https://www.waters.com/nextgen/nl/en/library/application-notes/2009/increasing-sensitivity-of-bioanalytical-assays-utilizing-microbore-uplc-and-tandem-quadrupole-mass-spectrometry.html
This application note describes the gains in sensitivity using 1 mm I.D. columns compared to 2.1 mm columns when analyzing ibuprofen in human urine.
bioanalytical assaysincreasingsensitivityuplctandem