Description
GP-C18 uses full coverage bonded silica packing, which provides exceptionally high stability.
The unique mono-functional bonding chemistry of GP-C18 avoids the formation of multiple C18 layers. Such uniform stationary phase
allows the separation
to achieve high selectivity and high efficiency.
Packing

Silica:
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Spherical, high purity (<10 ppm metals)
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Pore size:
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120Å
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Particle size:
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1.8, 2.2, 3, 4, 5, 7, and 10 µm
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Pore volume:
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1.0 ml/g
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Surface area:
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300 m²/g
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Phase structure:
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Monomeric and fully endcapped
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% Carbon:
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17%
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Characteristic
· Highly controlled chemistry of monolayer formation and end-capping
· Extremely high column-to-column reproducibility
· High selectivity and efficiency for separations
· Suitable for separations of acidic, neutral and basic organic compounds,
as well as pharmaceuticals, peptides, and others
· Recommended for separations in organic or mixed organic/aqueous mobile phases.
Stability
SepaxGP-C18 uses full coverage bonded silica packing, which provides exceptionally
high stability. Figure below
shows the highly reproducible retention time for three standard compounds: aniline,
anisole and toluene
after 13,000 column volume runs in a mobile phase of 85% methanol and 15% water.
Such high stability allows SepaxGP-C18 extremely suitable for validation of various analytes.

Selectivity for GP-C18 and the Competitors' C18 Phases
Selectivity is very important for detection of the components of low abundance and
impurities from
the analysis of pharmaceuticals in the real applications. The comparative tests shown
below from the method development of
a drug molecule clearly demonstrated that GP-C18 is among the best products for high selectivity and sensitivity in detecting low
abundant components and the impurities.

(Courtesy of Dr. Fang Liu, Novartis)
Conditions
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Column:
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Inertsil ODS-3, 3 µm (Varian)
Xterra RP18, 3.5 µm (Waters)
Suplex PKB-100, 5 µm (Supelco)
Sepax GP-C18, 3 µm
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Mobile phase:
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A: 99% Boric buffer (5.0 mM, pH 7.0)/1% Acetonitrile
B: 40% Boric buffer (5.0 mM, pH 7.0)/60% Acetonitrile
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Gradient:
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0-3 min (100% A); 3-38min (0-100%B); 38-43 min (100% B)
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Column Temperature:
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50 °C
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Flow rate:
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1.0 mL/min
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Detection wavelength:
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210 nm
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Sample:
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A real pharmaceutical sample (undisclosed)
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