When using the LC-MS/MS system to dertermine CPs compounds, I observed a problem that when the standard is prepared in Methanol:Water 1:1 solution, the system gives no result of analyte. However, when I prepared the standard in only water, the separation is quite good and peaks are observed clearly. Please explain
My mobile phase: MeOH:Water
Standard: Phenol mix 604
What is the MeOH:H2O ratio in the eluent? If you inject the sample in liquid having higher elution power that the eluent you can get a shift in the retention time to lower values.
Regards
GB
A typical effect of to high elution power of the injection solvent. Try a lower MeOH ratio - e.g. by diluting your sample until your analytes are bound to the column. good luck
What is your gradient? I bet you are starting with a lower than 50% MeOH in your gradient whereas your sample is in 50% MeOH. Try to match the % or organic to the initial % of the organic in the gradient.
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