From the Mouse to the Mass Spectrometer:  Detection and Differentiation of the Endoproteinase Activities of Botulinum Neurotoxins A−G by Mass Spectrometry

2005 ◽  
Vol 77 (13) ◽  
pp. 3916-3924 ◽  
Author(s):  
Anne E. Boyer ◽  
Hercules Moura ◽  
Adrian R. Woolfitt ◽  
Suzanne R. Kalb ◽  
Lisa G. McWilliams ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometer ◽  
Botulinum Neurotoxins

scholarly journals Multistage Fragmentation of Ion Trap Mass Spectrometry System and Pseudo-MS3of Triple Quadrupole Mass Spectrometry Characterize Certain (E)-3-(Dimethylamino)-1-arylprop-2-en-1-ones: A Comparative Study

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ali S. Abdelhameed ◽  
Adnan A. Kadi ◽  
Hatem A. Abdel-Aziz ◽  
Rihab F. Angawi ◽  
Mohamed W. Attwa ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometer ◽  
Ion Trap ◽  
Quadrupole Mass Spectrometer ◽  
Ion Trap Mass Spectrometry ◽  
Triple Quadrupole ◽  
Quadrupole Mass ◽  
Triple Quadrupole Mass Spectrometer ◽  
Fragment Ions ◽  
Mass Spectrometry System

A new approach was recently introduced to improve the structure elucidation power of tandem mass spectrometry simulating the MS3of ion trap mass spectrometry system overcoming the different drawbacks of the latter. The fact that collision induced dissociation in the triple quadrupole mass spectrometer system provides richer fragment ions compared to those achieved in the ion trap mass spectrometer system utilizing resonance excitation. Moreover, extracting comprehensive spectra in the ion trap needs multistage fragmentation, whereas similar fragment ions may be acquired from one stage product ion scan using the triple quadrupole mass spectrometer. The new strategy was proven to enhance the qualitative performance of tandem mass spectrometry for structural elucidation of different chemical entities. In the current study we are endeavoring to prove our hypothesis of the efficiency of the new pseudo-MS3technique via its comparison with the MS3mode of ion trap mass spectrometry system. Ten pharmacologically and synthetically important (E)-3-(dimethylamino)-1-arylprop-2-en-1-ones (enaminones4a–j) were chosen as model compounds for this study. This strategy permitted rigorous identification of all fragment ions using triple quadrupole mass spectrometer with sufficient specificity. It can be used to elucidate structures of different unknown components. The data presented in this paper provide clear evidence that our new pseudo-MS3may simulate the MS3of ion trap spectrometry system.

scholarly journals 662. Identification of Clinically Relevant Microbes with the MasSpec Pen

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S386-S387
Author(s):  
Sydney C Povilaitis ◽  
Ashish D Chakraborty ◽  
Rachel D Downey ◽  
Sarmistha Bhaduri Hauger ◽  
Livia Eberlin
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometer ◽  
Model Performance ◽  
Sample Surface ◽  
Clinical Analysis ◽  
Ambient Ionization ◽  
Rapid Identification ◽  
Negative Ion ◽  
Ionization Mass ◽  
Molecular Features

Abstract Background In the age of antimicrobial resistance, rapid identification of infectious agents is critical for antimicrobial stewardship and effective therapy. To this end, ambient ionization mass spectrometry techniques have been applied for rapid identification of microbes directly from culture isolates. We have developed a handheld, mass spectrometry-based device, the MasSpec Pen, that permits direct molecular analysis of a biological sample in seconds (Scheme 1). Here, we employ the MasSpec Pen to identify clinically relevant microbes directly from culture isolates. Methods Staphylococcus aureus, Staphylococcus epidermidis, Group A and B Streptococcus, Kingella kingae (K.k), and Pseudomonas aeruginosa (P.a) were cultured on 5% sheep’s blood nutrient agar at 37 °C overnight. Colonies were transferred to a glass slide where they were analyzed directly with the MasSpec Pen coupled to a Q Exactive mass spectrometer (Thermo Scientific) in negative ion mode. For MasSpec Pen analysis, a 10 µL droplet of water was held in contact with the sample surface for 3 seconds and then aspirated to the mass spectrometer for analysis. Data was normalized and the molecular features resulting from the analysis solvent and nutrient medium were removed. The least absolute shrinkage and selection operator (lasso) statistical method was used to build classification models for prediction of bacterial identity. Model performance was evaluated by leave-one-out cross-validation and a validation set of samples. Scheme 1: MasSpec Pen workflow Results Various small molecules were detected including metabolites and glycerophospholipid species. The mass spectral profiles for each species exhibited qualitative differences among them (Figure 1). Additionally, several quorum-sensing molecules were observed in P.a. including hydroxy-heptyl-quinoline (m/z 242.155). Lasso statistical classifiers were created to differentiate organisms at the level of Gram type, genus, and species with each model comprised of a sparse set of molecular features. Accuracies of 90% or greater were achieved for all lasso models and as high as 98% for the differentiation of Staphylococcus (Staph.) and Streptococcus (Strep.). Figure 1: Molecular profiles of species analyzed Figure 2: Statistical classification results Conclusion These results demonstrate the potential of the MasSpec Pen as a tool for clinical analysis of infected biospecimens. Disclosures Sydney C. Povilaitis, BA, MS Pen Technologies, Inc. (Other Financial or Material Support, Patent) Livia Eberlin, PhD, MS Pen Technolpogies, Inc. (Board Member, Shareholder)

