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Molecular Weight Determination by Counting Molecules

Tian, Yuxi LU ; Kuzimenkova, Marina LU ; Halle, Johannes; Wojdyr, Michal; Mendaza, Amaia Diaz de Zerio; Larsson, Per-Olof LU ; Muller, Christian and Scheblykin, Ivan LU (2015) In The Journal of Physical Chemistry Letters 6(6). p.923-927
Abstract
Molecular weight (MW) is one of the most important characteristics of macromolecules. Sometimes, MW cannot be measured correctly by conventional methods like gel permeation chromatography (GPC) due to, for example, aggregation. We propose using single-molecule spectroscopy to measure the average MW simply by counting individual fluorescent molecules embedded in a thin matrix film at known mass concentration. We tested the method on dye molecules, a labeled protein, and the conjugated polymer MEH-PPV. We showed that GPC with polystyrene calibration overestimates the MW of large MEH-PPV molecules by 40 times due to chain aggregation and stiffness. This is a crucial observation for understanding correlations between the conjugated polymer... (More)
Molecular weight (MW) is one of the most important characteristics of macromolecules. Sometimes, MW cannot be measured correctly by conventional methods like gel permeation chromatography (GPC) due to, for example, aggregation. We propose using single-molecule spectroscopy to measure the average MW simply by counting individual fluorescent molecules embedded in a thin matrix film at known mass concentration. We tested the method on dye molecules, a labeled protein, and the conjugated polymer MEH-PPV. We showed that GPC with polystyrene calibration overestimates the MW of large MEH-PPV molecules by 40 times due to chain aggregation and stiffness. This is a crucial observation for understanding correlations between the conjugated polymer length, photophysics and performances of devices. The method can measure the MW of fluorescent molecules, biological objects, and nanoparticles at ultimately low concentrations and does not need any reference; it is conformation-independent and has no limitations regarding the detected MW range. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Letters
volume
6
issue
6
pages
923 - 927
publisher
The American Chemical Society
external identifiers
  • wos:000351563100002
  • scopus:84925234768
ISSN
1948-7185
DOI
10.1021/acs.jpclett.5b00296
language
English
LU publication?
yes
id
dc0f5f25-b7cd-4209-b4ba-23f9f593bf1c (old id 5282031)
date added to LUP
2015-04-24 13:10:56
date last changed
2017-10-22 04:26:08
@article{dc0f5f25-b7cd-4209-b4ba-23f9f593bf1c,
  abstract     = {Molecular weight (MW) is one of the most important characteristics of macromolecules. Sometimes, MW cannot be measured correctly by conventional methods like gel permeation chromatography (GPC) due to, for example, aggregation. We propose using single-molecule spectroscopy to measure the average MW simply by counting individual fluorescent molecules embedded in a thin matrix film at known mass concentration. We tested the method on dye molecules, a labeled protein, and the conjugated polymer MEH-PPV. We showed that GPC with polystyrene calibration overestimates the MW of large MEH-PPV molecules by 40 times due to chain aggregation and stiffness. This is a crucial observation for understanding correlations between the conjugated polymer length, photophysics and performances of devices. The method can measure the MW of fluorescent molecules, biological objects, and nanoparticles at ultimately low concentrations and does not need any reference; it is conformation-independent and has no limitations regarding the detected MW range.},
  author       = {Tian, Yuxi and Kuzimenkova, Marina and Halle, Johannes and Wojdyr, Michal and Mendaza, Amaia Diaz de Zerio and Larsson, Per-Olof and Muller, Christian and Scheblykin, Ivan},
  issn         = {1948-7185},
  language     = {eng},
  number       = {6},
  pages        = {923--927},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Letters},
  title        = {Molecular Weight Determination by Counting Molecules},
  url          = {http://dx.doi.org/10.1021/acs.jpclett.5b00296},
  volume       = {6},
  year         = {2015},
}