Analysis of Navel Orange Juice Components by Wooden-Tip Electrospray Mass Spectrometry

The chemical components of navel orange juice were analyzed by wooden-tip electrospray ionizaion mass spectrometry (wooden-tip ESI-MS) without any sample pretreatment. The results show that signals of choline, proline, glucose and sucrose are rapidly obtained in positive ion detection mode. Among them, choline and proline give a signal of M+H⁺, and glucose and sucrose produce a signal of M+K⁺. While in negative ion detection mode, organic acids including fatty acid, phenolic acids and hydroxyl acids are readily detected. Meanwhile, wooden-tip ESI-MS is developed for semi-quantification determination of ascorbic acid in navel orange juice. The limit of detection (LOD) is 3.7 μg/L, the relative standard deviations (RSD) are 7.4%-9.7%, and the analytical time of each detection is less than 0.5 min. Wooden-tip ESI-MS has the advantages of minor or no sample pretreatment, convenient operation, sensitivity and high analytical speed, which will being an attractive method to rapidly screen the quality of agricultural products.