screening indicated the ingestion of colchicine from both subjects. In both cases, the parent compound was detected in blood plasma and urine using the LC-HRMS/MS and LC-ITMSn system. An O-demethylation metabolite was identified in urine samples of both subjects using LC-HRMS/MS; the N-deacetylation product was also found in urine samples of both cases via LC-HRMS/MS and LC-ITMSn . The use of LC-ITMSn resulted only in the detection of the O-demethylation product in case 2. Plasma concentrations were estimated at 2.5ng/ml and 4.7ng/ml for cases 1 and 2, respectively. We demonstrated the detection of this highly toxic alkaloid in blood plasma and urine using a time-saving and reliable clinical systematic screening. Furthermore, we identified metabolites of colchicine being rarely discussed in literature, which can be used as additional screening targets.

Carpobrotus edulis (L.) N.E.Br. extract as a skin preserving agent: From traditional medicine to scientific validation

ObjectiveCarpobrotus edulis (L.) N.E.Br. is a succulent perennial plant native to South Africa and grows invasively in the Mediterranean basin. It is commonly used for the treatment of various diseases, including skin wound healing and regeneration, for which experimental validation is lacking. We therefore evaluated the skin healing properties by testing a C. edulis aqueous leaf extract (CAE) on cell cultures and in enzymatic assays. MethodsMicro-morphological analysis of leaves was carried out using scanning electron microscopy and light microscopy. Phytochemical features and antioxidant activity of CAE were evaluated by reversed-phase liquid chromatography coupled with diode array detection and electrospray ion trap mass spectrometry (RP-LC-DAD-ESI-MS), and in vitro cell-free assays. Biological activities were evaluated using keratinocytes and fibroblasts, as well as elastase, collagenase, and hyaluronidase. ResultsCAE showed high carbohydrates (28.59% ± 0.68%), total phenols ([101.9 ± 6.0] g gallic acid equivalents/kg dry extract [DE]), and flavonoids ([545.9 ± 26.0] g rutin equivalents/kg DE). RP-LC-DAD-ESI-MS revealed the predominant presence of hydroxycinnamic acids (51.96%), followed by tannins (14.82%) and flavonols (11.32%). The extract was not cytotoxic, had a strong and dose-dependent antioxidant activity, and inhibited collagenase (> 90% at 500 µg/mL) and hyaluronidase (100% at 1000 µg/mL). In cell culture experiments, CAE increased wound closure and collagen production, which was consistent with its high polyphenol content. ConclusionOur data support the use of the C. edulis for skin care and the treatment of skin problems. Moreover, use of C. edulis for skin care purposes could be an eco-friendly solution to reduce its invasiveness in the environment.

Comparison of LC–MS3 and LC–MRM strategy for quantification of methotrexate in human plasma and its application in therapeutic drug monitoring

A simple, highly selective and high throughput liquid chromatography tandem mass spectrometry cubed (LC/MS3) method was developed and validated for quantification of methotrexate in human plasma. The MS3 detection is a scanning mode of QTrap MS systems or ion trap MS systems. After simple protein precipitation with methanol, methotrexate and methotrexate-d3 were separated on an Agilent Poroshell 120 SB-C18 column (4.6 × 50 mm, 2.7 µm) using isocratic elution with a mobile phase consisting of 60% 0.1% formic acid in water and 40% 0.1% formic acid in acetonitrile. The flow rate is 0.8 mL/min. MS3 detection in positive ion mode used the MRM3 transitions at m/z 455.2→308.2→175.1 for quantification of methotrexate and m/z 458.2→311.2→175.1 for quantification of methotrexate-d3. The total run time was only 3 min for each sample. The LC/MS3 assay was linear in the concentration range 10–3000 ng/mL(R2 ≥ 0.995) and the intra- and inter-day accuracies were< 3.72% and precisions were< 7.78% at all concentrations. The absolute recoveries (%) and matrix effect (%) for methotrexate in human plasma were between 92.6 and 114.3. The novelty of the presented methodology is the MS3 technique resulting in enhanced selectivity and sensitivity. The application of this LC-MS3 method was successfully completed on 46 human plasma samples and the quantitative results of identical human plasma samples were compared with another LC-MRM based method. Passing–Bablok regression coefficients demonstrated that there is no significant difference between the LC-MS3 method and LC-MRM method. Bland–Altman plots showed a concordant results, supporting the developed LC–MS3 method is a reliable and accurate assay for determination of methotrexate in human plasma. This work is also a proof of concept for using LC-MS3 technique to determination of chemicals in biological samples.

