The Altis Plus is a high-performance triple stage quadrupole mass spectrometer and is used predominately for selected reaction monitoring (SRM) experiments. It includes a syringe pump, a divert/inject valve, an atmospheric pressure ionisation (API) source, and the Xcalibur™ data system. You can operate the mass spectrometer in either electrospray ionisation (ESI), atmospheric pressure chemical ionisation (APCI) and Atmospheric Pressure Photo ionisation (APPI) modes. Typically, polar compounds such as amines, drugs and small peptides are best analysed by ESI, and non-polar compounds such as steroids are best analysed by APCI or APPI.
With ESI, the Altis Plus can quantitively analyse 100’s of compounds within a single UPLC run and is especially useful for quantitative analysis of polar compounds, which include biological analytes; pharmaceuticals and their metabolites. Like ESI, APCI and APPI are soft ionization techniques. APCI provides molecular weight information for compounds of low polarity that are somewhat volatile. APCI is typically used to analyse small molecules with molecular weights up to about 1000 amu.