Mass Spectra Data Research Articles

Bioactive Compounds Investigation From Methanol Bark Extract of Pterocarpus marsupium Using GC-MS Analysis

Introduction: Medicinal plants still represent untapped sources of novel compounds with potential therapeutic effects for mitigating human maladies.Pterocarpus marsupium, commonly known as Bijasal, is a well-known drug in ayurvedic system of medicine. Materials and methods: The dried bark powder of P.marsupium was extracted by Soxhlet with methanol and analyzed by gas chromatography, while the mass spectra data of the compounds found in the extract was matched with the data available at National Institute of Standards and Technology (NIST) library. Results: The results of the GC-MS analysis provide different peaksdetermining the presence of 10 major phytocomponents, that are 1-Penten-3-one,1-(2,6,6-trimethyl-1-cyclohexen-1-yl)-; Geranyl isovalerate; 2-Pentadecanone,6, 10, 14-trimethyl;Cyclopropaneoctanal, 2-octyl-; Octadecanoic acid;10-Octadecanoic acid, methyl ester; Heptadecanoic acid, 16-methyl,-methyl ester; Phytol; 4,8,12,16-Tetramethyl heptadecan-4-olide; Dasycarpidan-1-methanol, acetate with different therapeutic activities. Conclusion: The presence of these bioactive compounds justifies that the Pterocarpus marsupiumcan offer a base for using this compound as herbal alternative for the synthesis and development of new drug to treat various infectious diseases. However, isolation of individual phytochemical constituents might be useful to formulate a new novel drug.

Entrapment of amino acids in gas phase surfactant assemblies: The case of tryptophan confined in positively charged (1R,2S)-dodecyl (2-hydroxy-1-methyl-2-phenylethyl) dimethylammonium bromide aggregates.

The ability of positively charged aggregates of the surfactant (1R,2S)-dodecyl(2-hydroxy-1-methyl-2-phenylethyl)dimethylammonium bromide (DMEB) to incorporate D-tryptophan or L-tryptophan in the gas phase has been investigated by electrospray ion mobility mass spectrometry (ESI-IM-MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T+ ) and deprotonated (T- ) tryptophan are effectively included into the aggregates, whereas, tryptophan in zwitterionic (T0 ) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones. The ability to incorporate tryptophan increases with the aggregation number and charge state of aggregates. More than 1 tryptophan species can be entrapped (aggregates including up to 5 tryptophan are observed). Collision induced dissociation experiments performed on the positively singly charged DMEB hexamer containing 1 T- show that at low collision energies the loss of a DMEB molecule is preferred with respect to the loss of the DMEB cation plus T- species which, in turn, is preferred with respect to the loss of mere tryptophan, suggesting that the deprotonated amino acid is preferentially located in proximity of a DMEB head group and with the ionic moiety pointing towards the core of the aggregate. The analysis of the collision cross sections (CCS) of bare and tryptophan containing aggregates allowed evaluating the contributions of tryptophan and bromide ions to the total aggregate CCS. No significant discrimination between D-tryptophan and L-tryptophan by the chiral DMEB aggregates has been evidenced by mass spectra data, CID experiments, and CCS values.

Phosphoproteome of Toxoplasma gondii Infected Host Cells Reveals Specific Cellular Processes Predominating in Different Phases of Infection.

The invasion of Toxoplasma gondii tachyzoites into the host cell results in extensive host cell signaling activation/deactivation that is usually regulated by the phosphorylation/dephosphorylation. To elucidate how T. gondii regulates host cell signal transduction, the comparative phosphoproteome of stable isotope labeling with amino acids in cell culture-labeled human foreskin fibroblast cells was analyzed. The cells were grouped (Light [L], Medium [M], and Heavy [H] groups) based on the labeling isotope weight and were infected with T. gondii for different lengths of time (L: 0 hour; M: 2 hours; and H: 6 hours). A total of 892 phosphoproteins were identified with 1,872 phosphopeptides and 1,619 phosphorylation sites. The M versus L comparison revealed 694 significantly regulated phosphopeptides (436 upregulated and 258 downregulated). The H versus L comparison revealed 592 significantly regulated phosphopeptides (146 upregulated and 446 downregulated). The H versus M comparison revealed 794 significantly regulated phosphopeptides (149 upregulated and 645 downregulated). At 2 and 6 hours post-T. gondii infection, the most predominant host cell reactions were cell cycle regulation and cytoskeletal reorganization, which might be required for the efficient invasion and multiplication of T. gondii. Similar biological process profiles but different molecular function categories of host cells infected with T. gondii for 2 and 6 hours, which suggested that the host cell processes were not affected significantly by T. gondii infection but emphasized some differences in specific cellular processes at this two time points. Western blotting verification of some significantly regulated phosphoprotein phosphorylation sites was consistent with the mass spectra data. This study provided new insights into and further understanding of pathogen-host interactions from the host cell perspective.

