Analytical laboratories routinely use chromatography in many applications, and it is commonly paired with mass spectrometry to detect, identify,and monitor compounds, proteins, or peptides in pharmaceutical, biological, chemical, and environmental samples.

THE PROBLEM is evidenced by what the column editor of LCGC North America wrote in the June 2011 edition, "Nowadays everybody is interested in increasing productivity, and for good reason.  Many analytical laboratories are experiencing increases in the number of samples with fewer personnel and the same number of instruments."  The editorial then notes that loading samples into an autosampler carousel and running overnight has limitations because "...many times those requesting the analytical data want (and perhaps need) the information more quickly than overnight."

Regarding the separation of large molecules (proteins), an article in the August 2012 edition of American Laboratory indicated that "both polyacrylamide gel electrophoresis (PAGE) and agarose slab-gel electrophoresis methods are time-consuming and labor-intensive and therefore need to be improved in terms of resolving power, throughput, and cost per analysis."

THE TECHNOLOGY of Pressurized Planar ElectroChromatography (PPEC) was collaboratively developed by scientists at Indiana University - Purdue University  Indianapolis and Purdue University (West Lafayette, IN) and is covered by patents issued to InChromatics by the Indiana University Research and Technology Corporation.  PPEC is a chromatographic technique in which rapid separation occurs under high pressure when a glass-backed sorbent layer (the media plate) is subjected to a large electrical potential that causes electroosmotic flow of a mobile phase.  The separation depends on several easily controlled variables including the electric field strength and the mobile phase composition.

PPEC allows high quality separations to be performed simultaneously on a large number of samples applied to the sorbent layer as spots either along a line (One-Dimensional, 1-D) or as a Two-Dimensional (2-D) array.  PPEC can require only seconds per sample, making the technique ideally suited for high-throughput separations.  Most separations to-date have been of small molecules, but separations of larger molecules, such as oligopeptides, have also been reported.

PPEC, as performed by the INCHROMATICS INSTRUMENT, offers the combination of several attractive features that are not shared by other techniques:

  • Rapid separation of small molecules in a multi-channel planar format:  up to 20 times faster than the traditional thin layer chromatography (TLC) technique that is utilized in the discovery organic/medicinal chemistry,
  • True two-dimensional (2-D) separations of proteins and peptides will be possible:  initial experiments show marked improvements in both separation time and resolution of peptide fragments in the 1-D mode,
  • Detection technique flexibility: compounds can be detected via Desorption Electrospray Ionization Mass Spectrometry (DESI-MS), fluorescence, ultraviolet/visible spectroscopy (UV-Vis), staining and many other techniques because after separation, compounds are accessible on the surface of the media and thus are amenable to treatment with various reagents.  This accessibility allows biological assays to be performed without removing analytes from media, 
  • Green chemistry:  PPEC may play a notable role here given the low volume of solvent used, the ability to separate multiple samples simultaneously (low solvent volume per sample), the fact that analytes do not need to be transported to a detector, as such transport is likely to use a relatively large volume of solvent, and
  • Trace components:  the high efficiency of PPEC results in the separated spots being small, or, stated differently, in very sharp peaks, which facilitates detection and quantitation.

The Problem ... and the Technology to Address It

Separation of a 5-component mixture on a LiChrospher plate at 2.5 kV.

InChromatics LLC