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VertiSep™ pHendure HPLC Columns
Practical Extreme pH in RP-HPLC
Using Hybrid Particle Based Packings
 
     Introduction
     Spherical hybrid organic-inorganic particles combine the high efficiency and excellent mechanical strength of silica with the wide pH stability range and reduced silanol effects of polymers. Reversed-phase HPLC packing based on hybrid particles exhibits excellent efficiency, selectivity and long lifetimes at alevated temperatures.


    The problem of extreme pH in silica column
    Silica-based materials are the most widely used packing for RP-HPLC due to the high efficiency and excellent mechanical strength. However, there are some limitations on these conventional silica-base materials.

     Short lifetimes below pH 2 (hydrolysis of bonded phase)
     Short lifetimes below pH 8 (dissolution of silica)
     Broad, tailing peaks for basic compounds
     Short life time at high temperatures

     Why operate outside pH2-8
    The mobile phase pH is an important factor in retention, selectivity andeffciency for polar compounds. pH also influences analyte ionisation, which is necessary for LC-MS. Finally, the stability of the analyte may be improved at high or low pH. A good column for low and high pH should offers acceptable lifetime, no bleed, stable retention and effciency.

     What is Hybrid particle based packings ?
    The Hybrid particle contains both silica and organosiloxane and shares the advantages of both. The Hybrid particle is prepared by solgel synthesis using organoslanes. This particle is as hard assilica and does not well or shrink in the presence of organic solvents. The pH stability of bonded phases based on this Hybrid particle exceeds that of silica-based bonded phases.   
 
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   .What is VertiSep™ pHendure
     The new VertiSep™ pHendure from Vertical Chromatography is a Hybrid organic-inorganic particle based packings providing extended pH Stability from 1-12, a novel solution to the problems exhibited by conventional solica-based and polymer-based packing material.

     What are the features ?

     Long lifetimes below pH 2 (Low pH stability)
     Long lifetimes above pH 8 (high pH stability)
     Long life time at high temperatures(stability of hybrid particle)
     Low bleed, ideal for both LC-MS and routine HPLC method development (stability of hybrid particle)

     VertiSep™ pHendure HPLC columns are packed with hybrid silica organosilane particle based packings providing pH stability pH 1-12 and high resolution, a novel solution to the problems on acidic or basic conditions exhibited by conventional silica-based columns.
     Hydrolysis of bonded phase will occur and causes loss of efficiency under acidic conditons with conventional silica-based column. VertiSep™ pHendure with the hybrid particle based packings solves this problem and provides excellent stability under acidic conditions offerring long lifetime.

     Dissolution of silica will occurs and causes tailing peaks under basic conditions with conventional silica-based column. VertiSep pHendure with the hybrid particle based packings solves this problem and provides excellent stability under basic conditions offering symmetrical peaks.

     VertiSep™ pHendure is low bleed, ideal for both LC-MS and routine HPLC method development.

     VertiSep™ pHendure C18 is 14% carbon loading offering higher capacity and greater resolution for all HPLC applications including USP L1.

     VertiSep™ pHendure Phenyl-Hexyl is 12% carbon loading offering an alternative selectivity to C18 for analytes containing aromatic rings or USP L11..

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Stability under acidic and high temperature conditions

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VertiSep™ pHendure C18

     Hybrid Particle columns were exposed to 1.5% Trifl uoroacetic acid in ACN/Water at pH 1.0 at 60 ℃ for 100 hours at a fl ow rate of 1mL/min, then tested the columns with a standardized test condition and Napthalene as test probe. VertiSep™ pHendure hybrid particle exhibits excellent stability under acidic conditions better than conventional silica-based packings
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Stability under basic conditions

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VertiSep™ pHendure C18

     Hybrid Particle columns were exposed to 0.2% Triethylamine in ACN/Water at pH 11.5 at 30 ℃ for 100 hours at a fl ow rate of 1mL/min, then tested the columns with a standardized test condition and amitriptyline as test probe. VertiSep™ pHendure hybrid particle exhibits excellent stability and provides symmetrical peak for basic compounds under basic conditions better than conventional silica-based packings.

 

 
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