Abstract:N-Acetylglucosamine has been confirmed as a distinctive non-protein biomarker for goat milk and cow milk.Based on this foundation,this study established a liquid chromatography-tandem mass spectrometry（LC-MS/MS）method for the quantitative detection of cow milk adulterated in goat milk.The pretreatment process of this method was straightforward,with a total analysis time of approximately 25 min per sample.It exhibited a good linear relationship within the cow milk addition range of 3% to 90%（Y=36 154X+65 152）,with a correlation coefficient of 0.998 5.The limit of detection（LOD）and limit of quantification（LOQ）of the method were 0.9% and 3.0%,respectively（calculated based on the addition level of cow milk）.Additionally,the method demonstrated high accuracy（ranging from 97.9% to 101.6%）and precision（ranging from 2.4%to 5.2%）.