Upgraded Analytical Gas Composition Technique in the Tritium Fuel Cycle of JET

The JET Active Gas Handling System has designed and commissioned a new analytical gas chromatography system. The novel design included modification of a basic off-the-shelf gas chromatograph to become tritium compatible and incorporated customised hardware of seven detectors, seven switching valves and seven separation columns into one analytical gas analyser. The functionality of the new system was proven during the inactive commissioning phase and gas species including hydrogen isotope molecules (H2, HD and D2), air components and hydrocarbons up to decane, water and ammonia including mass spectrum data could successfully be analysed. The design of this system is unique and the first of its kind employed in a nuclear fusion laboratory.

Are neutral loss and internal product ions useful for top-down protein identification?

Neutral loss and internal product ions have been found to be significant in both peptide and protein tandem mass spectra and they have been proposed to be included in database search and for protein identification. In addition to common canonical b/y ions in collision-based dissociation or c/z ions in electron-based dissociation, inclusion of neutral loss and internal product ions would certainly make better use of tandem mass spectra data; however, their ultimate utility for protein identification with false discovery rate control remains unclear. Here we report our proteome-level utility benchmarking of neutral loss and internal product ions with tandem mass spectra of intact E. coli proteome. Utility of internal product ions was further evaluated at the protein level using selected tandem mass spectra of individual E. coli proteins. We found that both neutral loss and internal products ions do not have direct utility for protein identification when they were used for scoring of P Score; but they do have indirect utility for provision of more canonical b/y ions when they are included in the database search and overlapping ions between different ion types are resolved. Biological significanceTandem mass spectrometry has evolved to be a state-of-the-art method for characterization of protein primary structures (including amino acid sequence, post-translational modifications (PTMs) as well as their site location), where full study and utilization tandem mass spectra and product ions are indispensable. This primary structure information is essential for higher order structure and eventual function study of proteins.

Shotgun proteomics of the barley seed proteome

BackgroundBarley seed proteins are of prime importance to the brewing industry, human and animal nutrition and in plant breeding for cultivar identification. To obtain comprehensive proteomic data from seeds, total protein from a two-rowed (Conrad) and a six-rowed (Lacey) barley cultivar were precipitated in acetone, digested in-solution, and the resulting peptides were analyzed by nano-liquid chromatography coupled with tandem mass spectrometry.ResultsThe raw mass spectra data searched against Uniprot’s Barley database using in-house Mascot search engine identified 1168 unique proteins. Gene Ontology (GO) analysis indicated that the majority of the seed proteins were cytosolic, with catalytic activity and associated with carbohydrate metabolism. Spectral counting analysis showed that there are 20 differentially abundant seed proteins between the two-rowed Conrad and six-rowed Lacey cultivars.ConclusionThis study paves the way for the use of a top-down gel-free proteomics strategy in barley for investigating more complex traits such as malting quality. Differential abundance of hordoindoline proteins impact the seed hardness trait of barley cultivars.

Croton gratissimus Leaf Essential Oil Composition, Antibacterial, Antiplatelet Aggregation, and Cytotoxic Activities

ABSTRACTEssential oil hydrodistilled from the leaves of Croton gratissimus was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) to identify the constituents by comparison of their mass spectra (MS) data and linear retention indices (LRI) with literature. Forty constituents corresponding to 96.7% of the total oil content were identified from the oil sample. The major compounds were sabinene (14.6%), α-phellandrene (12.3%), β-phellandrene (10.7%), α-pinene (6.05%), and germacrene D (5.9%). The essential oil exhibited stronger antibacterial activity with minimum inhibitory concentration (MIC) of 0.6 mg.mL–1 (Staphylococcus aureus), 0.2 mg.mL–1 (S. faecalis), and 1.3 mg.mL–1 (Escherichia coli and Bacillus cereus). In the antiplatelet aggregation inhibitory activity, the oil displayed action against the induced platelet aggregation in the order collagen (IC50 < 1) > thrombin (IC50 1.18) > Adenosine diphosphate (IC50 2.32) > epinephrine (IC50 3.65). The lethal concentration (LC50) of the oil at 8.52 mg.mL–1 was toxic to Artemia salina.

