Analysis of monoethanolamine by derivatization with Marfey's reagent and HPLC

A sensitive and selective method for determining the residual monoethanolamine in a developmental drug substance is developed and validated. Marfey's reagent, which is commonly used for the chiral analysis of amino acids, is reacted with the primary amine group of monoethanolamine and then analyzed by high-performance liquid chromatography-UV at 340 nm. Quantitation is performed by a standard addition method by preparing drug substance samples with added monoethanolamine ranging from 0.25-1.0 microg/mL (equivalent to 12.5-50 ppm with respect to the drug substance). The method performance is evaluated for linearity, specificity, detection and quantitation limits, accuracy, precision, and sample stability. The method is linear from 0.25-1.0 microg/mL with a coefficient of determination (r(2)) > 0.95. The accuracy and precision obtained is 105.5 +/- 4.8% (n = 3). The limits of detection and quantitation are 0.03 and 0.10 microg/mL, respectively. Instrument precision (% relative standard deviation of six injections of a derivatized 0.5 microg/mL monoethanolamine solution on two separate days) is >/= 2.0%. This method is suitable for the determination of monoethanolamine at the 25 ppm level in drug substance.