Determination of Melatonin in Cow's Milk by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

The aim of the present study is the development of a rapid and accurate analytical method to determine melatonin in milk. In this method, melatonin extracted from milk with ethyl acetate, after application of reversed phase liquid chromatographic separation melatonin, was detected and quantified with tandem mass spectrometry. Performance of method was tested by conducting method validation study wherein limit of detection, limit of quantification, linearity recovery, and precision parameters were determined. Limit of detection and limit of quantification were calculated as 0.016 and 0.054 mu g/kg, respectively. Recovery of the method was checked at two different concentration namely 0.5 and 2.5 mu g/kg and determined as 106 and 100%, respectively. Precision of the method was determined as interday and intraday precision. Intraday precision calculated as 3.92 and 2.15% for 0.5 and 2.5 mu g/kg spike levels. In this study, we describe an analytical method for determination of melatonin in milk with LC-MS/MS. This method offers an efficient, rapid, and easy sample preparation procedure with high selectivity and good sensitivity for the determination of melatonin in milk.