Kevin J James

University College Cork, Corcaigh, Munster, Ireland

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Publications (104)268.49 Total impact

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    Full-text · Dataset · Jul 2015
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    ABSTRACT: Tomatoes, members of the Solanaceae plant family, produce biologically active secondary metabolites, including glycoalkaloids, which may have both adverse and beneficial biological effects. Using the linear ion trap (LIT) mass spectrometry, multi-stage collision induced dissociation (CID) experiments (MSII) were performed to elucidate characteristic fragmentation pathways of the glycoalkaloid, tomatidine and of beta(1)-hydroxytomatine. High resolution with high accuracy mass analysis using an Orbitrap fourier transform MS with higher-energy collisional induced dissociation (HCD) was used to produce mass spectra data across a wide spectral range for confirmation of proposed ion structures and formulae.
    No preview · Article · Apr 2015 · Natural product communications
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    ABSTRACT: Tomatoes, members of the Solanaceae plant family, produce biologically active secondary metabolites, including glycoalkaloids, which may have both adverse and beneficial biological effects. Using the linear ion trap (LIT) mass spectrometry, multi-stage collision induced dissociation (CID) experiments (MSn) were performed to elucidate characteristic fragmentation pathways of the glycoalkaloid, tomatidine and of β1-hydroxytomatine. High resolution with high accuracy mass analysis using an Orbitrap fourier transform MS with higher-energy collisional induced dissociation (HCD) was used to produce mass spectra data across a wide spectral range for confirmation of proposed ion structures and formulae.
    Full-text · Article · Apr 2015 · Natural product communications
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    ABSTRACT: Isoflavones and coumestranes are the most important classes of compounds among phytoestrogens; by binding to estrogen receptors, they mimic or modulate the effect on the endogenous receptors. Little information can be found in literature about the presence of isoflavones and coumestrol in the environment, even if it is known that this may have significance, being these substances classified as endocrine disrupting compounds. In this research, we aim to explore the capabilities of the LTQ Orbitrap Discovery hybrid MS in full-scan acquisition mode, with high resolution, to validate an analytical method for the quantification of nine isoflavones (genistein, genistin, glycitein, daidzein, daidzin, (R,S)-equol, biochanin A, formononetin and coumestrol) in wastewater samples. The correlation coefficients of calibration curves of the nine analyzed compounds were in a range of 0.996–0.999; recoveries at two different levels of concentration (0.05 and 0.5 µg/l) were in the range 73–98%, and the limits of detection ranged between 0.0014 and 0.017 µg/l, proving that this method is sensitive enough in comparison with other methods available in literature. This method has been applied for the analysis of 20 wastewater treatment plants in County Cork, Ireland. Copyright © 2015 John Wiley & Sons, Ltd.
    Full-text · Article · Jan 2015 · Journal of Mass Spectrometry
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    ABSTRACT: Liquid chromatography multiple tandem mass spectrometry (LC-MS/MS) has been applied to demonstrate that azaspiracid (AZA1), its isomer, AZA6, and its methyl- and demethyl-analogues, AZA2 and AZA3 respectively, are distributed throughout mussel (Mytilus edulis) tissue compartments. Large differences in both the toxin content and the toxin profiles were observed in 20 individual mussels from the same batch. The toxin levels found in the hepatopancreas of mussels were, AZA1 (0.02-5.0 μg/g); AZA2 (0.12-1.9 μg/g), AZA3 (0.06-0.88 μg/g) and AZA6 (0.05-2.0 μg/g). This study also examined the toxin content in mussel tissue compartments and it was found that the gills contributed significantly to the overall level of toxins in mussels. Although polyether toxins are usually concentrated in the hepatopancreas of shellfish this is not always the situation with azaspiracids. The mean distribution of azaspiracids in mussels was; hepatopancreas (60.6%), gills (12.0%) and adductor muscle (27.4%).
