Multichannel fluorescent sensor array for discrimination of thiols using carbon dot–metal ion pairs

Thiols play an essential role in mediating physiological processes and maintaining balance in biological systems. Therefore, it is of great importance to develop a convenient method for detection and discrimination of thiols. In this work, a facile multichannel fluorescent sensor array was fabricated to detect and discriminate thiols based on carbon dot (CD)–metal ion pairs. The selected metal ions induced aggregation of the CD, and thus quenched their fluorescence. Different thiols exhibited different affinities for the metal ions, resulting in disaggregation or further aggregation of the CD. As a result, the fluorescence of the CD was recovered or further quenched by the addition of thiols, generating distinct fluorescence response patterns. The characteristic response patterns of seven kinds of thiols were differentiated by linear discriminant analysis at a low concentration of 1.0 μM. Moreover, the sensor array was validated by 100% accurate identification of 42 thiols in double-blind experiments, as well as in fetal bovine serum and urine. The present multichannel sensor array possesses a simple fabrication process, and may also be extended to detect and discriminate other analytes with similar chemical structures or properties.