Method Development of Standard Dilution Analysis

Standard dilution analysis is a novel analytic measurement method employing a combination of internal standard method and standard addition method. Standard dilution analysis has been successfully employed to determine heavy metal concentrations in consumer goods, as well as ethanol concentration in gasoline. This begs the question; can standard dilution analysis provide calibration curves with more precise figures of merit than the external calibration method for molecular targets? Ibuprofen standards and benzoic acid internal standards were prepared, as well as an “unknown” of ibuprofen at a known concentration to test for accuracy of the measurement. Ultra-high-performance liquid chromatography was employed to separate the internal standard benzoic acid from the ibuprofen due to the closeness of the lambda max for the two compounds. The mathematics behind the method and preliminary results will be described including struggles with pipet and volumetric flask precision and accuracy issues