    No preview · Article · Dec 2014 · Toxicon
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    Giovanni Caprioli · Michael G. Cahill · Kevin J. James
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    ABSTRACT: Tomatoes, members of the Solanaceae plant family, produce biologically active secondary metabolites, including glycoalkaloids, which may have both adverse and beneficial biological effects. By using the linear ion trap (LIT) mass spectrometry, multistage collision-induced dissociation (CID) experiments (MSn ) were performed to elucidate characteristic fragmentation pathways of the glycoalkaloid α-tomatine. High-resolution with high-accuracy mass analysis using an Orbitrap Fourier transform MS (FTMS) with higher-energy CID (HCD) was used to produce mass spectra data across a wide spectral range for confirmation of proposed ion structures and formulae. In addition, a new liquid chromatography method that utilized LTQ Orbitrap MS was developed for the analysis of α-tomatine in tomatoes. Recoveries of α-tomatine were >96.0 % with relative standard deviations (RSD) below 7.98 %. The limit of detection (LOD) was 0.002 mg/kg. The limit of quantitation (LOQ) was 0.005 mg/kg. The linear range was between 0.010 and 10 mg/kg with an excellent correlation coefficient (R 2) ≥ 0.9991. Various tomato samples were analyzed for method application, and the level of α-tomatine in the 11 samples analyzed ranged from 0.0011to 0.3077 mg/kg.
    Full-text · Article · Sep 2014 · Food Analytical Methods
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    ABSTRACT: The fate of natural toxins in the environment has been in focus for the past years. Also, plant produced compounds that can be introduced to the environment by processes such as leaching, decomposition of plant residues or root exudation. The two toxic glycoalkaloids (alpha-solanine and alpha-chaconine) and theirs aglycons (demissidine and solasodine) produced by the potato plant (Solanum Tuberosum L.) have been found in upper soil collected each week in two months in varying levels. A new analytical method that uses liquid chromatography Orbitrap mass spectrometry has been developed for the analysis of two glycoalkaloids and two aglycons in potato upper soils, and method validation was performed including sensitivity, recovery, linearity, accuracy and precision and specificity. The application of this method for routine screening of these compounds has been achieved and this study represents a simple, fast and reliable method for the quantification of these compounds in potato upper soils.
    Full-text · Article · Sep 2014 · Journal of the Brazilian Chemical Society
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    ABSTRACT: Abstract Tomatoes, members of the Solanaceae plant family, produce biologically active secondary metabolites, including glycoalkaloids and aglycons, which may have both adverse and beneficial biological effects. A new liquid chromatography method that utilized LTQ-Orbitrap MS was developed for the analysis of tomatidine, the main aglycon in tomatoes. Recoveries of tomatidine were >98.3% with the relative standard deviations (RSDs) below 6.1%. The limit of detection (LODs) was 0.0003 mg kg(-1). The limit of quantitation (LOQs) is 0.001 mg kg(-1). The linear range was between with 0.0025 and 1 mg kg(-1) with an excellent correlation coefficient (R(2)) equal to 0.9990. Various tomato samples were analyzed and the level of tomatidine in the 11 samples analysed was higher in normal respect to organic tomatoes. The capability of the set-up Full Scan LTQ-Orbitrap MS method allowed us to quantified two non-target analytes. The m/z 1032 was identified as dehydrotomatine, confirmed through accurate mass studies (mass error in ppm equal to 1.5017) meanwhile m/z 902 as (Glc)2-Gal-Tomatidine (β1-Tomatine) (mass error in ppm equal to 2.0719).
    Full-text · Article · Aug 2014 · International Journal of Food Sciences and Nutrition
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    ABSTRACT: Potatoes produce biologically active secondary metabolites like glycoalkaloids and their aglycons, which may have both adverse and beneficial effects in the diet. A new analytical method that uses liquid chromatography–mass spectrometry (LTQ-Orbitrap) has been developed for the analysis of glycoalkaloids and their aglycons in potato samples. Two glycoalkaloids, α-solanine and α-chaconine, and two aglycons, demissidine and solasodine, were quantified in potato samples. Samples were extracted using methanol, purified on an SPE Strata C18 cartridge, and then analyzed in HPLC–mass spectrometry (LTQ-Orbitrap) with the FTMS operating in full scan at a resolving power of 30,000 (FWHM), enabling the detection and accurate mass measurement and with the ITMS mode operating in MRM (multiple reaction monitoring) for glycoalkaloids and their aglycons using the [M + H]+ ions and their optimized collision energies. After validation, the method was applied to screen different type of potatoes, and some cooking experiment were conducted.
