科研之友
微信
新浪微博
Facebook
分享链接
摘要
Three TLC methods were used for an initial screening of some common plant triterpenoids and phytosterols in cuticular wax extracts of different vegetables (zucchini, eggplant, tomato, red pepper, mangold, spinach, lettuce, white-colored radicchio di Castelfranco, raddichio Leonardo, white cabbage, red cabbage and savoy cabbage). The preliminary experiments showed that the studied vegetables are potential sources of triterpenoids and phytosterols. To identify the compounds present in the extracts with high certainty, the first TLC-MS2 method was developed for the analysis of eight triterpenoids (lupeol, alpha-amyrin, beta-amyrin, cycloartenol, cycloartenol acetate, lupeol acetate, lupenone and friedelin) and two phytosterols beta-sitosterol and stigmasterol). This method takes the advantages of: (1) a satisfactory separation of the target compounds; (2) their differentiation according to the band colors; and (3) the potential of their discrimination by the acquired first-order mass (MS) and product ion (MS2) spectra. Since the closely eluting compounds have complex and similar MS2 spectra, distinguishing between them was possible by the proposed characteristic ions. Using a custom-built mass spectral library, the head to tail MS2 spectra comparison of sample test solution zones and standard aided the compound identification. In addition to the molecular mass information, the developed atmospheric pressure chemical ionization method (APCI) in positive ion mode provided structural information, regarding the presence of functional group in the molecule. This approach resulted in many positively assigned compounds in the investigated vegetable waxes, from which more than a half are reported for the first time.
- 出版日期2015-2-13
