Project Title

Determining the Optimal Compressibility Factor for Ultra HPLC

Academic department under which the project should be listed

Department of Chemistry and Biochemistry

Research Mentor Name

Dr. Marina Koether

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%.

Disciplines

Analytical Chemistry

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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%.