A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG)

Abstract. We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG) system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes) (Zhang et al., 2014). Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF), where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins) are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS), TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level resolution on other bulk aerosol components commonly observed by the AMS.

IgTools: a toolkit for analysis of antibody repertoire from immunosequencing and mass spectra data

IgTools: a toolkit for analysis of antibody repertoire from immunosequencing and mass spectra data

WUFlux: an open-source platform for 13C metabolic flux analysis of bacterial metabolism.

BackgroundFlux analyses, including flux balance analysis (FBA) and 13C-metabolic flux analysis (13C-MFA), offer direct insights into cell metabolism, and have been widely used to characterize model and non-model microbial species. Nonetheless, constructing the 13C-MFA model and performing flux calculation are demanding for new learners, because they require knowledge of metabolic networks, carbon transitions, and computer programming. To facilitate and standardize the 13C-MFA modeling work, we set out to publish a user-friendly and programming-free platform (WUFlux) for flux calculations in MATLAB®.ResultsWe constructed an open-source platform for steady-state 13C-MFA. Using GUIDE (graphical user interface design environment) in MATLAB, we built a user interface that allows users to modify models based on their own experimental conditions. WUFlux is capable of directly correcting mass spectrum data of TBDMS (N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide)-derivatized proteinogenic amino acids by removing background noise. To simplify 13C-MFA of different prokaryotic species, the software provides several metabolic network templates, including those for chemoheterotrophic bacteria and mixotrophic cyanobacteria. Users can modify the network and constraints, and then analyze the microbial carbon and energy metabolisms of various carbon substrates (e.g., glucose, pyruvate/lactate, acetate, xylose, and glycerol). WUFlux also offers several ways of visualizing the flux results with respect to the constructed network. To validate our model’s applicability, we have compared and discussed the flux results obtained from WUFlux and other MFA software. We have also illustrated how model constraints of cofactor and ATP balances influence fluxome results.ConclusionOpen-source software for 13C-MFA, WUFlux, with a user-friendly interface and easy-to-modify templates, is now available at http://www.13cmfa.org/or (http://tang.eece.wustl.edu/ToolDevelopment.htm). We will continue documenting curated models of non-model microbial species and improving WUFlux performance.Electronic supplementary materialThe online version of this article (doi:10.1186/s12859-016-1314-0) contains supplementary material, which is available to authorized users.

HPLC-based metabolomics to identify cytotoxic compounds from Plectranthus amboinicus (Lour.) Spreng against human breast cancer MCF-7Cells.

The objective of this study was to identify the active compounds in Plectranthus amboinicus (Lour.) Spreng which play a role to inhibit viability of breast cancer MCF-7 cells using HPLC-based metabolomics approach. Five fractions of the plant extract were observed including ethanol, hexane, chloroform, ethyl acetate and water fraction. There were 45 HPLC chromatograms resulted from 5 fractions with 3 replications and 3 wavelengths detection. The chromatograms were compared to the data of IC50 from MTT assay of each fraction against human breast cancer MCF-7 cells using metabolomics. The OPLS analysis result promptly pointed towards a chloroform fraction at retention time of 40.16-41.28min that has the greatest contribution to the cytotoxic activity. The data of mass spectra indicated that an abietane diterpene namely 7-acetoxy-6-hydroxyroyleanone was the main compound that contributed to the cytotoxic activity. This metabolomics application method can be used as a quick preliminary guideline to uncover the most dominant compound related to the bioactivity.

