The design and use of a simple System Suitability Test Mix for generic reverse phase high performance liquid chromatography–mass spectrometry systems and the implications for automated system monitoring using global software tracking

The development of a seven-component test mixture designed for use with a generic gradient and a reversed-phase high performance liquid chromatography–mass spectrometry (RP-HPLC–MS) system is discussed. Unlike many test mixtures formulated in order to characterise column quality at neutral pH, the test mixture reported here was designed to permit an overall suitability assessment of the whole liquid chromatography–mass spectrometry (LCMS) system. The mixture is designed to test the chromatographic performance of the column as well as certain aspects of the performance of the individual instrumental components of the system. The System Suitability Test Mix can be used for low and high pH generic reverse phase LCMS analysis. Four phthalates are used: diethyl phthalate (DEP), diamyl phthalate (DAP), di-n-hexyl phthalate (DHP) and dioctyl phthalate (DOP). Three other probes are employed: 8-bromoguanosine (8-BG), amitryptyline (Ami), and 4-chlorocinnamic acid (4-CCA). We show that analysis of this test mixture can alert the user when any part of the system (instrument or column) contributes to loss of overall performance and may require remedial action and demonstrate that it can provide information that enables us to document data quality control.