Simultaneous analysis and measurement of uncertainty estimation of six isoflavones in Cheonggukjang by liquid chromatography-electrospray tandem mass spectrometry

Abstract A novel and simple method for detecting six isoflavones in Cheonggukjang using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) was developed. The method validation was performed in terms of linearity, sensitivity, selectivity, accuracy and precision. The limits of detection (LODs) for the instrument employed in these experiments ranged from 0.15 μg/kg to 1.50 μg/kg, and the limits of quantification (LOQs) ranged from 0.50 μg/kg to 5.00 μg/kg. The average recoveries of the six isoflavones ranged from 82.3% to 98.9%. Before assessing the uncertainty of the measurements, we identified the factors that affect the measured value using quantitative analysis to determine how each factor affects the measurement result. It was found that the sample weighing, standard material purity, dilution, calibration curve and reproducibility factor affect the uncertainty of measurement. The developed method was specific and reliable. Therefore, the method is suitable for the routine analysis of isoflavones in Cheonggukjang.