MS Wil GmbH

P.O. Box 1426  - CH 8048 Zurich
Phone +41 71 912 12 77
Fax +41 71 912 12 79
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pI-Trap™ represents a revolutionary new instrument for gel-free pI-fractionation of peptide and protein mixtures.


Biomotif PI Trap instrument


  • Fast (<1 h) separation in ESI-friendly solution
  • Easy fraction collection, up to 30 fractions
  • On-line clean-up of sample
  • Fractionation of raw samples, e.g., intact blood plasma or serum
  • Couple on-line to any API-Mass Spectrometer 
  • Orthogonal dimension to RP-LC-MS in Deep-Proteomics
  • Large capacity (up to 100 μg) for enrichment of low abundance molecules
  • Minimal sample losses
  • Rapid isolation of a defined pI region
  • Accurate pI determination of your molecule
  • A push-button operation

Below graphics illustrates the function of the fractionation device:

The pI-trap utilizes a series of vessels with a capillary passing through each vessel. Part of the capillary in each vessel is replaced by a semipermeable membrane. The vessels contain buffer solutions with different pH values, so that a pH gradient is effectively established inside the capillary. The buffer solution in each vessel has an electrical contact with a voltage divider connected to a high-voltage power supply, which established electrical field along the capillary. When a sample (a mixture of peptides or proteins) is injected in the capillary, the presence of the electrical field and the pH gradient separates these molecules according to their isoelectric points (pI).

click for details about the pI-trap


Biomotif Trap

Heart of the device is the pI-Cell™, based on proprietary microfluidic technology. Take it as an “electrical column”, capturing charged molecules according to their isoelectric point.

Interested in signing in for a demo or an instrument evaluation ? 

Please contact This email address is being protected from spambots. You need JavaScript enabled to view it. for details.


1. Chingin, K.; Astorga-Wells, J.; Pirmoradian Najafabadi, M.; Lavold, T.; Zubarev, R. A.

Separation of polypeptides by isoelectric point focusing in electrospray-friendly solution using multiple-junction capillary fractionator, Anal. Chem. 2012, 84, 6856-6862.


2. Pirmoradian, M.; Zhang, B.; Chingin, K.; Astorga-Wells, J.; Zubarev, R. A.

Membrane-assisted isoelectric focusing device as a micro-preparative fractionator for two dimensional shotgun proteomics, Anal. Chem, 2014, 86, 5728-5732.


3. Pirmoradian, M.; Astorga-Wells, J.; Zubarev, R. A.

Multijunction Capillary Isoelectric Focusing Device Combined with Online Membrane-Assisted Buffer Exchanger Enables Isoelectric Point Fractionation of Intact Human Plasma Proteins for Biomarker Discovery. Anal Chem 2015, 87, DOI: 10.1021/acs.analchem.5b03344.


Further publications:

Biomotif PITrap brochurePI trap and 2D proteomics

iP trap ElectrosprayiP trap and biomarker discovery