Isotope-Coding Derivatization for Quantitative Profiling of Reactive α-Dicarbonyl Species in Processed Botanicals by Liquid Chromatography-Tandem Mass Spectrometry.

α-Dicarbonyls (α-DCs) are key reactive Maillard intermediates with structural diversity and are widely found in foods and in vivo, but little is known regarding the complete molecular profiles of these potentially harmful electrophiles. Herein, we reported a novel isotope-coding derivatization (ICD) strategy for the broad-spectrum, quantitative profiling of (non)target α-DC species in natural foodstuffs. It utilized differential isotope labeling (DIOL) with a reagent pair o-phenylenediamine (OPD)/OPD-d4 (deuterated) to form stable quinoxalines for class-specific fragmentation-dependent acquisition using liquid chromatography-hybrid quadrupole linear ion trap mass spectrometry (LC-QqLIT). A combination of facile one-pot quantitative labeling and convenient cleanup protocol afforded satisfactory sensitivity, linearity, accuracy (81-116%), and process recovery (86-109% with RSDs < 10%) by matrix-matched ICD-internal standard calibration, without significant matrix interference (-9 to 5%), isotopic effect (<0.5%), and cocktail effect. A more generic DIOL-based LC-QqLIT algorithm integrated double precursor ion and neutral loss scan to trigger enhanced product ions with the unique isobaric doublet tags (4 Da shift), enabling simultaneous screening and relative quantitation of nontarget α-DC analogues in a single analysis. This study has widened the vision on complex α-DC profiles in traditional botanicals, which revealed a wide occurrence of α-DCs in such processed sugar-rich products, yet their abundance varied greatly among different samples.

Parallel Coupling of Ion Mobility Spectrometry and Ion Trap Mass Spectrometry for the Real-Time Alarm Triggering and Identification of Hazardous Chemical Leakages.

Hazardous chemical leakages involved in chemical terrorist attacks and chemical industrial accidents have been posing severe threats to human health and the environment. Vehicle-mounted mass spectrometry (MS) has been developed for continuous, on-road measurements to map the spatial and temporal distributions of hazardous chemicals. However, the detection of chemicals with small temporal scales and spatial scales is always challenging. In this study, a parallel coupling apparatus combining the techniques of ion mobility spectrometry and ion trap MS (p-IMS-ITMS) was developed to improve the detection rate and the time response capability of a stand-alone ITMS system for short time-span chemical tracking. A workflow was also proposed along with the apparatus, where the ITMS system can be triggered, as chemical suspects were discovered with the IMS system. The sampling positions of the ITMS system were investigated and optimized. In addition, a strategy was proposed to diminish the time span of samples from 1.5 to 0.5 s for evaluating the performances of the p-IMS-ITMS system. The detection rate of the stand-alone ITMS system was measured to be only 9.5, 32, and 87.5% for the time span of 0.5, 1, and 1.5 s, respectively. By comparison, the detection rates of the p-IMS-ITMS system were 99.5, 100, and 100%, where the detection rate was increased by a factor of 10 for 0.5 s time span. Moreover, the addition of an IMS system could provide temporal patterns of hazardous chemicals with a resolution of 33 ms. Finally, the potential of the p-IMS-ITMS system for environmental navigation monitoring and assessment was further demonstrated by detecting the leakages of dimethyl methyl phosphonate and dipropylene glycol monomethyl ether.

