Attention has been paid to decrease chemical waste in analytical process. This leads to downscaling chemical analysis [1] and [2]. An interesting property of a liquid drop may refer to constant volume which should be due to adhesive force among the liquid molecules. A liquid drop which poses around 3–50 µL in volume should be readily available for micro scale chemistry manipulation. There have been some reports for such purpose, such as using a liquid drop as interfacing system for gas sampling and analysis [3], [4] and [5], and a windowless spectrophotometric system [6]. Moreover, a falling liquid drop has been proposed to function as a sample introduction to a capillary electrophoresis system [7]. In addition, titration in liquid drop has been explored for acid–base neutralization [8] and complexometric titration of calcium [9] and [10].