ZORBAX ECLIPSE XDB FOR USP SEPARATIONS
Not All L1 Columns are Alike!
That's why the ZORBAX Eclipse XDB-C18 (eXtra
Densely Bonded) belongs in your laboratory. The USP
definition of an L1 column
is "a chromatographic reagent packing. Octadecyl silane
chemically bonded to porous silica or ceramic microparticles 3 to
10 mm in diameter." (1995 USP 23, General Chapter 621.)
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Conditions
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LC:
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HP 1090 Series II
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Column:
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ZORBAX Eclipse XDB-C18,
Part No. 999367-902
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Mobile Phase:
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55% ACN; 45% 50-mM K2HPO4 (pH 7.5)
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UV:
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224 nm; 23°C
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The Eclipse XDB-C18 is a state-of-the-art alternative
to the original L1-type columns used for pH 3.0-8.0
analyses. The Eclipse XDB-C18 offers:
- Improved peak shapes
- Longer column life
- Higher efficiency
- Faster analysis time
For low-pH (1-3) separations, ZORBAX StableBond columns
are recommended. For pharmaceutical assays, however,
intermediate pH (6-8) is often specified, because compounds
may be unstable,
aggregate, or not sufficiently
retained for separation.
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USP Method for Buspirone HCI
Buspirone is an Anxiolytic.
USP Requirements: Rs >4; Peak Response %RSD
of 5 Replicate Injections <2.0
Improved peak shape and higher efficiency
using ZORBAX Eclipse XDB-C18
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Conditions
|
|
LC:
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HP 1090 Series II
|
|
Column:
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ZORBAX Eclipse XDB-C18,
Part No. 999367-902
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Mobile Phase:
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40% ACN; 60% 10-mM KH2PO4 (pH 7.5)
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UV:
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254 nm; 23°C
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Bonded-Phase Chemistry
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Intermediate and higher pH values may also provide unique selectivity
by increasing the retention of basic compounds with higher
pKa's. ZORBAX Eclipse XDB columns are specially designed for
optimum stability at intermediate pH.
At mid-range and high pH, silica-based columns undergo slow
dissolution that negatively impacts the peak shapes of basic
compounds. Eclipse XDB columns are manufactured with unique
double endcapping on ultrapure porous silica microspheres to
prevent this slow dissolution and extend column life. This
chemistry minimizes electrostatic interactions
of the analyte with underlying silanols and reduces dissolution
to maintain good peak shape at intermediate pH.
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USP Method for Methotrexate
Methotrexate is Used as an Antineoplastic and Antirheumatic
USP Requirements: RS > 8; Peak Response %RSD of 5 Replicate Injections
<2.5
Improved peak shape and higher efficiency
using ZORBAX Eclipse XDB-C18
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Conditions
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LC:
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HP 1090 Series II
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Column:
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ZORBAX Eclipse DXB-C18,
Part No. 999367-902
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Mobile Phase:
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10% ACN; 90% phosphate/citrate buffer (pH 6.0)
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Buffer:
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0.2 M K2HPO4; 0.1 M citric acid (63:37)
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UV:
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302 nm; 23°C
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