Thomas J-P, Bejjani A, Nsouli B, Gardon A, Chovelon J-M
IPNL, Université de Lyon, Université Lyon 1, CNRS/IN2P3, 4 rue E. Fermi, 69622 Villeurbanne cedex, France.
Rapid Commun Mass Spectrom. 2008 Aug;22(16):2429-35. doi: 10.1002/rcm.3628.
We have previously demonstrated that PD-TOFMS (plasma desorption time-of-flight mass spectrometry) analysis is a powerful technique for the in situ analysis of pesticides deposited or adsorbed on solid materials. With the aim of producing reproducible data on the modification of a pesticide under controlled photodegradation conditions, we have now undertaken a study where both the substrate and the pesticide are well characterized. This is the case for norflurazon deposited onto an aluminium substrate, in particular regarding the reproducibility of preparation of the samples and the change with time of their chemical composition. Degradation parameters have been derived from the variation in yield of ions representative of the molecule and of its breakdown products and, particularly, from the time required for 50% dissipation of their initial concentration (DT50). DT50 values ranging between 1 and 10 h have been found. An interpretation of the degradation process is proposed from the decay of other ions. As expected, the degradation is faster when the UV sunlight is unfiltered (a factor of 3.8 for the molecule, and around 5 for the breakdown products).
我们之前已经证明，等离子体解吸飞行时间质谱（PD - TOFMS）分析是一种用于原位分析沉积或吸附在固体材料上农药的强大技术。为了在可控的光降解条件下获得关于农药改性的可重复数据，我们现在开展了一项研究，其中底物和农药都得到了很好的表征。对于沉积在铝基板上的氟草敏来说就是这种情况，特别是在样品制备的可重复性及其化学成分随时间的变化方面。降解参数是从代表分子及其分解产物的离子产率变化中得出的，特别是从其初始浓度50%消散所需的时间（DT50）得出的。已发现DT50值在1至10小时之间。根据其他离子的衰减情况对降解过程进行了解释。正如预期的那样，当未过滤紫外线阳光时，降解速度更快（分子降解速度快3.8倍，分解产物快约5倍）。