    Full-text · Article · Aug 2014 · Food Analytical Methods
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    ABSTRACT: Acidic pesticide and pharmaceutical contaminants were pre-concentrated and extracted from wastewater samples (500mL) using solid-phase extraction. Analyte recoveries were 79-96%, with % RSD values in the range, 1.7-7.4%. Analyte identification and quantification were carried out using liquid chromatography-mass spectrometry (LC-MS) with hybrid linear ion trap (LIT) Orbitrap instrumentation. Using a resolution setting of 30,000 FWHM, full-scan MS analysis was performed using heated electrospray ionization (HESI) in negative mode. The high mass resolution capabilities of the Orbitrap MS were exploited for the determination of trace contaminants allowing facile discrimination between analytes and matrix. The dependant scan functions of the Orbitrap MS using higher collisional dissociation (HCD) and LIT MS were evaluated for the confirmation of analytes at trace concentration levels. Mass accuracy for target contaminants using this method was less than 2ppm. The limits of quantitation (LOQs) were in the range, 2.1-27ng/L. The inter-day accuracy and precision were measured over a five-day period at two concentrations. The % relative errors were in the range, 0.30-7.7%, and the % RSD values were in the range, 1.5-5.5%. Using this method, 2,4-D, mecoprop, ibuprofen, naproxene and gemfibrozil were identified in several wastewater treatment plants in Ireland.
    No preview · Article · Oct 2012 · Journal of Chromatography A
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    ABSTRACT: Most of the liquid chromatography/mass spectrometry (LC/MS) methods that have been developed for the analysis of Diarrhetic Shellfish Poisoning (DSP) toxins in shellfish and algae samples have been unable to differentiate the isomers okadaic acid (OA) and dinophysistoxin-2 (DTX2), unless separated by chromatography. Since there are many bioconversion products of these compounds it is imperative to determine characteristic product ions, which can provide unequivocal identification of OA and DTX2 and their analogs. Using electrospray ionization, the fragmentation processes for two types of precursor ions, [M+Na](+) and [M-H](-), of the polyether marine toxins, dinophysistoxins (DTXs), were studied using a hybrid linear ion trap Orbitrap mass spectrometer which provided high mass accuracy data in combination with multiple tandem mass (MS(n)) spectra. Three structurally related toxins were compared; okadaic acid (OA), dinophysistoxin-2 (DTX2) and dinophysistoxin-1 (DTX1). A quick multiple reaction monitoring (MRM) LC/MS/MS method was developed utilizing the characteristic precursor/product ion mass transitions. Comparison of the high-resolution product ion, [M-H](-), spectra of these toxins featured dominant signals that resulted from two six-centered rearrangements and previously proposed fragmentation pathways for the ion of m/z 321 and 293 have been corrected and identified. By contrast, the [M+Na](+) product ion spectra only revealed distinctive ions for the isomers, OA (m/z 595, 443 and 151) and DTX2 (m/z 581, 429 and 165). To illustrate the benefits of this study, a mass selective LC/MS/MS method was developed in which the isomers OA and DTX2 co-eluted but were distinguished using the mass transitions, m/z 827/595, 827/443 (OA) and m/z 827/581, 827/429 (DTX2). Comparison of OA, DTX2 and DTX1 led to the correction of proposed negative ion mode fragmentation pathways. Through extensive study and comparison of the [M+Na](+) product ion spectra, distinctive product ions were identified which allowed for these compounds to be identified and distinguished without separation for the first time.
