Rapid screening of low-quality cooking oil by extractive electrospray ionization mass spectrometry

Abstract

• Methodology of direct analysis of crude extract of edible vegetable oil and illegal cooking oil using extractive electrospray ionization (EESI) was established. • Characterized differences of each kind of quality oil mass fingerprint 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 are successfully distinguished. 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.