Edible oils, an important raw material in food processing and the main sources for people to intake energy and nutrients in daily life, is too complex to rapid analyze due to its complicated chemical mixtures. Herein, methodology of direct analysis of crude extract of edible vegetable oil and illegal cooking oil using extractive electrospray ionization (EESI) was established. Fatty acids and other substances were directly identified, as well as differences of each kind of quality oil mass fingerprint were characterized in the positive and negative ion detection mode. Combined with principal component analysis (PCA), 20 different brands of cooking oil and five kinds of illegal cooking oil samples were successfully distinguished. Thus this method could distinguish sources of edible oil with high specificity, good accuracy, low false positives (∼ 0%) and rapid analysis (about 2 min), which was expected to be used for fast, effective high-throughput analysis of low-grade cooking oil.

食用油是食品加工中的重要原料，也是人们日常生活中摄取能量和营养的主要来源，由于其化学混合物复杂，难以快速分析。在此，建立了使用萃取电喷雾电离 (EESI) 直接分析食用植物油和非法食用油的粗提物的方法。脂肪酸等物质被直接鉴定，并在正负离子检测模式下表征了每种质量油质量指纹的差异。结合主成分分析（PCA），成功区分了20种不同品牌的食用油和5种非法食用油样品。因此该方法可以区分食用油的来源，特异性高，准确度好，