    No preview · Article · Aug 2012 · Rapid Communications in Mass Spectrometry
  • Josep Rubert · Kevin J James · Jordi Mañes · Carla Soler
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    ABSTRACT: The aim of this study was to evaluate the applicability of different calibration approaches in trichothecenes analysis from wheat flour. Concretely eight trichothecenes (five type B trichothecenes and three type A trichothecenes) were analyzed by matrix solid-phase dispersion (MSPD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the first set of experiments the presence of matrix effects was evaluated; values ranged between 59% and 79%. In the second set of experiments, solutions to compensate these signal suppressions were examined. Different calibration methods showed to tackle matrix effects obtaining values between 69% and 85% for external matrix matched calibration and values from 76% to 111% and from 78% to 108% by analog and deuterated internal standard calibrations, respectively. Trueness of the method was studied using quality control material and certificated reference material (DON 1062 ± 110 μg kg(-1)). The values were compared by matrix-matched, analog internal standard (deepoxydeoxynivalenol (DOM-1)) and deuterated internal standard (DON-d(1)).
    No preview · Article · Mar 2012 · Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association
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    Josep Rubert · Kevin J James · Jordi Mañes · Carla Soler
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    ABSTRACT: Recent developments in mass spectrometers have created a paradoxical situation; different mass spectrometers are available, each of them with their specific strengths and drawbacks. Hybrid instruments try to unify several advantages in one instrument. In this study two of wide-used hybrid instruments were compared: hybrid quadrupole-linear ion trap-mass spectrometry (QTRAP®) and the hybrid linear ion trap-high resolution mass spectrometry (LTQ-Orbitrap®). Both instruments were applied to detect the presence of 18 selected mycotoxins in baby food. Analytical parameters were validated according to 2002/657/CE. Limits of quantification (LOQs) obtained by QTRAP® instrument ranged from 0.45 to 45 μg kg⁻¹ while lower limits of quantification (LLOQs) values were obtained by LTQ-Orbitrap®: 7-70 μg kg⁻¹. The correlation coefficients (r) in both cases were upper than 0.989. These values highlighted that both instruments were complementary for the analysis of mycotoxin in baby food; while QTRAP® reached best sensitivity and selectivity, LTQ-Orbitrap® allowed the identification of non-target and unknowns compounds.
    Full-text · Article · Feb 2012 · Journal of Chromatography A
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    Josep Rubert · J Mañes · Kevin J. James · Carla Soler
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    ABSTRACT: This paper reports the application of liquid chromatography electrospray ionization ion trap-orbitrap mass spectrometry for the determination of 18 mycotoxins (aflatoxins, fumonisins, trichothecenes, ochratoxin A, sterogmatocystin, beauvaricin, zearalenone and zearalenol) in beer. The extraction procedure was carried out by solid phase extraction (SPE): SPE columns were conditioned with acetonitrile/methanol and water. Beer was loaded onto the column which was washed with water. In these conditions, the recoveries were more than 65% and the relative standard deviation (RSD) were below 18%. The lowest limits of quantification (LLOQ) ranged from 9 to 155 ng ml(-1). Matrix-matched calibration was performed for each beer and reliable results were obtained from selected mycotoxins. The method was applied to the analysis of 25 commercial beers. Taking advantage of the hybrid capabilities, the presence of other mycotoxins were checked; enniatins (A, A(1), B and B(1)) and fusaproliferin were studied in all the tested samples. The survey detected the presence of zearalenone in one stout beer sample.
    Full-text · Article · Jun 2011 · Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment
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    ABSTRACT: Azaspiracid Poisoning (AZP) is a human toxic syndrome which is associated with the consumption of bivalve shellfish. Unlike other shellfish, mussels contain a large array of azaspiracid analogs, many of which are suspected bioconversion products. These studies were conducted to elucidate the metabolic pathways of azaspiracid (AZA1) in the blue mussel (Mytilus edulis) and revealed that the main biotransformation product was the more toxic demethyl analog, AZA3. To elucidate the mechanism of this C-demethylation, an unprecedented xenobiotic bioconversion step in shellfish, AZA1 was fed to mussels that contained no detectable azaspiracids. Triple quadrupole mass spectrometry (MS) and high resolution Orbitrap MS were used to determine the uptake of AZA1 and the toxin profiles in three tissue compartments of mussels. The second most abundant bioconversion product was identified as AZA17, a carboxyl analog of AZA3, which is a key intermediate in the formation of AZA3. Also, two pairs of isomeric hydroxyl analogs, AZA4/AZA5 and AZA7/AZA8, have been confirmed as bioconversion products for the first time. Ultra high resolution (100 k) MS studies showed that the most probable structural assignment for AZA17 is 22-carboxy-AZA3 and a mechanism for its facile decarboxylation to form AZA3 has been proposed.
