A new procedure for quantitative correction of matrix-assisted laser desorption/ionization time-of-flight mass spectrometric response

Abstract

A simple procedure for the correction of the decreasing detection response in a Matrix-assisted laser desorption/Ionization time-of-flight (MALDI-TOF) mass spectrum with increasing ion mass is reported. On the basis of the experimental MALDI-TOF mass spectrum of a mixture of four polymethylmethacrylate (PMMA) standards (molecular masses in the range 4-100 kDa), present in equal molar abundance, an equation describing the MALDI-TOF response has been derived. This equation has been used to correct any subsequently recorded MALDI spectrum. As an example, the procedure has been applied here to normalize the MALDI-TOF mass spectrum of a 1,20-di(bisphenoxy-A)eicosane based copolyformal (I) containing porphyrin units in the main chain. #

Towards a Quantitative Interpretation of Polymer Distributions from MALDI‐TOF Spectra

“…A number of proteins and other substances [13,[17][18][19][20][21][22] exist, which can be regarded as valuable calibrants, although their usefulness must be tested beforehand. In reality, a combination of matrix material and solvent is used other than the one employed for the polymer analysis, [22] assuming that this has only a negligible influence on mass calibration.…”

“…Only a limited number of publications [11,21,30,[39][40][41] are dealing with the determination of mass discrimination. The existence of such an effect can be deduced from the observation of a decreasing signal intensity in conventional ionizing detector MALDI-TOF mass spectrometers [42,43] with increasing molar masses and from the necessity to increase the laser energy when polymers with higher molar masses are investigated.…”

Hydrolytic Degradation of Synthetic Polytrimethylene Terephthalate and Characterization by MALDI-TOF Mass Spectrometry

“…Although, to derive quantitative molar-mass distribution, the ionization yield of various oligomers must be independent of chain size and the detector should show a constant response to ions regardless of mass of the oligomers, the ion yield and the detector response usually decrease with chain length in many cases. 21 One solution for this problem is to produce samples with sufficiently low polydispersity close to 1 by a fractionation method such as size exclusion chromatography. 22 However, since the mass range of the cyclic oligomers is relatively limited, the mass discrimination can be regarded not to be very severe in our case.…”

Highly untangled multiwalled carbon nanotube@polyhedral oligomeric silsesquioxane ionic hybrids: Synthesis, characterization and nonlinear optical properties

“…The MALDI investigations were performed by loading on the plate a 0.1 mmol sample and 40 mmol matrix trans-2-[3-(4-tert-butylphenyl)-2-methyl-2propenylidene]-malonitrile (DCTB), with DMF as solvent. Mass spectrometer calibration was performed as reported in previous cases [31,32]. Gel Permeation Chromatography (GPC) analyses were performed on a PL-GPC 110 (Polymer Laboratories) thermostated system, equipped with three PL-gel 5 lm columns (two Mixed-D and one Mixed-E) attached in series.…”