EVALUATION OF MOBILE PHASE ADDITIVES AND TEMPERATURE ON COLUMN LIFETIME FOR HIGHPERFORMANCE LIQUID CHROMATOGRAPHY

Buffered solutions, additives, and column temperature are widely used in high-performance liquid chromatography to promote adequate retention of compounds and to improve the chromatographic separation. However, these factors can dramatically reduce the column lifetime. In this work, the effect of column temperature, pH and the salt type and concentration in buffered mobile phases were evaluated on the stability of a typical commercial C18 stationary phase. A method for rapid evaluation of stationary phase degradation caused by these variables was employed to avoid the generation of large volumes of organic waste. By monitoring the performance of stationary phase in the separation of a standard test mixture, it was possible to verify that the pH of the mobile phase is the most drastic condition to reduce the column lifetime. Buffer solutions of inorganic salts as well as the use of temperatures above 40 °C also significantly reduce the column lifetime. However, a column can have its use extended working with low concentrations of organic additives in the mobile phase, under moderated temperature, and adjusting the pH to the safety range of silica-based materials.