- Ordering Information
- Features
Stable vinyl copolymer base
Stable pH range 2-12
300 Å pore size
Sharp resolution, high NTP
Stable in all organic solvents
Expanded applications: peptides, proteins
Efficient separation of any basic substance
Amenability to washing with alkaline solutions
Available as C4, C8 and C18
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In
recent years reversed phase chromatography has become predominant
throughout high performance liquid chromatography applications.
Column packings have generally been alkyl-bonded silica gels such
as ODS, and, to a lesser extent, polystyrene-based porous gels.
Silica based phases are mechanically stable and generally high in
NTP. However, they cannot be used under alkaline conditions and
their residual silanol groups tend to adsorb organic bases.
Conventional
polystyrene gels are free from residual silanol groups and can be
used under alkaline conditions but they are also low in NTP and
undergo excessive shrinkage and swelling with various solvents,
thus limiting the range of eluents that can be used. Polymer based
reversed phase columns have, therefore, generally been viewed as
inferior in strength and separation efficiency.
apHera™
reversed phase columns were developed specifically to provide the
superior advantages of both silica and polystyrene columns, without
the disadvantages of either. This was accomplished using a vinyl
alcohol copolymer base that keeps the surface wetted even with high
carbon loads. The columns are packed with butyl (C4), octyl (C8)
or octadecyl (C18) packings obtained by the introduction of the
alkyl function on the hydroxyl groups of vinyl alcohol copolymers.
The porous structure has an average pore diameter large enough to
produce ideal results for small analytes, peptides and small proteins.
These columns equal silica based columns in separation efficiency
with organic solvents but provide efficiency with buffered and alkaline
solutions not possible on silica. Shrinkage and swelling are minimal
in a broad range of solvents, and the high NTP values of these columns
are practically unaffected by differing solvent polarities, unlike
polystyrene based polymer columns. One of the most significant features
is the logical elution order of alkylated bases where retention
increases proportionately with increasing chain length.
The
apHera™ columns represent a fundamental advance in liquid chromatography
with a greatly expanded field of reversed phase applications.
We also offer apHera NH2 Amino
columns for carbohydrate analysis.
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