Improvement of chlorophyll identification in foodstuffs by MALDI ToF/ToF mass spectrometry using 1,5-diaminonaphthalene electron transfer secondary reaction matrix
Improvement of chlorophyll identification in foodstuffs by MALDI ToF/ToF mass spectrometry using 1,5-diaminonaphthalene electron transfer secondary reaction matrix
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DOI：
10.1007/s00216-015-8728-9
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发表时间：
2015-08-01
影响因子：
4.3
通讯作者：
Palmisano, Francesco
中科院分区：
文献类型：
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作者：
Calvano, Cosima Damiana;Ventura, Giovanni;Palmisano, Francesco
叶绿素（Chlorophylls，Chls）是藻类和植物叶绿体中重要的绿色色素。在这项研究中，1，5-二氨基萘（DAN）作为电子转移二级反应基质的完整叶绿素及其衍生物的鉴定，基质辅助激光解吸电离（MALDI）质谱（MS）。DAN被证明大大优于常规基质，如α-氰基-4-羟基肉桂酸，地蒽酚，蒽，甚至三噻吩，因为金属离子的损失和植醇酯键的断裂是可以忽略的。叶绿素a和B在m/z分别为892.529和906.513处没有明显的自由基阳离子断裂，使得MALDI MS能够跟踪完整的卟啉基色素的自然降解，其初始步骤仅由脱金属和脱植酸表示。叶绿素的副产品，如焦脱镁叶绿素，已被确定在干茶叶显示MALDI MS的潜力，以下叶绿素生物转化发生在加工食品。最后，初步结果显示了MALDI MS检测非法植物油再绿化做法的潜力。
Chlorophylls (Chls) are important pigments responsible for the characteristic green color of chloroplasts in algae and plants. In this study, 1,5-diaminonaphthalene (DAN) was introduced as an electron transfer secondary reaction matrix for the identification of intact chlorophylls and their derivatives, by matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS). DAN was proved to drastically outperform conventional matrices such as alpha-cyano-4-hydroxycinnnamic acid, dithranol, antracene, and even terthiophene, since loss of the metal ion and fragmentation of the phytol-ester linkage are negligible. Absence of significant fragmentation of radical cations of Chls a and b at m/z 892.529 and 906.513, respectively, makes MALDI MS capable of following natural degradation of intact porphyrin-based pigments whose initial steps are just represented by demetalation and dephytylation. Chl by-products, such as pyropheophytins, have been identified in dried tea leaves showing the potential of MALDI MS to follow chlorophyll biotransformation occurring in processed foodstuffs. Finally, preliminary results show the potential of MALDI MS to detect illegal vegetable oil re-greening practices.