Agilent Technologies ZORBAX Guide D'utilisation page 7

recommended starting Gradients
stationary phase
Most reversed-phase
columns
ZORBAX Eclipse PAH*
ZORBAX Bonus-RP
Large molecule columns
(e.g., Poroshell 300,
ZORBAX 300SB columns)
*Best column lifetime is achieved at < 40 °C.
usage notes
5% methanol or acetonitrile initially and 100%
methanol or acetonitrile as the final solvent.
30 or 40% acetonitrile initially, to 100%
acetonitrile as final solvent. It may be necessary
to cool column to 15 to 20 °C for improved
resolution.
Lower concentration of organic mobile phase
modifier is required for compound elution,
compared to traditional long-chain alkyl
stationary phases.
Separations of polypeptides, proteins, DNA
fragments, etc. often use trifluoroacetic or
formic acid modifier for pH control and/or as
an ion-pairing additive for desired retention
and selectivity. Organic buffers such as TRIS
are especially useful for intermediate pH
applications.
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