    No preview · Article · Mar 2011 · Environmental Science & Technology
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    ABSTRACT: Effluent from wastewater treatment plants have been identified as an important source of micro-organic contaminants in the environment. An online high-performance liquid chromatography–heated electrospray ionization tandem mass spectrometric method was developed and validated for the determination of basic pesticides in effluent wastewaters. Most available methods for pesticide analysis of wastewater samples are time-consuming, require complex clean-up steps and are difficult to automate. The method developed used a simple solid-phase extraction clean-up for salt and lipid reduction. On-line sample pre-concentration was performed using a reversed phase (C18) column, and analytes were separated by back-flushing onto an analytical column (C8) with detection using QqQ MS. An option to increase MS resolution was exploited to minimize interference from endogenous compounds in the matrix. A better than unit mass resolution was used (Q1 full width half maximum (FWHM) = 0.2 Da and Q3 FWHM = 0.7 Da), which was as rugged as a unit resolution method, and improved signal/noise and better detection limits were achieved for the targeted basic pesticides. This method was applied to the determination of 11 pesticides, including methoxytriazine, chlorotriazines, chloroacetanilides, phenylurea and carbamate pesticides. The percentage recovery values for these pesticides using the online trapping column were within the range, 73–95%, with relative standard deviation (RSD) values <8.9%. The highest concentrations of these pesticides in wastewater effluents in County Cork, Ireland, were simazine (0.51 μg/L), prometon (0.14 μg/L), diuron (0.21 μg/L) and atrazine (0.19 μg/L). Online Abstract Figure Effect of mass resolution change on signal/noise in the ion chromatograms for simazine at a) resolution setting, FWHM = 0.6 Da, b) resolution setting, FWHM = 0.2 Da.
    Full-text · Article · Feb 2011 · Analytical and Bioanalytical Chemistry
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    No preview · Article · Dec 2010 · ChemInform
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    ABSTRACT: The biotoxins, azaspiracids (AZAs), from marine phytoplankton accumulate in shellfish and affect human health by causing severe gastrointestinal disturbance, diarrhea, nausea and vomiting. Specific and sensitive methods have been developed and validated for the determination of the most commonly occurring azaspiracid analogs. An LTQ Orbitrap mass spectrometer is a hybrid instrument that combines linear ion trap (LIT) mass spectrometry (MS) with high-resolution Fourier transform (FT) MS and this was exploited to perform simultaneous ultra-high-resolution full-scan MS analysis and collision-induced dissociation (CID) tandem mass spectrometry (MS/MS). Using the highest mass resolution setting (100 000 FWHM) in full-scan mode, the methodology was validated for the determination of six AZAs in mussel (Mytilus galloprovincialis) tissue extracts. Ultra-high mass resolution, together with a narrow mass tolerance window of ±2 mDa, dramatically improved detection sensitivity. In addition to employing chromatographic resolution to distinguish between the isomeric azaspiracid analogs, AZA1/AZA6 and AZA4/AZA5, higher energy collisionally induced dissociation (HCD) fragmentation on selected precursor ions were performed in parallel with full-scan FTMS. Using HCD MS/MS, most precursor and product ion masses were determined within 1 ppm of the theoretical m/z values throughout the mass spectral range and this enhanced the reliability of analyte identity. For the analysis of mussels (M. galloprovincialis), the method limit of quantitation (LOQ) was 0.010 µg/g using full-scan FTMS and this was comparable with the LOQ (0.007 µg/g) using CID MS/MS. The repeatability data were; intra-day RSD% (1.8–4.4%; n = 6) and inter-day RSD% (4.7–8.6%; n = 3). Application of these methods to the analysis of mussels (M. edulis) that were naturally contaminated with azaspiracids, using high-resolution full-scan Orbitrap MS and low-resolution CID MS/MS, produced equivalent quantitative data. Copyright
