The sensitivity advantages of micro-flow liquid chromatography coupled with a mass spectrometer (MFLC-MS/MS) is well known. This signal increase has led to the manufacture of specialized LC pumps that accurately deliver ≤100 mL/min of solvent. In order to compensate for the lower flowrate, columns with an inside diameter of ≤1.0 mm can be utilized. One of the disadvantages of the MFLC-MS/MS is the maximum volume of sample that can be injected onto the system. Traditional HPLC-MS/MS analysis allows for proportional increases in signal when the injection volume is increased to the routine bioanalytical maximum injection volume of 40 mL. The maximum injection volume on a MFLC-MS/MS is ≈10 mL using 10.0 mL/min flowrates on a 0.300 mm ID column. Experiments were conducted to determine the sensitivity gains from MFLC-MS/MS compared to traditional HPLC-MS/MS.