A colorimetric Boolean INHIBIT logic gate for the determination of sulfide based on citrate-capped gold nanoparticles

Herein, we designed a noncommutative logic gate (INHIBIT gate) by utilizing citrate-capped AuNPs as a signal transducer and S2− and TU as mechanical activators and devised a colorimetric sensor for inexpensive, label-free, rapid, sensitive and selective determination of S2−. Under the optimum conditions, 4 μM S2− could induce a significant color change which can be directly recognized by naked eyes. The calibration curve for the absorbance ratios of A680/A520 against S2− concentration was linear in the range from 2 to 9 μM and the RSD was 1.3% for the determination of 4 μM S2− (n = 6). Moreover, this logic gate was successfully applied for sensing S2− in various practical samples, implying its wide applications in food, environment, and biological system.