Chromatography FAQs | GC and HPLC *.PDF |
Restek ? |
- What Sets Restek Columns Apart from the Competition  |
NEW from Walt Jennings | |
GC and Capillary GC
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Koni's Korner * | |
Copyright 1992-1999 - Articles by Dr Konrad Grob and Prof Walt Jennings- All rights reserved repectively |
HPLC Faqs | NEW Silica materials ADVANTAGES- Use High Purity Silica - low metallic contect; improved analysis of "difficult" polar samples
- Highly uniform particle size - better column efficiency
- A trend to smaller ID and smaller particles size; reduced length / presure drop and solvent consumption
- Use of micropolished tubing and / or glass-lined
What's Wrong with C18 phases ?- Whilst being the standard HPLC phase :
- Results tend to be of poor reproducibiliy particularly using highly aqueous solvents and analysis of of polar samples
- Explanation - due to what has been reported as "chain fold-back/collapse" but also the phenomena is due to a phase transition for C18-Si-OH between 15-30degC
Answers use . . .
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C18 using an "embedded polar phase" silica linkage - Restek, GROM Analytik
- C16+C2 - a branched C18 ChromAB Corp Phase transition reduced to 0-10 degC
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