Application of the mass-spectrometer MASHA for mass-spectrometry and laser-spectroscopy

Laser 2009 ◽  
2010 ◽  
pp. 279-285
Author(s):  
A. M. Rodin ◽  
A. V. Belozerov ◽  
S. N. Dmitriev ◽  
Yu. Ts. Oganessian ◽  
R. N. Sagaidak ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Spectroscopy ◽  
Mass Spectrometer

scholarly journals Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH<sub>4</sub><sup>+</sup> CIMS) to oxygenated volatile organic compounds

2019 ◽  
Vol 12 (3) ◽  
pp. 1861-1870 ◽  
Author(s):  
Alexander Zaytsev ◽  
Martin Breitenlechner ◽  
Abigail R. Koss ◽  
Christopher Y. Lim ◽  
James C. Rowe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Chemical Ionization Mass Spectrometry ◽  
Collision Induced Dissociation ◽  
Ionization Mass ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic

Abstract. Chemical ionization mass spectrometry (CIMS) instruments routinely detect hundreds of oxidized organic compounds in the atmosphere. A major limitation of these instruments is the uncertainty in their sensitivity to many of the detected ions. We describe the development of a new high-resolution time-of-flight chemical ionization mass spectrometer that operates in one of two ionization modes: using either ammonium ion ligand-switching reactions such as for NH4+ CIMS or proton transfer reactions such as for proton-transfer-reaction mass spectrometer (PTR-MS). Switching between the modes can be done within 2 min. The NH4+ CIMS mode of the new instrument has sensitivities of up to 67 000 dcps ppbv−1 (duty-cycle-corrected ion counts per second per part per billion by volume) and detection limits between 1 and 60 pptv at 2σ for a 1 s integration time for numerous oxygenated volatile organic compounds. We present a mass spectrometric voltage scanning procedure based on collision-induced dissociation that allows us to determine the stability of ammonium-organic ions detected by the NH4+ CIMS instrument. Using this procedure, we can effectively constrain the sensitivity of the ammonia chemical ionization mass spectrometer to a wide range of detected oxidized volatile organic compounds for which no calibration standards exist. We demonstrate the application of this procedure by quantifying the composition of secondary organic aerosols in a series of laboratory experiments.

scholarly journals Photoproducts of the Photodynamic Therapy Agent Verteporfin Identified via Laser Interfaced Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5280
Author(s):  
Chris Furlan ◽  
Jacob A. Berenbeim ◽  
Caroline E. H. Dessent
Keyword(s):  
Mass Spectrometry ◽  
Photodynamic Therapy ◽  
Macular Degeneration ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Red Light ◽  
Solution Phase ◽  
Collision Induced Dissociation ◽  
Free Base ◽  
New Information

Verteporfin, a free base benzoporphyrin derivative monoacid ring A, is a photosensitizing drug for photodynamic therapy (PDT) used in the treatment of the wet form of macular degeneration and activated by red light of 689 nm. Here, we present the first direct study of its photofragmentation channels in the gas phase, conducted using a laser interfaced mass spectrometer across a broad photoexcitation range from 250 to 790 nm. The photofragmentation channels are compared with the collision-induced dissociation (CID) products revealing similar dissociation pathways characterized by the loss of the carboxyl and ester groups. Complementary solution-phase photolysis experiments indicate that photobleaching occurs in verteporfin in acetonitrile; a notable conclusion, as photoinduced activity in Verteporfin was not thought to occur in homogenous solvent conditions. These results provide unique new information on the thermal break-down products and photoproducts of this light-triggered drug.

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