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msRepeatFinder Polymer Analysis Software

Definitive Polymer Analysis Software!!

Visualizes complicated mass spectral data and accelerates information sharing!

Compositional distribution of polymers

msRepeatFinder combines Kendrick Mass Defect (KMD) and Kendrick Mass Remainder (KMR) plots to visualize compositional distributions of homopolymers with different end groups. The program also calculates parameters related to molecular weight distributions by grouping and color coding each polymer series.

Mass spectrum of a polyethylene oxide mixture with different end groups
Mass spectrum of a polyethylene oxide mixture with diffeent end groups
Total ion intensity Center of KMD value Center of NKM value Number average molecular weight(Mn) Weight average molecular weight(Mw) Polydispersity
826378 0.0245 1092.1 1092.8 1109.3 1.015
239802 -0.0635 1433.7 1434.5 1453.0 1.013
175311 -0.0920 1347.5 1348.3 1366.1 1.013
90119 -0.1060 1371.1 1371.9 1387.5 1.011
17689 0.0912 1279.8 1280.5 1291.2 1.008

Elemental composition estimation of polymer components

By specifying two peaks that represent two molecular species that differ 1 in the degree of polymerization, the elemental composition of the monomer and the terminal group can be estimated.

Differential analysis between 2 samples

In polymer analysis, there are many situations where you want to compare two samples, such as deterioration analysis and lot-to-lot comparison. However, it was difficult to intuitively discriminate the difference by simply superimposing the KMD plots (right in the figure below).

Using the differential analysis function newly implemented in the msRepeatFinder, we analyzed from the mass spectra of 3 each of 2 samples. The total ion intensity was normalized and the difference was displayed (left in the figure below). The predominant ions before deterioration are displayed in red, and the predominant ions after deterioration are displayed in green. It is also possible to create a Volcano Plot (right in the figure below) and select only the ions that have a statistically significant difference on the Volcano plot, and display them on the KMD plot.
The differential analysis function makes it possible to selectively visualize polymer series that have a significant difference before and after deterioration.

Gel permeation chromatography (GPC) combined with high mass-accuracy MALDI-TOFMS

To analyze highly polydisperse polymers, it is effective to combine GPC with high mass-accuracy MALDI-TOFMS. This process displays mass spectra of multiple fractions on Remainder of Kendrick Mass (RKM) plots for visual presentation of compositional distributions.

Mass spectral data of highly polydisperse polycaprolactone after being fractionated by GPC
Overlaid RKM plots of mass spectra of all fractions

* The data was acquired in collaboration with the National Institute of Advanced Industrial Science and Technology

MS/MS structural analysis of polymers with different end groups

High energy collision-induced dissociation, which is a fragmentation method specific to MALDI-TOF-TOF, is effective in acquiring various structural information. RKM plots can visualize the difference of end groups.

Product ion spectra polyethylene oxide with different end groups
Overlaid RKM plots of 3 product ion spectra
Overlaid RKM plots of 3 product ion spectra

Analysis of copolymers

In mass spectral data of copolymers, numerous peaks with small mass differences are typically observed.
Fraction Base KMD plots can clearly visualize such peaks compared to conventional KMD plots.

Mass spectrum of EO-PO block copolymer
Mass spectrum of EO-PO block coplolymer EO-POブロック共重合体のマススペクトル
KMD plot(Left) / Fraction base KMD plot(Right)

Polymer analysis using field desorption (FD)

In FD, types of polymers to be desorbed and ionized change over time as the current to the emitter is increased.
In KMD plotting, polymers separated over time can be overlaid for visualization.

Analysis of a polypropylene oxide and polystyrene mixture
Analysis of a polypropylene oxide and polystyrene mixture


  • Peak lists (up to 10 lists can be overlaid)
  • KMD/KMR plots
  • Fraction base KMD plots
  • Remainder of KM (RKM) plots
  • Estimated circles of homopolymer end groups (on KMR plots)
  • Grouping
    • Color coded groups
    • Enable/disable display of polymer series groups
    • Calculating average molecular weight/polydispersity of groups
    • Export polymer series groups


  • Peak list input format: m/z and ion intensity
  • The effectiveness of processed results is determined by the mass accuracy of peak lists provided.

Microsoft® Windows® 7 Service Pack 1 (64 bit) or Microsoft® Windows® 10 (64 bit).
For the PC, MS-57043PCJ or equal is recommended. Microsoft, Windows, PowerPoint and Microsoft Office e registered trademarks or trademarks of Microsoft Corporation in the US and other countries.
Microsoft Word is the product name of Microsoft Corporation.

*Specifications and appearance are subject to change without notice due to modification




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