Quick determination of Glyphosate and AMPA at sub µg/L in drinking water by direct injection into LC-MS/MS

A sensitive, simple and quick method for the determination of glyphosate (Gly) and its degradation product, Aminomethyl phosphonic acid (AMPA), in water through ion chromatography coupled to quadrupole-linear ion trap mass spectrometry has been developed. Sample treatment was based on direct injection and acquisition was implemented in both MS2 and MS3 modes. The LoQs of the method were 0.03 µ/L for both Gly-and AMPA. The recoveries were between 91 and 118% and RSD was lower than 15%. The developed methodology was applied on 436 water samples.

Urinary Bisphenol A Concentrations and Parameters of Ovarian Reserve among Women from a Fertility Clinic.

Background: Human exposure to environmentally widespread endocrine disruptors, especially bisphenol A (BPA), has been suggested to affect reproductive health. Animal studies indicate that BPA may play a role in the process of reproduction and impact on maturing oocytes, meiotic cell division or fertilization rate. Nevertheless, data regarding the effects of exposure to BPA on women’s ovarian function are still limited. Therefore, the aim of the current study is to assess the effects of environmental exposure to BPA on ovarian reserve. Methods: The study participants consisted of 511 women in reproductive age (25–39 years) who attended an infertility clinic for diagnosis, due to the couples’ infertility. BPA urinary concentrations were assessed by the validated gas chromatography ion-trap mass spectrometry method. The ovarian reserve was assessed using ovarian reserve parameters: Hormones concentrations: E2 (estradiol), FSH (follicle stimulating hormone), AMH (anti-Müllerian hormone), and AFC (antral follicle count). Results: In the present study, the negative association between BPA urinary concentrations and AMH (p = 0.02) and AFC (p = 0.03) levels was found. Exposure to BPA was not related to other examined parameters of ovarian reserve (FSH, E2). Conclusions: Our results suggest that BPA exposure may affect women ovarian reserve parameters and reduce ovarian reserve. As this is one of the first studies of its kind, the findings need confirmation in a further investigation.

A targeted prenylation analysis by a combination of IT-MS and HR-MS: Identification of prenyl number, configuration, and position in different subclasses of (iso)flavonoids

Prenylated (iso)flavonoids are potent bioactive compounds found in the Fabaceae family. Analysis and quantification of this type of phytochemicals is challenging due to their large structural diversity. In this study, the fragmentation of prenylated (iso)flavonoids was investigated using electrospray ionization ion trap mass spectrometry (ESI-IT-MSn) with fragmentation by collision induced dissociation (CID) in combination and Orbitrap-MS (ESI-FT-MS2) with fragmentation by higher energy C-trap dissociation (HCD). With this combination of IT-MSn and high resolution MS (FT-MSn), it was possible to determine the fragmentation pathways and characteristic spectral features of different subclasses of prenylated (iso)flavonoid standards, as well as characteristic fragmentations and neutral losses of different prenyl configurations. Based on our findings, a decision guideline was developed to (i) identify (iso)flavonoid backbones, (ii) annotate prenyl number, (iii) configuration, and (iv) position of unknown prenylated (iso)flavonoids, in complex plant extracts. In this guideline, structural characteristics were identified based on: (i) UV absorbance of the compound, (ii) mass-to-charge (m/z) ratio of the parent compound; (iii) ratio of relative abundances between neutral losses 42 and 56 u in MSn; (iv) retro-Diels-Alder (RDA) fragments, neutral losses 54 and 68 u, and the ratio [M+H–C4H8]+/[M+H]+. Using this guideline, 196 prenylated (iso)flavonoids were annotated in a Glycyrrhiza glabra root extract. In total, 75 skeletons were single prenylated, 104 were double prenylated, and for merely 17 skeletons prenyl number could not unambiguously be annotated. Our prenylation guideline allows rapid screening for identification of prenylated (iso)flavonoids, including prenyl number, configuration, and position, in complex plant extracts. This guideline supports research on these bioactive compounds in the areas of plant metabolomics and natural products.

