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Celixir pH, stable EOF at any pH

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Dynamic Coating for Capillary Electrophoresis

What Is CElixir-pH™ & how does it work?

Click here to view an animated graphical presentation of the Double Layer, Dynamic Coating for CZE.

CElixir™ is a patented1, double layer, dynamic coating system that will make your CZE more reproducible. CElixir™ makes CZE useful in the pH range of 1.0 to 9.2.0 in your lab with astonishing speed and precision. Unlike traditional CZE, the two ionic solutions of CElixir™ will produce very robust EOF allowing you to develop methods that are most optimal for your samples. You can now select the pH where your analytes are most ionized or at or below your samples pK. Selectivity, efficiency, speed and precision are now available to you with CZE.

The two polyionic solutions of CElixir™ are applied to a bare fused silica capillary producing a very stable polymeric coating on the wall. First the cationic, polymer of the Initiator Solution™(A) binds to the ionized silanol sites of the capillary wall. Then the anionic polymer of the Accelerator Solution™(B), with a vast excess of negative charge, is added. Thus, there is an increase in the negatively charged sites relative to the bare fused silica wall that is always fully charged. Most importantly, however, is that both the exposed polymer layer (negatively charged) and the base polymer layers are washed off between runs by a NaOH solution rinse. A virgin layer of both polymers is replaced before each analysis. This gives previously unheard of reproducibility independent of source or age of the bare fused silica.

Reproducible CZE methods from run to run, capillary-to-capillary or instrument-to-instrument are now possible with CElixir™.

How does it work?
Two solutions of CElixir™ are placed in three vials on your HPCE instrument and are automatically applied to the capillary before and between runs. The CE practitioner is no longer relying on the fused silica capillary as the main component of the separation mechanism and EOF. The ionic polymers in CElixir™ now provide this separation mechanism, making it “portable”, controllable and reproducible. The solutions are always the same on any capillary you use and on any HPCE instrument that you use and therefore the EOF and CZE conditions are always the same anywhere any time.

Low pH Yet High Flow Rate
Even at very low pH (as low as 1.7), CElixir™ has a very fast and reproducible EOF. If you change the pH from run to run, the resulting change in EOF speed will be negligible. This allows you to use pH as a solubility tool, a selectivity tool or as a sample matrix option to retain the biological activity of your samples. Since you are re-apply the coating before each run and the wall adsorption effects are minimized the inherent capillary inconsistencies experienced at low pH are eliminated. Precision, speed and reproducibility are increased over normal CZE.

Average Migration Time of Heroin Powder Using CElixir™
Cap No. Peak 1 Peak 2 Peak 3 Peak 4 Peak 5 Peak 6
1 2.910 2.954 3.029 4.072 4.217 4.705
2 2.916 2.961 3.304 4.083 4.231 4.721
3 2.908 2.954 3.029 4.072 4.222 4.718
4 2.858 2.903 2.979 3.972 4.112 4.576
5 2.894 2.942 3.017 4.074 4.223 4.691
6 2.894 2.942 3.018 4.057 4.202 4.686
7 2.881 2.928 3.003 4.029 4.175 4.659
%CV 0.638 0.0622 0.596 0.894 0.931 0.995

This chart shows the results using seven different Capillaries with CElixir™ at pH 6.6 and run six times each. This shows how stable the EOF and migration times are using CElixir™.

Features of CElixir:
  • Increases Precision of your EOF
  • Increases Reproducibility of your HPCE
  • Can be automated
  • pH Independent
  • Shifts Adsorption Equilibria
  • Increases EOF Speed
  • Lower Cost v. HPLC
  • No Buffer Preparation Needed
  • No Organics or Hazardous Material Used
Benefits of CElixir:
  • Makes Quantification of Peaks Easy and Reliable
  • Gives you the confidence needed
  • Easy to use, anyone in the lab can use it
  • Use pH to control ionization of your sample for selectivity or to maintain biological activity
  • Minimize Sample loss and increase reproducibility
  • Shorter Analysis time, Increase lab throughput
  • Save Money buying solvents and disposal costs
  • Save Time and Increase Repeatability of Method
  • Solutions are stable and safe and easily disposed of

1 Patent No. 5,611,903