ABSTRACT
The coupling of liquid chromatography (LC) with mass spectrometry (MS) has undergone much evolution since its initial inception [1,2]. Atmospheric pressure ionization techniques such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) opened the door for the ionization and analysis of nonvolatile or thermally labile analytes. This technique revolutionized drug discovery and development allowing for dramatic improvements in sensitivity, selectivity, and speed. This area continues to grow, and signi cant advances have been and continue to be achieved in all three areas [3-5].