Fragmentation study of major spirosolane‐type glycoalkaloids by collision‐induced dissociation linear ion trap and infrared multiphoton dissociation Fourier transform ion cyclotron resonance mass spectrometry

Glycoalkaloids play a key role in the plant protection system against phytopathogens including fungi, viruses, bacteria, insects and worms. They can be toxic to humans if consumed in high concentrations causing gastrointestinal disturbances. The structural characterization of the major spirosolane glycoalkaloids, solasonine, solamargine, α-tomatine and dehydrotomatine, were investigated by positive electrospray ionization (ESI) coupled with a hybrid linear ion trap (LIT) and Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Tandem mass spectrometric analysis of spirosolane glycoalkaloids was performed by both collision-induced dissociation (CID) within the LIT and infrared multiphoton dissociation (IRMPD) in conjunction with the FTICR cell. Several common product ions were observed, generated by losses of the sugar moiety or aglycone fragmentation in the B- or E-ring, that can provide information on the accurate mass of aglycone and the primary sequence and branching of the oligosaccharide chains. Thanks to the multistage CID it was possible to understand the fragmentation pathways and thanks to the high resolution of IRMPD-FTICR the elemental compositions of product ions were obtained. Because the investigated tandem mass spectra data were acquired with high mass accuracy, unambiguous interpretation and determination of the chemical compositions for the majority of detected fragment ions were feasible. From these data, generalized fragmentation pathways were proposed, providing guidance for the characterization of unknown glycoalkaloids in plants. Copyright © John Wiley & Sons, Ltd.

Preliminary Study of Differentially Expressed Serum Peptides of Advanced NSCLC Patients Responsive to EGFR-TKI and Their Clinical Significance

背景与目的本研究旨在应用基质辅助激光解析离子化-时间飞行质谱仪（matrix-assisted laser desorption ionization time-of-?ight mass spectrometry, MALDI-TOF-MS）检测晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）患者在接受表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factorreceptor tyrosine kinase inhibitors, EGFR-TKIs）治疗过程中血清多肽的变化并探索其临床意义。方法收集34例接受EGFR-TKI治疗的晚期NSCLC患者TKI治疗前、最佳疗效时及疾病进展后的自身配对血清样本102份。处理血清样本并应用MALDI-TOF-MS检测，得到质谱图后使用CPT统计软件进行分析，鉴定出差异多肽，并对其临床意义进行分析。结果34例接受EGFR-TKI治疗的患者无完全缓解（complete response, CR）患者，部分缓解（partial response, PR）11例，疾病稳定（stable disease, SD）23例，中位无进展生存期（progression-free survival, PFS）为8.0个月（95%CI: 6.6-11.2）；中位总生存期（overall survival, OS）为11.4个月（95%CI: 10.6-16.5）。对TKI治疗的三个不同时间点的血清进行质谱检测，结果显示三个时间点多肽指纹图谱均不相同；配对分析最佳疗效时与基线时质谱数据经CPT软件共鉴定出差异多肽峰87个，筛选出两组间有统计学差异[P < 0.001、曲线下面积（area under curve, AUC）≥0.9]的多肽峰1个；疾病进展时与基线时共鉴定出差异多肽峰96个，筛选出两组间有统计学差异（P < 0.001, AUC≥0.9）的多肽峰3个；最佳疗效时与疾病进展时共鉴定出差异多肽峰115个，筛选出两组间有统计学差异（P < 0.001, AUC≥0.9）的多肽峰4个。结论NSCLC患者TKI治疗过程中血清多肽存在动态变化，差异多肽可能与治疗效果、疾病进展相关，差异多肽的特性、临床意义需进一步鉴定和验证。

Identification of Drugs in Parenteral Pharmaceutical Preparations from a Quality Assurance and a Diversion Program by Direct Analysis in Real-Time AccuTOFTM-Mass Spectrometry (DART-MS).

In healthcare settings drug diversion and impairment of physicians are major concerns requiring a rapid and efficient method for surveillance and detection. A Direct Analysis in Real Time ion source coupled to a JEOL AccuTOFTM time-of-flight mass spectrometer (DART-MS) method was developed to screen parenteral pharmaceutical formulations for potential drug diversion. Parenteral pharmaceutical formulations are also known as injectable formulations and are used with intravenous, subcutaneous, intramuscular and intra-articular administration. A library was created using the mass spectra data collected by a DART-MS operated in switching mode at 20, 60 and 90 V settings. This library contained 17 commonly encountered drugs in parenteral pharmaceutical formulations that included the surgical analgesic: fentanyl, hydromorphone and morphine; anesthetic: baclofen, bupivacaine, ketamine, midazolam, ropivacaine and succinylcholine; and a mixture of other drug classes: caffeine, clonidine, dexamethasone, ephedrine, heparin, methadone, oxytocin and phenylephrine. Randomly selected 200 de-identified parenteral pharmaceutical formulations containing one or more drugs were submitted for analysis to the FIRM Toxicology Laboratory at Virginia Commonwealth University Health and were screened using the DART-MS. The drug contents of the de-identified formulations were previously confirmed by a published high performance liquid chromatography (HPLC) method. The drugs in the formulations were rapidly and successfully identified using the generated library. The DART-MS and HPLC results were in complete agreement for all 200 parenteral pharmaceutical formulations.

