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Technical Support

 
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Column Recommendation Service

Whether it’s a new method, published application or upgrade of an existing method, we have the experience to be able to recommend the very best column for your individual requirement. We know columns and we know chromatography. Crawford are not tied to any one manufacturer and will recommend the most appropriate column for what you need to do. Whether it’s pharmaceutical, forensic, petrochemical, healthcare, food and drink, environmental or less common fields, you can be sure we’ve worked with these areas.

Part of the skill in recommending the optimal column is ensuring that it’s used in a method with conditions that allow the column to work at its best. Our technical team are experienced method developers with a backgrounds in high throughput commercial labs who really understand how to develop and optimise a robust, reliable method for most applications. We know how to get the best from the best products.

HPLC – we use a range of techniques to select the optimal HPLC column. Our experience, applications or our in-house written tool which compares data for nearly all common columns obtained via the independent USP database. We use this not only to find column with similar characteristics, but also ones with diverse characteristics if you need a variety of phases for development.

GC – we use a combination of application data, retention indexes and method development experience to choose the correct column for what you’re doing. Whether you’re using capillary, capillary PLOT or packed columns we’ll recommend you the correct column for what you’re analysing.

SPE – our technical team have extensive method development in SPE and use this to recommend the optimal solution for your molecules and matrices. We will supply you with free sample cartridges AND starting conditions to allow you to get started quickly.

C18 spider diagram
 
  Column 1 Column 2 Column 3 Column 4
Manufacturer YMC Zorbax Thermo Zorbax / Varian
Brand Triart Eclipse Plus Hypersil Gold Pursuit
Style C18 C18 C18 C18
H 0.929 1.03 0.881 1.001
H/10 0.0929 0.103 0.0881 0.1001
S -0.02 0.007 0.002 0.004
A -0.19 -0.072 -0.017 -0.166
B -0.033 -0.02 0.036 0.012
C(2.8) -0.023 -0.004 0.162 0.245
C(7.0)/10 -0.0139 0.002 0.0479 0.0226
C(7.0) -0.139 0.02 0.479 0.226
  Difference 0.203 0.5156 0.4047
 
H   Hydrophobicity.
S   Steric (shape).
A   Un-ionised silanols.  Can produce hydrogen bonds with bases.
B   Ability of phase to behave as base. Better retention of acids and possible replusion of bases.
C(2.8)   Active silanols causing tailing of bases. Caused by metal ions etc. Reduced by encapping.
C(7.0)   Total ion exchange capacity. Reduced by endcapping. Effects acids and bases but not neutrals.
 

 

For any information or advice on any of the above



or phone 01357 522 961
  Repeat analysis infographic
 
 
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