urine cortisol interference
We are using the uplc TQD for the analysis of the urine free cortisol. Transition peaks: 121 and 97 are used for the quantification and confirmation. However, in the low concentration urine samples, we always found two or sometimes three interference peaks for both transition peaks. (The standard curve and QC samples are always good and no interference peaks).Those interference peaks do not affect the quantification because they are separated with the transition peaks, but we would like to know what they are. Anyone knows that which compound those interference peaks belong to?