One-pot lithium bromide-catalyzed reaction of polyoxyethylene diglycidyl ether with carbon disulfide: synthesis of new polyoxyethylene epoxyoxathiolane-2-thione

ABSTRACT A simple and highly efficient regio- and chemio-specific synthesis of polyoxyethylene epoxyoxathiolan-2-thione was realized from a one-pot reaction of polyoxyethylene diglycidyl ether and carbon disulfide using lithium bromide as a catalyst. The unsymmetrical obtained products were fully characterized by 1H, 13C NMR and high-resolution mass spectra data.

Characterization of N-methylated amino acids by GC-MS after ethyl chloroformate derivatization.

Methylation is an essential metabolic process in the biological systems, and it is significant for several biological reactions in living organisms. Methylated compounds are known to be involved in most of the bodily functions, and some of them serve as biomarkers. Theoretically, all α-amino acids can be methylated, and it is possible to encounter them in most animal/plant samples. But the analytical data, especially the mass spectral data, are available only for a few of the methylated amino acids. Thus, it is essential to generate mass spectral data and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies. In this study, all N-methyl and N,N-dimethyl amino acids were synthesized by the methylation of α-amino acids and characterized by a GC-MS method. The methylated amino acids were derivatized with ethyl chloroformate and analyzed by GC-MS under EI and methane/CI conditions. The EI mass spectra of ethyl chloroformate derivatives of N-methyl (1-18) and N,N-dimethyl amino acids (19-35) showed abundant [M-COOC2 H5 ]+ ions. The fragment ions due to loss of C2 H4 , CO2 , (CO2 + C2 H4 ) from [M-COOC2 H5 ]+ were of structure indicative for 1-18. The EI spectra of 19-35 showed less number of fragment ions when compared with those of 1-18. The side chain group (R) caused specific fragment ions characteristic to its structure. The methane/CI spectra of the studied compounds showed [M + H]+ ions to substantiate their molecular weights. The detected EI fragment ions were characteristic of the structure that made easy identification of the studied compounds, including isomeric/isobaric compounds. Fragmentation patterns of the studied compounds (1-35) were confirmed by high-resolution mass spectra data and further substantiated by the data obtained from 13 C2 -labeled glycines and N-ethoxycarbonyl methoxy esters. The method was applied to human plasma samples for the identification of amino acids and methylated amino acids. Copyright © 2016 John Wiley & Sons, Ltd.

Identification, characterization, and synthesis of process-related impurities in antiproliferative agent TQ-B3203

ABSTRACTLiposoluble camptothecin derivative, research name TQ-B3203, is a recently developed investigational antiproliferative agent by our group. The structure of TQ-B3203 is 2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate, containing an SN-38 component, a trolox component, a succinic acid linker, and a hexadecanol chain. In this study, the process-related impurities of bulk TQ-B3203 were identified, characterized, and synthesized. Seven major impurities were revealed based on the mass spectrum (MS) and nuclear magnetic resonance (NMR) spectral data. They were characterized as SN-38 (IMP-I), trolox (IMP-II), 2-(dodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-III), hexadecyl 7-ethyl-camptothecin-10-yl succinate (IMP-IV), 2-(tetradecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-V), 4-(2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VI), and 4-(2-(octodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VII). The probable origin of the impurities from the preparation process of TQ-B3203 was discussed.

