- simple equipment tests and selection criteria for columns, buffers etc.
- specific problems and how to solve them
- options for optimizing separations.
SIMPLE TESTS AND DECISION CRITERIA
Tip 01: What is in a name of a column material?
Tip 02: Is this C18 column the right choice for my sample?
Tip 03: Why are polar solutes well separated with one C18 column and barely with another?
Tip 04: How can I clean the RP–phase fast?
Tip 05: How do I best degas my mobile phase?
Tip 06: Methanol or acetonitrile?
Tip 07: The pH–value of the mobile phase is too high/too low – what to do?
Tip 08: Which is the right ionic strength of the buffer?
Tip 09: How to make sense of the dead volume of an isocratic equipment?
Tip 10: Taking over a gradient method – the influence of the instrumentation
Tip 11: Does the pump work correctly, precisely or accurately?
Tip 12: How to test an HPLC equipment and its modules?
Tip 13: Injection of solutes out of aqueous solutions
Tip 14: Which is the largest tolerable injection volume?
Tip 15: How critical are temperature changes? PartTip I: General comments, Detector
Tip 16: How critical are temperature changes? Part TIP II: Column, Separation
Tip 17: How to choose an HPLC equipment and a supplier?
Tip 18: Is the current method a robust one?
PROBLEMS AND THEIR SOLUTIONS
Tip 19: Sample preparation – how critical are which mistakes?
Tip 20: Flushing of an HPLC equipment
Tip 21: Junk in the UV detection cell
Tip 22: The lamp is new – what happened to the peak?
Tip 23: What are the causes for pressure changes or deviations?
Tip 24: Is the right or the left pump head defect?
Tip 25: Baseline noise and damping
Tip 26: The retention times increase – is it the pump or the mobile phase?
Tip 27: Which buffer is right for which pH–value?
Tip 28: An interesting alternative for the separation of acids and bases with buffer
Tip 29: What can be the reasons for a change in retention times?
Tip 30: I use up a lot of RP–columns, what should I do?
Tip 31: Why does my normal phase system not work anymore?
Tip 32: Chemical tailing at the presence of metal ions
Tip 33: How to avoid memory effects?
Tip 34: How do the default values on my PC affect the resolution?
HINTS TO OPTIMIZE THE SEPARATION
Tip 35: Which is the right injection technique to get sharper peaks?
Tip 36: My peaks appear too early – how can I move them in an RP system to later retention times?
Tip 37: How can I increase the plate number?
Tip 38: Limit of detectiTip on: how can I see more?
Tip 39: How can I speed up a separation?
Tip 40: How can I optimize a separation?
Tip 41: Dead volume, capacity factor, selectivity – how can I use them in every day life?
Tip 42: Which flow is optimal for me?
Tip 43: How can I optimize a gradient elution?
Tip 44: Separation of ionic solutes: what works out best – endcapped phases, inert phases, phosphate buffer or ion pairing reagents? Part I
Tip 45: Separation of ionic solutes: what works out best – endcapped phases, inert phases, phosphate buffer or ion pairing reagents? Part II
RETENTION OF IONIZIBLE COMPONENTS IN REVERSED–PHASE HPLC
John F. Kennedy, Carbohydrate Polymers, 2004, Vol. 55