Method for liquid chromatographic mass spectrometry and liquid chromatograph mass spectrometer

Abstract

In an LC/MS analysis of a sample containing various compounds, additive supply pumpsA andB in a post-column adding unitdraw and supply different kinds of additives A and B from containersA andB, respectively. The additives are mixed into an eluate through T-jointsand. A preferable combination of the additives is the combination of DMSO which produces the effect of gathering charge states and 2-propanol which produces the effect of promoting atomization or vaporization of droplets. By mixing the two additives into the eluate while mixing them at an appropriate flow-rate ratio according to a previously determined flow-rate program, the ionization efficiency can be nearly optimized for each compound during the process of generating ions by spraying electrically charged droplets of the eluate from an ESI spray. Consequently, the detection sensitivity becomes higher than conventional levels.