An LC-MS/MS method for simultaneous quantification of 11 components of Xian-Xiong-Gu-Kang in the plasma of osteoarthritic rats and pharmacokinetic analysis.

Xian-Xiong-Gu-Kang is composed of Epimedium brevicornu, Ligusticum chuanxiong, Radix clematidis, Cinnamomum cassia, and Fructus xanthii. It is used to treat numbness and pain of limbs. In this study, we developed a method to simultaneously quantify 11 components of Xian-Xiong-Gu-Kang (icarrin, epimedin A, epimedin B, epimedin C, icariside II, chlorogenic acid, ligustilide, senkyunolide A, senkyunolide I, ferulic acid, and cinnamic acid) in rat plasma using ultra-performance liquid chromatography coupled with quadrupole linear ion trap mass spectrometry. Chromatographic separation was performed on an ACQUITY UPLC BEH C18 column using gradient elution with a mobile phase comprising acetonitrile and 0.05% (v/v) formic acid aqueous solution. Mass spectrometry detection was performed using positive and negative electrospray ionization in the multiple reaction monitoring mode. The calibration curves of the 11 constituents were linear, with correlation coefficients>0.99. The intra- and interday accuracy and precision values were within ±15.0%. The extraction recoveries of the 11 constituents and two internal standards were between 66.05 and 105.40%, and the matrix effects were between 86.74 and 112.86%. Using this method, the pharmacokinetic features of the 11 constituents were elucidated in the plasma of osteoarthritic rats after oral administration of the Xian-Xiong-Gu-Kang extract.

Atmospheric Pressure Drift Tube Ion Mobility Spectrometry Coupled with Two-Dimensional Tandem Mass Spectrometry.

Atmospheric pressure drift tube ion mobility was coupled with two-dimensional tandem mass spectrometry (2D MS/MS) in a linear ion trap to simultaneously collect ion mobility and the entire MS/MS data domain. Utilizing ion intensities from precursor ion and neutral loss scan lines, ion mobility spectra of multiple compounds with particular functional groups were acquired in a single experiment. Functional group-specific ion mobility spectra were demonstrated for a standard mixture of lipids. Additionally, ion mobility was used to separate isobaric ions prior to 2D MS/MS. The combination of these two methods offers improvements for the analysis of complex mixtures.

Study on the Analytical Method of Solid Phase Extraction-Ultra Performance Liquid Chromatography Tandem Quadrupole Linear Ion Trap Mass Spectrometry for 12 Perfluorinated Compounds in Human Urine

To establish a method for simultaneous determination of 12 kinds of perfluorinated compounds (PFCs) in human urine based on ultra performance liquid chromatography tandem quadrupole linear ion trap mass spectrometry (UPLC-QTtrap-MS). After pH adjustment with 2% formic acid, the urine samples were loaded on a WAX solid phase extraction (SPE) cartridge for extraction, purification and concentration. The eluates were collected, concentrated to dryness under nitrogen, and reconstituted with 10 mmol/L ammonium acetate aqueous solution-methanol ( V water∶ V methanol = 70∶30) before injection. UPLC was performed on a C 18 cartridge, and methanol and 10 mmol/L ammonium acetate aqueous solution was used as mobile phases with gradient elution. QTtrap-MS was operated in multiple reaction monitoring (MRM) mode, and the internal standard calibration curves were applied for quantitative analysis. Good linearity was obtained in the linear range, with the method detection limits and method quantification limits being 0.032 ng/L-6.5 ng/L and 0.10 ng/L-21 ng/L, respectively, for the 12 kinds of PFCs. The spiked recoveries of the 12 kinds of PFCs were 91.5%-114%, with the intra-day precision and the inter-day precision being 0.57%-16.0% and 1.88%-20.1%, respectively. The established method was applied to the determination of 12 kinds of PFCs in the urine samples of primary school students collected in one area. Nine kinds of PFCs were detected in the urine samples in this area. Among the PFCs detected, perfluorobutanesulfonic acid (PFBS) and perfluorooctanoic acid (PFOA) were the main PFCs found in the student urine samples. The method established in this study could be used to simultaneously examine 12 kinds of PFCs in urine. The method combined SPE with isotope internal standard correction and achieved good sensitivity and accuracy.