Identification of photoproducts of fungicide cyprodinil and elucidation of transformation mechanism in water using LC-IT-TOF-MS/MS technique

This study aimed at investigating photodegradation of cyprodinil in aquatic solution under the simulated natural light or UV–visible irradiation (290–800 nm) using LC-MS/MS techniques. Effects of pH, nitrate ion, Fe (III), humic acid and TiO2 on photolysis kinetics of cyprodinil were explored. The photodegradation followed first-order reaction kinetics, and linear accelerating effects of Fe (III), nitrate ion and TiO2 with concentrations ranging from 0.1 to 5.0 mg L−1 on photodegradation were remarkably observed. HA at low concentration ranges (<3.0 mg L−1) enhanced cyprodinil photodegradation while the photocatalytic rate was weakened with more addition of HA. The degradation rate in alkaline solutions was greater than in acidic solutions. Six main transformation products (TPs) were separated and identified based on mass spectra data and density functional theory (DFT) quantum calculations, and their kinetic evolutions were also investigated. Ultimately, a tentative transformation mechanism was proposed based the identified TPs and their kinetic evolutions. The results indicated that one α-H on pyridine ring of cyprodinil was hydroxylated to form TPs 1. TPs 1 underwent a series of photochemical reactions involving ring-opening, addition of one H2O molecule and demethylation on three-member ring to form TPs 2, which was further hydroxylated on benzene ring to form TPs 6. TPs 3–5 were three isomers from Hofmann-Martius rearrangement of cyprodinil. These findings were of utmost importance for elucidating environmental fate of cyprodinil in aquatic ecosystem and further environmental risk evaluation.

HPLC-DAD-q-TOF-MS as a powerful platform for the determination of phenolic and other polar compounds in the edible part of mango and its by-products (peel, seed, and seed husk).

Free and bound phenolic and other polar compounds in mango edible fraction and its by-products (peel, seed, and seed husk) have been determined by HPLC-DAD-ESI-qTOF-MS. This analytical technique has demonstrated to be a valuable platform for the identification and quantification of these compounds in mango. In fact, UV-Vis and mass spectra data allowed the determination of 91 free compounds and 13 bound (cell wall linked) compounds taking into account the four fractions of mango. To our knowledge, this is the first time that mango seed husk has been studied regarding its phenolic compounds. The method proposed showed LODs between 0.006 and 0.85 μg/mL and accuracy ranged from 94.8 and 100.7%. Mango peel presented the highest concentration of free polar compounds followed by seed, pulp, and seed husk. It is also important to highlight that bound phenolic compounds had never been determined in mango pulp, seed, and seed husk before. Furthermore, ellagic acid was the most abundant bound compound in the four mango fractions analyzed. These results show that mango pulp and its by-products are a good source of phenolic and other polar compounds. In particular, mango seed contains a high total concentration of ellagic acid (650 mg/100 g dry weight).

Simultaneous qualitative and quantitative analysis of fluoroalkyl sulfonates in riverine water by liquid chromatography coupled with Orbitrap high resolution mass spectrometry

In this study, a robust method for quick screening, confirmation and quantification analysis of eight fluoroalkyl sulfonates in surface riverine samples was developed using ultra-high performance liquid chromatography-high resolution mass spectrometer (LC-Orbitrap Tribrid HRMS). Weak anion exchange solid phase extraction was optimized to maximum recover perfluoroalkyl sulfonates (PFSAs), fluorotelomer sulfonates and the emerging 6:2 chlorinated polyfluoroalkyl ether sulfonate at the same time. Both qualitative and quantitative purposes could be achieved by simultaneous acquiring full-scan mass spectrum (MS1) and data-dependent MS2 data. The LC-Orbitrap Tribrid HRMS method showed competent method detection limits for all analytes (7.1–62pg/L) compared with the triple quadrupole mass spectrometry (LC–MS/MS) quantification method (12–54pg/L), and satisfactory method validation results were also obtained in linearity (R2>0.999), trueness (88–118%), precision (2–17%) and recovery (63–103%). A good correlation (R>0.999) was found between the sets of quantified PFSA residue concentrations in thirteen estuary river samples by both the LC-Orbitrap Tribrid HRMS (0.2–440ng/L) and LC–MS/MS (0.1–424ng/L) methods, indicating that Orbitrap Tribrid HRMS could be used for reliable quantitative analysis purpose. Moreover, the LC-Orbitrap Tribrid HRMS method could also benefit from its high mass resolution characteristic to eliminate potential environment interferents (e.g., taurodeoxycholate) and to quantify all PFSA isomers based on full-scan MS1 chromatogram at a narrow MS window (5 part per million).