Fine chemical manipulations of microscopic liquid samples. 2. Consuming and nonconsuming schemes.
Fine chemical manipulations of microscopic liquid samples. 2. Consuming and nonconsuming schemes.
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微观液体样品的精细化学操作。
DOI：
10.1021/ac9813989
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发表时间：
1999
影响因子：
7.4
通讯作者：
Gratzl,M
中科院分区：
文献类型：
--
作者：
Lu,H;Matsumoto,T;Gratzl,M
使用合适的扩散微滴管（DMB）可以对微小的液体颗粒进行化学操作，其微小的尖端插入扩散膜作为一个明确的扩散传递通道。在这项工作的第1部分（Gratzl等人）。化学。1999,71,2751−2756)，我们讨论了最简单的基于dmb的操作：加法，即在液滴上加载一种化学物质，该化学物质在液滴上积累而不发生任何化学反应。由于在此过程中，目标液滴中所递送的分子不会被消耗，因此加法是一种非消耗方案。在这项工作中，探索了另一种非消耗方案，即通过DMB从液滴中减去物质。这一过程在宏观化学操作中没有可比性。当扩散在DMB针尖内处于准稳态时，加减均按指数渐近过程进行。在荧光显微镜下，利用荧光染料Lucifer Yellow CH的微观量的运输来表征这些非消耗操作。化学操作的第三种基本类型是DMB输送的物质通过快速化学反应在目标液滴中瞬间消耗。通过将EDTA输送到含有Pb2+离子和颜色指示剂的液滴中来研究这种消耗方案。这些微观滴定监测使用灰阶透过率图像的液滴作为记录与时间。提出了三种基本DMB操作的统一理论。
Microscopic liquid particles can be manipulated chemically using a suitable diffusional microburet (DMB), whose tiny tip plugged with a diffusion membrane acts as a well-defined diffusional transfer channel. In part 1 of this work (Gratzl et al.Anal. Chem.1999,71, 2751−2756), we discussed the simplest DMB-based operation: addition, i.e., loading a droplet with a chemical that accumulates there without any chemical reaction occurring. Since in this process no consumption of the delivered molecules in the target droplet takes place, addition is a nonconsuming scheme. In this work, another type of nonconsuming scheme is explored, which is the subtraction of a substance from droplets via a DMB. This process has no analogy among macroscopic chemical operations. Both addition and subtraction occur according to an exponential asymptotic process when diffusion is at quasi-steady state inside the DMB tip. These nonconsuming operations were characterized using the transport of microscopic quantities of Lucifer Yellow CH, a fluorescent dye, under a fluorescent microscope. The third basic type of chemical manipulation is when the substance delivered by a DMB is consumed in the target droplet instantaneously by a fast chemical reaction. This consuming scheme was studied by delivering EDTA into droplets containing Pb2+ions and a color indicator. These microscopic titrations were monitored using gray scale transmittance images of the droplets as recorded versus time. A unified theory of the three basic DMB operations is also presented.