scholarly journals Secondary organic material formed by methylglyoxal in aqueous aerosol mimics – Part 2: Product identification using Aerosol-CIMS

2009 ◽  
Vol 9 (4) ◽  
pp. 15567-15594 ◽  
Author(s):  
N. Sareen ◽  
E. L. Shapiro ◽  
A. N. Schwier ◽  
V. F. McNeill
Keyword(s):  
Ammonium Sulfate ◽  
Organic Material ◽  
Aldol Condensation ◽  
Critical Role ◽  
Negative Ion ◽  
Ionization Mass ◽  
Bulk Reaction ◽  
Product Identification ◽  
Negative Ion Mode ◽  
Sulfur Containing

Abstract. We used chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol-CIMS) to characterize secondary organic material formed by methylglyoxal with ammonium sulfate in aqueous aerosol mimics. Bulk reaction mixtures were diluted and atomized to form submicron aerosol particles. Organics were detected using Aerosol-CIMS in positive and negative ion mode using I− and H3O+·(H2O)n as reagent ions. The results are consistent with aldol condensation products, carbon-nitrogen species, sulfur-containing compounds, and oligomeric species up to 759 amu. These results support previous observations by us and others that ammonium sulfate plays a critical role in the SOA formation chemistry of dicarbonyl compounds.

scholarly journals Secondary organic material formed by methylglyoxal in aqueous aerosol mimics

2010 ◽  
Vol 10 (3) ◽  
pp. 997-1016 ◽  
Author(s):  
N. Sareen ◽  
A. N. Schwier ◽  
E. L. Shapiro ◽  
D. Mitroo ◽  
V. F. McNeill
Keyword(s):  
Organic Material ◽  
Aldol Condensation ◽  
Bimolecular Reaction ◽  
Ionization Mass ◽  
Aerosol Formation ◽  
Hydronium Ion ◽  
Rate Limiting Step ◽  
Tropospheric Aerosol ◽  
Heterogeneous Processes ◽  
Rate Limiting

Abstract. We show that methylglyoxal forms light-absorbing secondary organic material in aqueous ammonium sulfate and ammonium nitrate solutions mimicking tropospheric aerosol particles. The kinetics were characterized using UV-Vis spectrophotometry. The results suggest that the bimolecular reaction of methylglyoxal with an ammonium or hydronium ion is the rate-limiting step for the formation of light-absorbing species, with kNH4+II=5×10−6 M−1 min−1 and kH3O+II≤10−3 M−1 min−1. Evidence of aldol condensation products and oligomeric species up to 759 amu was found using chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol-CIMS). Tentative identifications of carbon-nitrogen species and a sulfur-containing compound were also made using Aerosol-CIMS. Aqueous solutions of methylglyoxal, with and without inorganic salts, exhibit significant surface tension depression. These observations add to the growing body of evidence that dicarbonyl compounds may form secondary organic material in the aerosol aqueous phase, and that secondary organic aerosol formation via heterogeneous processes may affect seed aerosol properties.

scholarly journals A binary matrix for the rapid detection and characterization of small-molecule cardiovascular drugs by MALDI-MS and MS/MS

2018 ◽  
Vol 10 (6) ◽  
pp. 572-578 ◽  
Author(s):  
Jinlan Dong ◽  
Wenjing Ning ◽  
Daniel J. Mans ◽  
Jamie D. Mans
Keyword(s):  
Small Molecule ◽  
Hydroxycinnamic Acid ◽  
Cardiovascular Drugs ◽  
Maldi Ms ◽  
Negative Ion ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Binary Matrix ◽  
Negative Ion Mode

A mixture of α-cyano-4-hydroxycinnamic acid and 1,5-diaminonaphthalene was discovered as a novel binary matrix for the qualitative analysis of 14 small-molecule (∼250–550 Da) cardiovascular drugs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and MS/MS in either positive or negative ion mode.

Unexpected cytosine–AuCl4− interaction under electrospray ionization mass spectrometry conditions—Formation of cytosine–Au(I) complexes

2019 ◽  
Vol 26 (3) ◽  
pp. 225-229
Author(s):  
Magdalena Frańska ◽  
Emilia Konował
Keyword(s):  
Electrospray Ionization ◽  
Gas Phase ◽  
Mass Spectra ◽  
Mass Spectrometric ◽  
Negative Ion ◽  
Ionization Mass ◽  
Ionization Source ◽  
Full Scan ◽  
Negative Ion Mode ◽  
Product Ion Spectra

The interaction of cytosine with AuCl4−, under electrospray ionization mass spectrometric conditions, is discussed. On the basis of respective full scan mass spectra and product ion spectra, obtained in positive and negative ion mode, it has been deduced that cytosine is very prone to form Au(I)-containing complexes. The complexes may be formed in the gas phase by decomposition of Au(III)-containing complexes and also in the electrospray ionization source as a result of the occurrence of redox process. It has also been found that the interaction of cytosine with Au+ is stronger than that with Cu+ or Ag+, although taking into account the electrostatic attraction, it is not expected.

