Buffer vs. water = no signal vs. signal?
Hi everybody!Has any of you experienced a similar problem or have a comment regarding the one outlined below: 1) When I dissolve my substance of interest (little and polar) in waterand use my UPLC-MS/MS (Xevo TQ MS) machinery I can measure my substance at nM scale. 2) When I dissolve same substance inphosphate buffer (0.1 mM, pH adjusted to 7.4) and run upon the same machinery and with same eluent as above I get no signal at all! Both 1 and 2 was run at same time. 3) When I dissolve same substance in water and run it upon my HPLC-MS/MS (Quatro Micro) machinery (same eluent) I can measure my substance at nM scale. 4) When I dissolve same substance in phosphate bufferand run it upon my HPLC-MS/MS (Quatro Micro) machinery I can measure my substance at nM scale. I am really puzzled, as I have checked for matrix effect (which seems much the same for buffer and water injection at retention time). Any answer will do.Best regards, Kasper