Chromatography Forum

Hello Everybody;
how are you today? I hope you are doing well.

since some time we have problem with quetiapine carry-over. Due to the need to analyze impurities in quetiapine which is our API, we must achieve a very low LLOQ. unfortunately, quetiapine shows high carry-over between samples and affects the attenuation of the signal of contamination, which has a very similar retention time. The question is short: what should we rinse the LC-MS/MS system with to get rid of quetiapine? any suggestion is very welcome .

(1) THE HPLC system (column etc) should and must always be rinsed/flushed down with an appropriate solvent solution. An "appropriate" solution is one that dissolves ALL of your samples, 100%, all of the time AND is fully compatible with your column and HPLC system. This insures no material is left on the column (or in the system) after use. The "best" solution to use will be different for each method. It depends on what YOUR sample(s) are. *If you fail to develop proper HPLC system wash methods that rinse off the system after use, then column fouling, MS source cell and detector and/or carry over contamination are the result(s).
(2) Carryover contamination is a result of using poor quality methods And/Or not servicing your HPLC system on a regular basis. Please refer to this free authoritative article to learn more about carry over and how to prevent it: "Carry-Over (Carryover) Contamination in HPLC and LC-MS Systems"; https://hplctips.blogspot.com/2015/02/c ... on-in.html