Hydrophilic Interaction Liquid Chromatography Tandem Mass Spectrometry Method for the Determination of Bicozamycin in Milk

A fast and simple method for the quantitative determination of bicozamycin (BCM) in milk samples by hydrophilic interaction liquid chromatography with electrospray tandem mass spectrometry (HILIC-ESI-MS/MS) and centrifugal ultrafiltration (CUF) was presented. The milk sample was extracted with an acetonitrile/water (4/1, v/v) and CUF procedure. After preparation, the sample solution was directly injected onto the HILIC-MS/MS. Chromatographic separation of the components was performed on a TSK-GEL NH2 column using 50mM ammonium acetate in water (pH 4.0 adjusted with acetic acid) and acetonitrile. The mass spectrometer was operated in the negative ESI-MS/MS mode (m/z 301209). The LOD and LOQ were 2.5ng/mL (25pg) and 5ng/mL, respectively. This method was validated according to the Japanese maximum residue limit (0.1 mu g/g) of BCM. The matrix matched calibration of BCM was linear over the calibration range from 50 to 500ng/g (r2=0.999). Recovery values were from 82.6 to 109.9% (RSD 7.5%, n=27). The present method could be applied to measure BCM in milk samples.