Determination of Dicyandiamide in Milk Powders Using Ultra Performance Liquid Chromatography Tandem Mass Spectrometry

Abstract

Dicyandiamide,as a new contaminant in milk powders,can lead to harmful effects to human health,especially to infants and young children. A rapid and accurate method for the determination of dicyandiamide in milk powders using ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry( UPLC-ESI-MS / MS) was established. The milk powders samples were extracted by acetonitrile which contained 2% NH4OH solution( V / V),the separation was carried out using an UPLC BEH HILIC( 150 mm × 2. 1 mm,1. 7 μm) column,10 mmol / L ammonium formate / formic acid buffer( pH 4. 0)and acetonitrile as the mobile phases,gradient elution. The dicyandiamide was detected by ESI+under selected ion monitoring mode. The quantified concentration range was 5-200 μg / L using matrix-matched calibration curves. When applying this method to determine real milk powder samples,the detection limits was10 μg / kg. The recoveries were 83. 7%,89. 1% and 96. 7% respectively when spiked negative samples with50,100 and 200 μg / kg dicyandiamide,and the relative standard deviations were less than 2%. This method is rapid,accurate,highly sensitive and suitable for the determination of dicyandiamide in milk powders.