Coumarin based small molecule 6,7-dihydroxycoumarin or Esculetin (ES) has been used for the colorimetric and fluorogenic detection of trace amount of water in acetonitrile, acetone and 1,4 dioxane. The deprotonated(anionic) form of ES namely ES-F is reprotonated by trace amount of water. It was observed that the compound ES itself act as a water sensor through formation of hydrogen bonding interaction with the water. But, the probe ES-F shows high sensitivity in acetonitrile as low as the limit of detection (0.0167 wt%). ES-F found to be more sensitive for moisture detection as compared ES. Di-hydroxide group present in the ES play an essential role in sensing the moisture in the organic solvent and it was confirmed by a model compound. Further, taking advantage of basic nature of D₂O, compound ES was used as an efficient optical sensor to detect D₂O in organic solvents and H₂O contamination in D₂O. The response mechanism of sensor ES to D₂O is based on deprotonation. The different spectral behaviour of ES with D₂O and water also used to discriminate between D₂O and H₂O. The probe ES has many advantages such as economical, readily available, no multistep chemical synthesis, good sensitivity, fast response and used to discriminate D₂O and H₂O.

基于香豆素的小分子 6,7-二羟基香豆素或 Esculetin ( ES ) 已用于比色和荧光检测乙腈、丙酮和 1,4 二恶烷中的痕量水。ES的去质子化（阴离子）形式即ES -F被微量水重新质子化。据观察，化合物ES本身通过与水形成氢键相互作用而充当水传感器。但是，探针ES-F在低至检测限 (0.0167 wt%) 的乙腈中显示出高灵敏度。与ES相比，发现ES-F对水分检测更敏感。ES中存在的二羟基基团在检测有机溶剂中的水分方面发挥着重要作用，并通过模型化合物得到证实。此外，利用 D ₂ O 的基本性质，化合物ES作为一种高效的光学传感器用于检测有机溶剂中的 D 2 O 和 D 2 O 中的 H _{2 O污染}。传感器ES对 D ₂ O的响应机理为基于去质子化。ES与 D ₂ O 和水的不同光谱行为也用于区分 D ₂ O 和 H ₂ O。探针ES具有经济、易得、无需多步化学合成、灵敏度好、响应快等优点，可用于区分D ₂ O和H ₂ O。