Acceleration of reaction in charged microdroplets.
Acceleration of reaction in charged microdroplets.
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DOI：
10.1017/s0033583515000086
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发表时间：
2015-11
影响因子：
6.1
通讯作者：
Zare RN
中科院分区：
文献类型：
--
作者：
Lee JK;Banerjee S;Nam HG;Zare RN
利用高分辨率质谱技术，我们研究了带电电喷雾液滴中异喹啉的合成以及熔融液滴中细胞色素c与麦芽糖的络合作用，以研究液滴驱动反应（包括共价和非共价相互作用）的可行性，其速度比在常规散装溶液中观察到的要快。在这两种情况下，我们都发现了明显的反应加速，前者是一百万倍或更多，后者是一千倍或更多。我们认为在微滴（直径约1-15 μm，相当于0.5 pl - 2 nl）中进行反应是提高反应速率的一般方法。机理目前尚未确定，但液滴蒸发和液滴限制试剂似乎是其中的两个重要因素。在熔融水滴的情况下，在液滴发生融合并进入质谱仪加热毛细管入口的飞行时间内，蒸发已被证明几乎可以忽略不计。这表明：(1)蒸发不是加速液滴熔合过程的原因；(2)液滴-空气界面可能在加速反应中起重要作用。我们认为，这种“微滴化学”可能是一种显著的替代方案，可以加速缓慢和困难的反应，并与质谱相结合，它可能为在受限环境下研究化学和生化反应提供一个新的领域。
Using high-resolution mass spectrometry, we have studied the synthesis of isoquinoline in a charged electrospray droplet and the complexation between cytochrome c and maltose in a fused droplet to investigate the feasibility of droplets to drive reactions (both covalent and noncovalent interactions) at a faster rate than that observed in conventional bulk solution. In both the cases we found marked acceleration of reaction, by a factor of a million or more in the former and a factor of a thousand or more in the latter. We believe that carrying out reactions in microdroplets (about 1–15 μm in diameter corresponding to 0·5 pl – 2 nl) is a general method for increasing reaction rates. The mechanism is not presently established but droplet evaporation and droplet confinement of reagents appear to be two important factors among others. In the case of fused water droplets, evaporation has been shown to be almost negligible during the flight time from where droplet fusion occurs and the droplets enter the heated capillary inlet of the mass spectrometer. This suggests that (1) evaporation is not responsible for the acceleration process in aqueous droplet fusion and (2) the droplet–air interface may play a significant role in accelerating the reaction. We argue that this ‘microdroplet chemistry’ could be a remarkable alternative to accelerate slow and difficult reactions, and in conjunction with mass spectrometry, it may provide a new arena to study chemical and biochemical reactions in a confined environment.