Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo , CEP 14040-903, Ribeirão Preto, SP, Brazil.
Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo , CEP 14040-901, Ribeirão Preto, SP, Brazil.
Anal Chem. 2017 Apr 4;89(7):3929-3936. doi: 10.1021/acs.analchem.6b02855. Epub 2017 Mar 22.
The potential of copper(II) to induce gas-phase fragmentation reactions in macrotetrolides, a class of polyether ionophores produced by Streptomyces species, was investigated by accurate-mass electrospray tandem mass spectrometry (ESI-MS/MS). Copper(II)/copper(I) transition directly induced production of diagnostic acylium ions with m/z 199, 185, 181, and 167 from α-cleavages of [macrotetrolides + Cu]. A UPLC-ESI-MS/MS methodology based on the precursor ion scan of these acylium ions was developed and successfully used to identify isodinactin (1), trinactin (2), and tetranactin (3) in a crude extract of Streptomyces sp. AMC 23 in the precursor ion scan mode. In addition, copper(II) was also used to induce radical fragmentation reactions in the carboxylic acid polyether ionophore nigericin. The resulting product ions with m/z 755 and 585 helped to identify nigericin in a crude extract of Streptomyces sp. Eucal-26 by means of precursor ion scan experiments, demonstrating that copper-induced fragmentation reactions can potentially identify different classes of polyether ionophores rapidly and selectively.
采用精确质量电喷雾串联质谱（ESI-MS/MS）研究了铜（II）诱导大环状聚醚离子载体（一类由链霉菌属产生的聚醚离子载体）在气相中发生碎片化反应的潜力。铜（II）/铜（I）的直接转换会直接诱导[大环聚醚+Cu]的α-裂解，生成具有 m/z 199、185、181 和 167 的诊断酰基阳离子。基于这些酰基阳离子的前体离子扫描，建立了一种 UPLC-ESI-MS/MS 方法，并成功地用于在链霉菌属 AMCC23 的粗提物中对异二氮菌素（1）、三氮菌素（2）和四氮菌素（3）进行鉴定。此外，铜（II）还可用于诱导羧酸型聚醚离子载体尼可霉素的自由基碎裂反应。在链霉菌属 Eucal-26 的粗提物中，通过前体离子扫描实验得到的 m/z 为 755 和 585 的产物离子有助于鉴定尼可霉素，这表明铜诱导的碎裂反应有可能快速、选择性地鉴定不同类别的聚醚离子载体。