1,5-Diaminonaphthalene functionalized carbon nanodots as a novel matrix for the analysis of small molecules by matrix-assisted laser desorption/ionization mass spectrometry

2019 ◽  
Vol 11 (8) ◽  
pp. 1131-1136 ◽  
Author(s):  
Yueying Zhang ◽  
Dan Gao ◽  
Shangfu Li ◽  
Weili Wei ◽  
Jinshun Lin ◽  
...  
Keyword(s):  
Small Molecules ◽  
Direct Detection ◽  
Laser Desorption ◽  
Negative Ion ◽  
Carbon Nanodots ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Negative Ion Mode ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

1,5-Diaminonaphthalene functionalized carbon nanodots (DAN-CDs) were explored as a matrix for direct detection of small molecules by MALDI-MS in negative-ion mode.

scholarly journals Characterization of oligomers from methylglyoxal under dark conditions: a pathway to produce secondary organic aerosol through cloud processing during nighttime

2010 ◽  
Vol 10 (8) ◽  
pp. 3803-3812 ◽  
Author(s):  
F. Yasmeen ◽  
N. Sauret ◽  
J.-F. Gal ◽  
P.-C. Maria ◽  
L. Massi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosol ◽  
Aldol Condensation ◽  
Organic Aerosol ◽  
Negative Ion ◽  
Hydroxy Ketone ◽  
Oh Radicals ◽  
Ionization Mass ◽  
Acid Catalyzed ◽  
Dark Conditions

Abstract. Aqueous-phase oligomer formation from methylglyoxal, a major atmospheric photooxidation product, has been investigated in a simulated cloud matrix under dark conditions. The aim of this study was to explore an additional pathway producing secondary organic aerosol (SOA) through cloud processes without participation of photochemistry during nighttime. Indeed, atmospheric models still underestimate SOA formation, as field measurements have revealed more SOA than predicted. Soluble oligomers (n = 1–8) formed in the course of acid-catalyzed aldol condensation and acid-catalyzed hydration followed by acetal formation have been detected and characterized by positive and negative ion electrospray ionization mass spectrometry. Aldol condensation proved to be a favorable mechanism under simulated cloud conditions, while hydration/acetal formation was found to strongly depend on the pH of the system and only occurred at a pH<3.5. No evidence was found for formation of organosulfates. The aldol oligomer series starts with a β-hydroxy ketone via aldol condensation, where oligomers are formed by multiple additions of C3H4O2 units (72 Da) to the parent β-hydroxy ketone. Ion trap mass spectrometry experiments were performed to structurally characterize the major oligomer species. A mechanistic pathway for the growth of oligomers under cloud conditions and in the absence of UV-light and OH radicals, which could substantially enhance in-cloud SOA yields, is proposed here for the first time.

scholarly journals Dimerization of Peptides by Calcium Ions: Investigation of a Calcium-Binding Motif

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Azadeh Jamalian ◽  
Evert-Jan Sneekes ◽  
Lennard J. M. Dekker ◽  
Mario Ursem ◽  
Theo M. Luider ◽  
...  
Keyword(s):  
Calcium Ions ◽  
Calcium Binding ◽  
Kinetic Method ◽  
Negative Ion ◽  
Binding Motif ◽  
Ionization Mass ◽  
Binding Motifs ◽  
Calcium Affinity ◽  
Active Calcium ◽  
Negative Ion Mode

We investigated calcium-binding motifs of peptides and their recognition of active functionalities for coordination. This investigation generates the fundamentals to design carrier material for calcium-bound peptide-peptide interactions. Interactions of different peptides with active calcium domains were investigated. Evaluation of selectivity was performed by electrospray ionization mass spectrometry by infusing solutions containing two different peptides (P1 and P2) in the presence of calcium ions. In addition to signals for monomer species, intense dimer signals are observed for the heterodimer ions (P1⋯Ca2+⋯P2) (⋯ represents the noncovalent binding of calcium with the peptide) in the positive ion mode and for ions (P1-2H2-⋯Ca2+⋯P2-2H2-) in the negative ion mode. Monitoring of the dissociation from these mass selected dimer ions via the kinetic method provides information on the calcium affinity order of different peptide sequences.

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