Determining the Optimal Compressibility Factor for Ultra HPLC
Disciplines
Analytical Chemistry
Abstract (300 words maximum)
Liquid compression occurs due to the high pressure applied to the mobile phase in ultra HPLC. If this compression is left uncorrected, pump pressure ripples occur and affect flow rate, baseline stability, and increases pump noise. Each solvent has a compressibility value; mixtures of solvents require the averaging of these values. However, the best value is only found via experimentation. Three-point calibration curves using the middle point as the unknown were analyzed at several compressibility factors. The lowest percent error from the accepted concentration value as well as the lowest standard deviation obtained were used to determine the best compressibility factor. Determining the compressibility factor is one of the first steps that is required in developing an HPLC method. Analysis of ethylparaben using a 50:50 water: acetonitrile mobile phase resulted in an optimized compressibility factor of 0.82, giving a percent error and standard deviation of 0.78 % ± 0.06%.
Academic department under which the project should be listed
Department of Chemistry and Biochemistry
Primary Investigator (PI) Name
Dr. Marina Koether
Determining the Optimal Compressibility Factor for Ultra HPLC
Liquid compression occurs due to the high pressure applied to the mobile phase in ultra HPLC. If this compression is left uncorrected, pump pressure ripples occur and affect flow rate, baseline stability, and increases pump noise. Each solvent has a compressibility value; mixtures of solvents require the averaging of these values. However, the best value is only found via experimentation. Three-point calibration curves using the middle point as the unknown were analyzed at several compressibility factors. The lowest percent error from the accepted concentration value as well as the lowest standard deviation obtained were used to determine the best compressibility factor. Determining the compressibility factor is one of the first steps that is required in developing an HPLC method. Analysis of ethylparaben using a 50:50 water: acetonitrile mobile phase resulted in an optimized compressibility factor of 0.82, giving a percent error and standard deviation of 0.78 % ± 0.06%.