Vitamin D Repletion Mitigates Oxidative Stress Induced Pulmonary Artery Remodeling in Sickle Cell Disease

The lung is a primary target of end organ pathology in patients with sickle cell disease (SCD). Pulmonary artery remodeling, a common feature at autopsy in SCD, is characteristic of the pulmonary hypertension of SCD. In an autopsy cohort of 20 patients with SCD, we found that pulmonary artery remodeling was a pathology of the young patient. Patients with severe remodeling had less than a 15% probability of surviving to 25 years of age, whereas those with milder remodeling had an 80% probability of living beyond 50. Therefore, we wanted to understand the mechanisms underpinning pulmonary artery remodeling.Using benchtop ion trap mass spectrometry on extracted pulmonary proteins from the autopsy study, we screened for oxidative “fingerprints” (protein modifications) that were specific for SCD. We found that the lungs from patients with SCD carried a profound oxidative burden. Oxidative modifications arising from the hydroxyl (∙OH), superoxide (∙O2-) peroxynitrite (ONOO-),and eosinophil peroxidase were all significantly elevated compared to samples prepared from identical lung blocks from unaffected controls at autopsy. However, of the oxidative modifications detected, only the signature from peroxynitrite, 3-nitro tyrosine, (3-NT) could differentiate those SCD patients with profound pulmonary artery remodeling from those with milder forms of this pathology. After adjusting for age, the 3-NT content was increased 16 fold in the severely remodeled pulmonary tissues. Using immunohistochemistry, we found that 3NT was exquisitely localized to remodeling vessels and areas of smooth muscle proliferation. We assayed plasma proteins from patients with SCD at steady state and found a consistently elevated 3-NT content when compared to control plasma. The 3-NT containing proteins in living patients correlated strongly with NT-proBNP, but inversely with plasma free hemoglobin at steady state.Peroxynitrite, a strong smooth muscle mitogen, is formed via the reaction of NO with ∙O2-, therefore we reasoned that the presence of the superoxide radical was transforming NO into ONOO-. Extracellular (EC) superoxides are neutralized by EC-superoxide dismutases (SODs) to preserve the vaso-regulatory effects of NO. EC-SOD is tethered to the outer membrane of cells to allow for diffusion of NO without superoxide attack. Using immunohistochemistry, electron microscopy, and linear-ion trap mass spectrometry with comparative proteomics on paraffin-free lung tissue we noted, that pulmonary EC-SOD was 60-fold depleted in the remodeling pulmonary vessels and endothelium in patients with SCD at autopsy. The plasma of patients at steady state, compared to unaffected controls, however, contained increased, but inactive EC-SOD indicating an SCD-specific release of EC-SOD from the outer membrane of endothelial surfaces and into the plasma compartment.Using an in vitro culture of human pulmonary endothelial cells, we quantified EC-SOD on the cell surface using ELISA. Plasma from patients with SCD significantly reduced the amount of EC-SOD detectable on the endothelial cells. Plasma from healthy control subjects was without effect.We, and many other groups have demonstrated that patients with SCD have compromised flow mediated dilation (FMD) - an NO mediated process. We found that both plasma EC-SOD and 3-NT content of plasma proteins inversely correlated with FMD in patients with SCD. However, high dose vitamin D repletion (100,000 units ergocalciferol weekly) improved FMD within 8 weeks and reduced both plasma EC-SOD and 3NT content of plasma proteins, thus restoring NO function. After an 8 week washout period of the ergocalciferol, FMD values, plasma EC-SOD, and plasma 3-NT content returned to baseline, pathological steady state levels.Furthermore, plasma from the 8 week ergocalciferol treated patients lost the ability to deplete EC-SOD from the endothelial cell surface in vitro, whereas after the washout, plasma from the same subject effectively removed EC-SOD from the endothelial cells.Taken together these data suggest a new mechanism of pulmonary hypertension in patients with SCD, one in which NO in the presence of superoxide radical promotes pulmonary artery remodeling and predicts an early death. Vitamin D, through an as yet undetermined mechanism, appears to restore NO function, and re-localize EC-SOD to the appropriate vascular compartment. DisclosuresKutlar:Sancilio & Co (OMEG-411-02): Other: Chair of Data and Safety Monitoring Board; BlueBird Bio: Other: Member of Data Monitoring Committee; Reprixys Pharmaceuticals Corporation (formerly known as Selexys Pharmaceuticals Corporation, which is not affiliated with Selexis S.A.): Research Funding; Novartis: Research Funding.

