Mass Spectrometry

Burlingame, Alma L.; Boyd, Robert K.; Gaskell, Simon J.

doi:10.1021/a1960021u

Cited by 185 publications

(89 citation statements)

References 597 publications

(18 reference statements)

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“…Its introduction in close vicinity to other basic amino acids will not increase the maximum charge state to the level estimated by counting the number of basic sites. This was nicely demonstrated by Downard and Biemann for the peptide series, G 6 , (RG) 3 and R 6 , where the maximum charge state increases from 1 to 3 to 4, and hence on average only 65% of the arginine residues are protonated in R 6 . 17 The situation at the N-terminus is even more interesting as there is already a positive charge present.…”

Section: Discussionsupporting

confidence: 56%

“…3 These compounds are efficiently ionized by the electrospray process which produces a characteristic distribution of multiply charged molecular ions (envelope) within a limited range of mass-to-charge (m/z) ratios, typically between m/z 300 and m/z 2,000, irrespective of the analyte molecular weight. 4 This multiple charging phenomenon is an intrinsic feature of the electrospray ionization process, and permits high mass measurements on virtually any type of mass spectrometer.…”

Section: Introductionmentioning

confidence: 99%

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Average and maximum charge states of arginine-containing dendrimer-like peptide ions formed by electrospray ionization

Schulze

Heukeshoven

1998

Eur. J. Mass Spectrom.

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The maximum and average charge states formed by electrospray ionization of dendrimer-like multiple antigenic peptides (MAPs) which differ in structure only in the presence of an arginine residue at the N-termini of their four peptide chains have been investigated. Stepwise addition of arginine residues leads to increased charging. It has been found that the average charge state is linearly correlated to the number of arginine residues which allows the conclusion that the four peptide chains are effectively independent. The average charge state z av is shifted with each added arginine residue by roughly 0.3 units towards lower m/z ratios. Modification of the alpha-amino groups by acetylation reduces z av as compared with the corresponding non-modified model peptides. This suggests that the N-terminal arginine is to some extent protonated on both its alpha-amino group and its side-chain guanidino group. The Coulomb repulsion is presumably reduced through intramolecular charge solvation in the N-terminal part of the peptide chains.

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Section: Discussionsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Average and maximum charge states of arginine-containing dendrimer-like peptide ions formed by electrospray ionization

Schulze

Heukeshoven

1998

Eur. J. Mass Spectrom.

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“…[3][4][5][6][7][8][9][10] On the other hand, because of the complexity of a real sample, the chromatographic separation of the target metallic element species was usually necessary for its speciation. [11][12][13][14][15] In this study, the interaction of lanthanum with ethylenediamine tetraacetic acid (EDTA), which has donor atoms of nitrogen and oxygen, and may be considered as a model ligand existing in the environment, and with Ltryptophen (Try) as the basic unit of a protein, were studied by the cation-exchange HPLC coupled with ESI-MS. The stability of La species during a cation-exchange chromatographic separation process is also discussed in this paper for obtaining accurate information on lanthanum speciation.…”

mentioning

confidence: 99%

Evaluation of Dissolved Species of Lanthanum in the Solutions Containing Different Amino Acids by Cation-Exchange Chromatography Coupled with Electrospray Ionization Mass Spectrometry

et al. 2000

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Because the separation and purification methods of rare-earth elements (REEs) are well developed, REEs have recently been widely used in many fields of industry and agriculture. The widespread application of REEs as additives in fertilizers, especially in China, 1 inherently leads to their residues in the environment, accumulation in organisms, and entering into the food chain. Moreover, the bioavailability and toxicity of REEs mainly depend on its dissolved species, which can be partly assimilated by plants and animals. Thus, the speciation analysis of REEs in the environment and organisms is becoming ever more important today. The study of the interaction of REEs with humic substances and proteins is a useful way to understand their behavior in the environment or during the biological process of an organism.Electrospray ionization (ESI), as a soft source for mass spectrometry (MS), has recently been used to evaluate the chemical species of dissolved metal ions; it provides information on the interaction between metal ions and organic ligands, which forms the basis of many essential biochemical processes. [3][4][5][6][7][8][9][10] On the other hand, because of the complexity of a real sample, the chromatographic separation of the target metallic element species was usually necessary for its speciation. [11][12][13][14][15] In this study, the interaction of lanthanum with ethylenediamine tetraacetic acid (EDTA), which has donor atoms of nitrogen and oxygen, and may be considered as a model ligand existing in the environment, and with Ltryptophen (Try) as the basic unit of a protein, were studied by the cation-exchange HPLC coupled with ESI-MS. The stability of La species during a cation-exchange chromatographic separation process is also discussed in this paper for obtaining accurate information on lanthanum speciation. Experimental Reagents and chemicalsLanthanum oxide (La2O3) was obtained from Changchun Institute of Applied Chemistry of the Chinese Academy of Sciences; purity >99.9999%. La stock solution (1.00 mg cm -3 ) was prepared by dissolving an appropriate amount of La2O3, which had been ignited at 850˚C for 4 h, in 2 mol dm -3 HNO3, and then diluted with doubly deionized Milli-Q water to 100 mL in a polyethylene bottle. Ligand stock solutions (5×10 -3 mol dm -3 ) were prepared by dissolving EDTA-Na2 (A. R., Shanghai Reagent Factory) with doubly deionized Milli-Q water, and Try (purity >99%, Shanghai Bo-Ao Bio-Technology Co.) with a 1:1 water-methanol solution in acid-washed polyethylene bottles. HPLC-grade methanol was obtained from Shanghai Wusong Chemical Factory. An ammonium acetate-acetic acid (A. R., Shanghai Reagent Factory) solution (1×10 -3 mol dm -3 , pH 5 -6) was used as a buffer. Formic acid (A. R., Shanghai Reagent Factory) and α-hydroxyisobutyric acid (α-HIBA, Hunan Institute of Rare-earth Metals of China, A. R.) solutions were used as mobile phases for HPLC separation. Samples were prepared by combining the calculated amount of stock and buffer solutions to give an La concentration of 1×10...

