I have recently switched to 100% acetonitrile to prepare my calibration standard (10 mM) spiked with 100 uM of d7-Butyric acid. Somehow, my blank with 100% acetonitrile shows a sharp peak for the d7 but the calibration standard does not show any peak for internal standard and has more than usual noise in the chromatogram.

I am very worried and am here to learn some answers, thanks!