LC-MS/MS Screening of Phenolic Compounds in Wild and Cultivated Grapes Vitis amurensis Rupr.

This work represents a comparative metabolomic study of extracts of wild grapes obtained from six different places in the Primorsky and Khabarovsk territories (Far East Russia) and extracts of grapes obtained from the collection of N.I. Vavilov All-Russian Institute of Plant Genetic Resources (St. Petersburg). The metabolome analysis was performed by liquid chromatography in combination with ion trap mass spectrometry. The results showed the presence of 118 compounds in ethanolic extracts of V. amurensis grapes. In addition, several metabolites were newly annotated in V. amurensis. The highest diversity of phenolic compounds was identified in the samples of the V. amurensis grape collected in the vicinity of Vyazemsky (Khabarovsk Territory) and the floodplain of the Arsenyevka River (Primorsky Territory), compared to the other wild samples and cultural grapes obtained in the collection of N.I. Vavilov All-Russian Institute of Plant Genetic Resources.

Simultaneous detection and quantification of explosives by a modified hollow cathode discharge ion source

Detection of explosives at trace levels is crucial for security purposes because of increasing worldwide terrorist threats at public places. Previously, a hollow cathode discharge (HCD) ion source has been fabricated for detection of explosives. Recently, the HCD ion source has been modified for a dual pressures operating system and coupled to a linear ion trap MS to analyze explosives simultaneously. Here, trinitrotoluene (TNT), nitroglycerin (NG), pentaerythritol tetranitrate (PETN) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) were taken as model explosive compounds and the mass spectra were recorded in the negative mode ionization. At the higher ion source pressure (~28.0–30.0 Torr), NG, PETN and RDX gave adduct ions with the NO3− ion while TNT showed the [TNT + NO3–HNO2]- (m/z 242) simultaneously. However, NG and PETN did not give any ion signals at the lower ion source pressure (~0.8–1.0 Torr) while TNT exhibited its molecular ion, [TNT]-• (m/z 227), as a major ion through electron attachment and RDX showed fragment ions that followed electron capture dissociation concurrently. The modified HCD ion source exhibited better sensitivity in simultaneous detection and quantification of the explosives. The NO3− and NO2− as reagent ions in the air HCD plasma form stable adduct ions with the NG, PETN and RDX even with TNT at the higher temperature (140–200 °C). The formation of the NO3−, NO2− in the HCD plasma also causes the formation of [TNT-H]- (m/z 226) at the higher ion source pressure. The inner metallic surface of the hollow tube assists the Birch reduction type reaction that results in the formation of hydride ion of the TNT, [TNT + H]- (m/z 228). No significant difference in the spectral pattern for simultaneous and individual measurements for the explosives was observed at the higher ion source pressure. Therefore, it may conclude that the present modified HCD ion source can be used for simultaneous detection and quantification of the explosive compounds at trace and/or ultra-trace levels using air as a carrier gas.