Chemistry Department, ETSEA, University of Lleida, 25198, Lleida, Spain.
Chemistry Department, ETSEA, University of Lleida, 25198, Lleida, Spain; DATCEM Scientific Technical Services, University of Lleida, 25198, Lleida, Spain.
J Chromatogr A. 2018 Sep 21;1568:69-79. doi: 10.1016/j.chroma.2018.07.016. Epub 2018 Jul 5.
A total of 48 chlorophylls and derivatives were identified and successfully determined in tea and processed vegetable and fruit foodstuff by UHPLC with photodiode-array and mass spectrometry detection. The method allowed the proper separation of chlorophyll derivatives resulting from demetallation, dephytilation, decarbomethoxylation, epimerisation and copperisation. The method was performed in less than 12 min, using an optimised ternary gradient (MeOH, iPrOH, MeCN and HO with 10 mM of ammonium acetate) on an ACQUITY HSS T3 column. Mass spectrometry, applying both ESI and APCI ionization sources, was used for identification purposes. The method was applied to evaluate the degree of processing in teas of different origin and quality. It allowed differentiation between supermarket own-brand tea bags and teas sold by specialised shops. Pheophytins, pheophorbides and pyro derivatives were found mainly in processed green vegetable and fruit products thereof. However, chlorophyll-derived food colorants, such as Cu-chlorophyllins, Cu-pheophytins, Cu-pyropheophytins, Cu-pheophorbides and Cu-pyropheophorbides, were also detected in several products.
总共鉴定并成功测定了 48 种叶绿素及其衍生物，这些物质存在于茶和加工的蔬菜及水果食品中，使用的方法是超高效液相色谱法，检测工具包括光电二极管阵列和质谱仪。该方法可适当分离出脱金属、去植基、脱羧甲氧基、差向异构化和铜化等反应生成的叶绿素衍生物。该方法在 12 分钟内完成，使用的是优化的三元梯度洗脱（甲醇、异丙醇、乙腈和水，其中含有 10 mM 乙酸铵），洗脱液在 ACQUITY HSS T3 柱上进行分离。质谱分析采用电喷雾电离源（ESI）和大气压化学电离源（APCI）两种电离源进行鉴定。该方法应用于评估不同来源和质量的茶叶的加工程度。它可以区分超市自有品牌的茶包和专卖店销售的茶。在加工的绿色蔬菜和水果产品中主要发现了叶绿醇、脱镁叶绿酸和焦脱镁叶绿酸衍生物。然而，在几种产品中还检测到了叶绿素衍生的食品着色剂，如铜叶绿素、铜脱镁叶绿酸、铜焦脱镁叶绿酸、铜脱镁叶绿酸和铜焦脱镁叶绿酸。
