Chromatography Forum

Hai Friends,

I am tried the 300 pesticide compounds through in Phenomenox Aqua C18 Column with ammonium formate, gradient used by LC MS Ms. But 50 compounds no response and 20 compounds very low response in the column. so plz suggest the suitable column for the all pesticide (300 compounds) and mobile phase in single run.

ask whoever told you that you can analyze 300 pesticides in a single LC-MS run without carfully "selecting" the analytes. In the real world, it's close to impossible.

Please don't use some "well-designed" application notes from certain famous instrument manufactures as reference.

ask whoever told you that you can analyze 300 pesticides in a single LC-MS run without carfully "selecting" the analytes. In the real world, it's close to impossible.

Please don't use some "well-designed" application notes from certain famous instrument manufactures as reference.

haha very very true, needed a good laugh thank you Yangz00g! There is no such thing as a simple LC-MS pesticide residue analysis....no matter what!

I tried doing almost 150 pesticides in a single shot on tobacco extracts. Company we work for said it was possible to just shoot them on LCMSMS. After months of development I finally got them to send me their method, which turned out to be an article published by a European research group and found out nearly half were being run GCMSMS. Happens to be the ones I could not get to work were not soluble in water, only toluene, which doesn't work well with an HPLC reversed phase system too well

It is possible if all the pesticides are water soluble, but you will probably have to break it up into positive and negative analytical runs to get them all with good sensitivity. The run that Restek/ABI have done with 300 analytes will work, but it is a bear to get all the MRMs grouped and the transitions from one grouping to the next timed correctly, and if you have any drift in retention times you will have to correct your group timings to compensate.

Doable, but definitely not plug and play.

For your method you will probably need to optimize each analyte individually to get good responses across the board.