Automated adjustment of capillary voltage based on the elution conditions to retain optimal ionization conditions

摘要

A method of electrospray ionisation is disclosed comprising: passing a sample liquid through a liquid chromatography column 3; monitoring the liquid chromatography back pressure; and varying a voltage applied to an electrospray capillary 4 in dependence upon said measured back pressure, preferably so as to optimise ionisation conditions throughout a liquid chromatography separation experiment. The back pressure in liquid chromatography systems is already routinely monitored and can be used to provide real-time information about conditions within the chromatography column. For example, the back-pressure is related to the viscosity of the mobile phase within the column, the composition of which may vary during the course of an experiment as the ratio of a plurality of solvents is changed. The relationship between the monitored backpressure and electrospray voltage can be fixed, e.g. by an initial calibration run, or may be updated periodically during subsequent chromatography runs.