    No preview · Article · Oct 2010 · Rapid Communications in Mass Spectrometry
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    ABSTRACT: The azaspiracids are a family of lipophilic polyether marine biotoxins that have caused a number of human intoxication incidents in Europe since 1995 after consumption of contaminated shellfish (Mytilus edulis). Levels of azaspiracids in shellfish for human consumption are monitored in accordance with EU guidelines: only shellfish with less than 160 microg kg(-1) are deemed safe. The limited availability of commercially available standards for azaspiracids is a serious problem, because validated LC-MS methods are required for routine analysis of these toxins in shellfish tissues. The procedure described herein has been used for the separation and the isolation of four azaspiracid (AZA) toxins from shellfish, for use as LC-MS-MS reference materials. Five separation steps have been used to isolate azaspiracids 1, 2, 3, and 6. The purity of the toxins obtained has been confirmed by multiple mass spectrometric methods using authentic azaspiracid standards. The same techniques have been used for quantification of the toxins extracted. The isolation procedure involves several chromatographic purification techniques: solid-phase extraction (diol sorbent, 90% mass reduction, and 95 +/- 1% toxin recovery); Sephadex size-exclusion chromatography (87% mass reduction and up to 95 +/- 2% toxin recovery), Toyopearl HW size-exclusion chromatography (90% mass reduction and up to 92.5 +/- 2.5% toxin recovery), and semi-preparative LC (78 +/- 3% toxin recovery). The procedure effectively separates the toxins from the sample matrix and furnishes azaspiracid toxins (AZA1, AZA2, AZA3 and AZA6) of sufficient purity with an average yield of 65% (n = 5). Triple-quadrupole mass spectrometry was used for qualitative and quantitative monitoring of the isolation efficiency after each stage of the process. High-resolution mass spectrometric evaluation of the toxic isolated material in both positive and negative modes suggests high purity.
    No preview · Article · Oct 2010 · Analytical and Bioanalytical Chemistry
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    ABSTRACT: The mass fragmentation of potato glycoalkaloids, α-solanine and α-chaconine, and the aglycons, demissidine and solasodine were studied using the Orbitrap Fourier transform (FT) mass spectrometer. Using the linear ion trap (LIT) mass spectrometry, multistage collisional-induced dissociation (CID) experiments (MS(n)) on the [M + H](+) precursor ions were performed to aid the elucidation of the mass fragmentation pathways. In addition, higher energy collisional-induced dissociation (HCD) mass spectra were generated for these toxins at a high resolution setting [100,000 FWHM (full width at half maximum)] using the Orbitrap. This hybrid mass spectrometry instrumentation was exploited to produce MS(3) spectra by selecting MS(2) product ions, generated using LIT MS, and fragmentation using HCD. The accurate mass data in the MS(3) spectra aided the confirmation of proposed product ion formulae. The precursor and product ions from glycoalkaloids lost up to four sugars from different regions during MS(n) experiments. Mass fragmentation of the six-ring aglycons were similar, generating major product ions that resulted from cleavages at the B-rings and E-rings.
    Full-text · Article · Sep 2010 · Journal of Mass Spectrometry

Publication Stats

4k Citations
268.49 Total Impact Points

Institutions

  • 2011-2015
    • University College Cork
      • Environmental Research Institute
      Corcaigh, Munster, Ireland
  • 1997-2012
    • Cork Institute of Technology
      • Department of Chemistry
      Corcaigh, Munster, Ireland
  • 1998-2010
    • Tohoku University
      Japan
  • 2007
    • University of Valencia
      • Laboratori de Bromatologia i Toxicologia
      Burjassot, Valencia, Spain