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“…[1][2][3][4][5] MALDI is achieved in two steps. [6][7][8][9] In the first step, a mixture solution of an analyte and a matrix is spotted on the sample plate, and is dried before analysis. A solid solution deposit of analyte-doped matrix crystals is obtained, and the analyte molecules are completely isolated from each other by embedding throughout the matrix.…”

mentioning

confidence: 99%

Role of a UV Absorber as a Matrix for Analysis of Polystyrene Using Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry

Choi¹,

Chung²

2012

Bulletin of the Korean Chemical Society

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Matrix-assisted laser desorption/ionization (MALDI) has been widely used as a soft ionization technique and matrixassisted laser desorption/ionization-mass spectrometry (MALDI-MS) has been used to characterize polymeric materials.1-5 MALDI is achieved in two steps. [6][7][8][9] In the first step, a mixture solution of an analyte and a matrix is spotted on the sample plate, and is dried before analysis. A solid solution deposit of analyte-doped matrix crystals is obtained, and the analyte molecules are completely isolated from each other by embedding throughout the matrix. The second step involves ablation of the solid solution by pulse laser. The pulse laser irradiation induces rapid heating to cause sublimation of the matrix crystals and ionization can occur during this process. Selection of the matrix in MALDI-MS absolutely affect the MALDI process. 1,2o-Hydroxyphenyl benzotriazole and hydroxyphenyl triazine derivatives are commonly used as UV absorbers. They absorb destructive UV radiation and dissipate the energy in the form of heat.9-15 In general, the UV absorbers absorb UV wavelength between 295 and 400 nm, so they can potentially play a role as a matrix in MALDI analysis. 16,17 In this study, the UV absorbers were employed as the matrix to analyze polystyrene (PS) using MALDI-MS. The UV absorbers absorb UV radiation well, are not expensive, and are easily available materials. The analytical results using the UV absorbers were compared with that using anthracene-1,8,9-triol (DIT). DIT is the most common matrix for MALDI-MS analysis of PS. 1,18,19Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 329, Tinuvin 360, and Tinuvin P are UV absorbers of o-hydroxyphenyl benzotriazole derivatives. Tinuvin 1577 is a UV absorber of a hydroxyphenyl triazine derivative. Figure 1 shows the MALDI-MS spectra of PS obtained from the samples prepared using DIT and Tinuvin 234 as the matrix. Abundances of the [PS + Ag] + ions of the MALDI mass spectrum obtained using Tinuvin 234 were larger than those obtained using DIT by about twice. It is a very interesting result because DIT is known to be a proper matrix for MALDI-MS analysis of PS. The average molecular weights were about 4,000-4,200 as listed in Table 1. The average molecular weights for the Tinuvin 234 case were slightly larger than those for the DIT one by about 4%. The other UV absorbers of Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 329, Tinuvin 360, Tinuvin P, and Tinuvin 1577 were also employed as the matrix, and the analysis results are

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Mass Spectrometry

Cited by 185 publications

References 597 publications

Average and maximum charge states of arginine-containing dendrimer-like peptide ions formed by electrospray ionization

Average and maximum charge states of arginine-containing dendrimer-like peptide ions formed by electrospray ionization

Evaluation of Dissolved Species of Lanthanum in the Solutions Containing Different Amino Acids by Cation-Exchange Chromatography Coupled with Electrospray Ionization Mass Spectrometry

Role of a UV Absorber as a Matrix for Analysis of Polystyrene Using Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry

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