A coumarin‐based fluorescent probe containing both acrylate moiety and an allyl substituent was developed for distinguishing cysteine from homocysteine. The maximum absorption wavelength of the probe showed a bathochromic shift upon addition of cysteine and the colour changed from colourless to yellow. The maximum fluorescence emission at 462 nm of the probe was dramatically enhanced upon addition of cysteine in aqueous solution. In HEPES buffer (pH = 7.4, EtOH/H₂O = 9:1, v/v), both of the fluorescence emission bands of the probe at ca. 390 and 462 nm were intensely enhanced upon the addition of cysteine, while other amino acids, namely, homocysteine, asparaginic acid, methionine, glycine, phenylalaninase, valine, tryptophan, serine, glutamic acid and glutathione, did not cause a remarkable change. The probe can be used for selectively colorimetric and ratiometric fluorescent detection of cysteine over homocysteine and other common amino acids in both organic media and aqueous solution. The concentration of cysteine can be estimated by titration of the probe in aqueous solution, and the detection limit of the probe towards cysteine was 2 μmol/L.

中文翻译：

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一种基于香豆素的新型荧光探针，可选择性检测同型半胱氨酸上的半胱氨酸

开发了一种同时包含丙烯酸酯部分和烯丙基取代基的基于香豆素的荧光探针，用于区分半胱氨酸和高半胱氨酸。探针的最大吸收波长在加入半胱氨酸后出现红移，颜色从无色变为黄色。在水溶液中添加半胱氨酸后，探针在462 nm处的最大荧光发射显着增强。在HEPES缓冲液（pH = 7.4，EtOH / H ₂ O = 9：1，v / v）中，探针的两个荧光发射带在大约。加入半胱氨酸后强烈增强了390和462 nm，而其他氨基酸，即高半胱氨酸，天冬酰胺酸，蛋氨酸，甘氨酸，苯丙氨酸酶，缬氨酸，色氨酸，丝氨酸，谷氨酸和谷胱甘肽则没有明显变化。该探针可用于在有机介质和水溶液中对同型半胱氨酸和其他常见氨基酸进行选择性比色和比例荧光检测。半胱氨酸的浓度可以通过在水溶液中滴定探针来估计，并且探针对半胱氨酸的检出限为2μmol/ L。