By Anonymous on Saturday, September 20, 2003 - 10:19 am:
Hi
1) What are the pros and cons, if any, on solvents mixing between by high and by low pressure pumps and its effect on liquid chromatography performance?
2) Are there any performance mixture specific to a LCMS system for monitoring peak symmetry, sensitivity, resolution etc. The current commercial test mixture seems to lean towards HPLC with non-mass spectrometric detector.
By MG on Tuesday, September 23, 2003 - 07:59 am:
1) There was a post on this not too long ago. Try searching the forum. My understanding is that with low pressure mixing, there's a greater chance to get bubbles in the pump.
2) I don't know of any standard mixtures used to check column performance with MS detection. If you find any, please post them here. If I am using a column only for a specific assay, then a standard mix of the analytes provides all the measure of column performance I need. If you have an APCI or APPI source, you might be able to ionize the (usually neutral) compounds in the column manufacturer's test mix.