Pharmaceutical analysis by supercritical fluid chromatography: Optimization of the mobile phase composition on a 2‐ethylpyridine column

Abstract

The separation of neutral, acidic, and basic pharmaceuticals with diverse physicochemical properties by packed column supercritical fluid chromatography (pSFC) on a 2-ethylpyridine column (25 cmx4.6 mm id, 3 mum particles) is presented. The optimization strategy involved separations at 100% methanol (MeOH) and at 50% MeOH/50% ACN while keeping the peak symmetry additives formic acid (FA) and isopropylamine (IPA) at constant levels of 0.25% v/v. By plotting the adjusted retention times as a function of the MeOH/ACN ratio, an optimal modifier ratio composition of 65% MeOH/35% ACN was found. The total set of 26 neutral, acidic, and basic pharmaceuticals was analyzed and the optimal composition experimentally verified. This mobile phase composition is currently used in pharmaceutical method development and open-access generic screening environments.

Theory and Practice of UHPLC and UHPLC–MS

“…In this set up, a lower percentage of organic modifier resulted in higher response (Brunelli et al, 2007). Pre-BPR coupling nebulization happens in the nebulization chamber, and a higher percentage of organic modifier was found to be more convenient for the best sensitivity (Bu et al, 2016;Swartz et al, 2009).…”

“…To obtain a uniform response in gradient elution, it is beneficial to use gradient compensation, similar to what is sometimes employed in HPLC (Bu et al, 2016;Brunelli et al, 2007).…”

“…However, its performance in SFC was found to be substantially worse compared to alcohols, resulting in low efficiency and poor peak symmetry, probably because of low coverage of free silanols (Zou et al, 2000). An interesting solution to obtain different selectivity without sacrificing the performance and peak shapes was observed when using a mixture of methanol and acetonitrile as the organic modifier (Brunelli et al, 2008b).…”

Evaluation of stationary phases packed with superficially porous particles for the analysis of pharmaceutical compounds using supercritical fluid chromatography

“…Utilizing additives in the SFC mobile phase tends to improve both peak shapes and separations of many problematic compounds [1,5,[52][53][54][55]. In the last few years, it has been demonstrated that the addition of ammonium hydroxide was beneficial for H. Fig.…”

“…ultra-fast separations using ballistic mobile phase gradients without a significant loss of chromatographic efficiency. Compressed carbon dioxide (CO 2 ) mixed with an organic modifier (typically an alcohol) is the most common mobile phase for SFC and offers a broad range of conditions suitable for separating a wide variety of polar and non-polar compounds [5][6][7][8][9][10][11][12][13]. SFC is considered to be thermodynamically comparable to liquid chromatography (LC), offering complementary selectivity based on stationary phase chemistry, mobile phase (organic solvents and additives), pressure, and column temperature.…”