Trapping of wide range mass-to-charge ions and dependence on matrix amount in internal source MALDI-FTMS

It is well known that the mixing ratio affects the molar mass distribution of synthetic polymers determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Surely, the molar mixing ratio determines whether a mass spectrum will be obtained or not. However, depending on the mass range, several effects such as multimer formation occur, which might be a source of errors in molar mass distribution calculations. In this study, the effect of mixing ratio was investigated for several synthetic polymers, including polystyrene (PS), poly(dimethylsiloxane) (PDMS), poly(ethylene glycol) (PEG), and poly (methyl methacrylate) (PMMA) using statistical designs of experiments. The 2 3 full factorial design was found to be suitable in the study of more than 1000 samples. The obtained MALDI mass spectra as well as the ANOVA statistics show that the mixing ratio affects the molar mass distribution. The optimal mixing ratio for a defined synthetic polymer depends on the studied combination (matrix, cationization reagent, solvent). (J Am Soc Mass Spectrom 2010, 21, 1870 -1875

mentioning

confidence: 99%

Investigating the effect of mixing ratio on molar mass distributions of synthetic polymers determined by MALDI-TOF mass spectrometry using design of experiments

Brandt¹,

Ehmann²,

Otto

2010

“…In the past few years, a number of researchers attempted to develop suitable matrices and sample preparation methods for the analysis of wide ranges of PEGs and found difficulty in the analysis of high molecular mass PEGs (up to 40 kDa). PEGs are analyzed by conventional matrices such as 2,5-dihydroxybenzoic acid (DHB), dithranol (DT), 2-(4-hydroxyphenylazo)benzoic acid (HABA), etc. ,,− Brandt et al reported the effect of different solvents on the analysis PEG4820 and concluded that PEG4820 showed better S/N ratios using solvents such as methyl ethyl ketone and ethyl acetate among others . Meier et al described the advantage of multiple-layer sample spotting of matrix, doping agent, and analyte on top of one another over conventional dried-droplet sample spotting method to improve the analysis of PEGs up to 40 kDa. , In another study, Malvagna et al carried out analysis of poly(ethylene oxide) ( M w ∼ 100 kDa) using DHB as matrix and observed broad range molar mass distribution .…”

Section: Introductionmentioning

confidence: 99%

2-Cyano-3-(2-thienyl)acrylic Acid as a New MALDI Matrix for the Analysis of a Broad Spectrum of Analytes

Yerra

Bharath

Dadinaboyina

et al. 2020

A low-cost synthetic 2-cyano-3-(2-thienyl)acrylic acid (CTA) is developed as a new MALDI matrix for the analysis of various classes of compounds such as lipids (e.g., fatty acids), peptides, proteins, saccharides, natural products (i.e., iridoids), PEGs, and organometallics in the positive-ion mode. The difficulty in the analysis of high molecular mass PEGs was overcome by using CTA as matrix even at low concentrations. Both high molecular mass proteins and peptides were successfully analyzed using CTA. The mass spectra of all of the studied analytes with CTA showed high signal-to-noise (S/N) ratios and spectral resolutions when compared to other conventional matrices such as SA, DHB, DT, and HCCA. However, in the case of peptide analysis with CTA, the resulting mass spectra are found to be similar to that of the well-established HCCA matrix. On the basis of the physicochemical properties of the analytes, the CTA works as a proton/ cation or electron-transfer matrix. It proves that the CTA can be used as a common matrix for the analysis of majority classes of analytes instead of using a specific matrix for the particular class of analytes. Further, the CTA provides an advantage in the analysis of unknown samples as it rules out ambiguity in the selection of particular matrix and it may also offer a complete profile of the tissue surface in the MALDI-imaging experiments.

“…FTICR-MS can separate isobaric peaks at a resolution over 100 k. However, the observation of molecular weight distribution of polymers using a combination of MALDI and FTICR-MS encounters problems, mainly caused by mass discrimination when ions are trapped and stored in the ICR cell [16–19]. Although the superb resolving power and mass accuracy of FTICR-MS make it an eminently useful technique, MALDI-FTICR-MS is not ideal for polymer analysis at this stage.…”

Section: Introductionmentioning

confidence: 99%

Structural Characterization of Polymers by MALDI Spiral-TOF Mass Spectrometry Combined with Kendrick Mass Defect Analysis

Sato

Nakamura

Teramoto

et al. 2014

127

High-resolution mass spectrometry (HRMS) continues to play an important role in the compositional characterization of larger organic molecules. In the field of polymer characterization, however, the application of HRMS has made only slow progress because of lower compatibility between matrix-assisted laser desorption/ionization (MALDI) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS). In this study, a newly developed type of MALDI high-resolution time-of-flight mass spectrometry (TOFMS) with a spiral ion trajectory (MALDI spiral-TOFMS) was applied to the structural and compositional characterization of polymers. To create a graphical distribution of polymer components on a two-dimensional plot converted from complex mass spectra, we adopted a slightly modified Kendrick mass defect (KMD) analysis based on accurate masses determined using spiral-TOFMS. By setting the Kendrick mass scale based on the mass of the repeating units of a given polymer, components with common repeat units lined up in the horizontal direction on the KMD plot, whereas those components with different structures were shifted vertically. This combination of MALDI spiral-TOFMS measurement and KMD analysis enabled the successful discrimination of the polymer components in a blend of poly(alkylene oxide)s, the compositional analysis of poly(ethylene oxide)/poly(propylene oxide) block copolymers, and profiling of the end-group distribution of poly(ε-caprolactone)s synthesized under different conditions.ᅟ