Ethyl lactate as an environmentally friendly HPLC mobile-phase modifier in the analysis of acetaminophen, caffeine, and ASA

Abstract

Ethyl lactate (EL) has been investigated as an environmentally friendly organic modifier for use in HPLC mobile phases. EL shows significant promise in this regard when used under optimal conditions. In conjunction with a standard C18 column at a temperature of 60 °C, a mobile phase composed of 87% water, 10% EL, and 3% acetic acid is capable of baseline resolution of three standard pharmaceutical analytes (acetaminophen, caffeine, and acetylsalicylic acid) in under three minutes. This same mobile phase was found to be capable of extraction of these same analytes from consumer pain relief tablets with essentially 100% efficiency. Using a core-shell C18 column at 40 °C, similar resolution and run times with these analytes are possible using the same mobile phase but with a reduced EL content of only 2.5%.