▎ 摘　　要

Graphene oxide is a flexible nanoscale building block, which is contributed to improve the electrical, optical, and chemical properties. Here, gold nanoparticles on graphene oxide substrate were synthesized as sensitive nanoprobes for rapid L-cysteine detection. The smartphone-based system with multimode analysis of red-green-blue (RGB), hue-saturation-value (HSV), hue-saturation-lightness (HSL), and cyan-magenta-yellow-black (CMYK), were proposed for the investigation of interactions between the nanoprobes and L-cysteine. Then, optical absorption spectra were further examined to confirm the concentration characteristics of L-cysteine. Results suggested that gold nanoparticles on graphene oxide substrate had satisfying linearity and stability in dose-dependent responses to L-cysteine detection in the multimode analysis with the limit of detection at 0.06 mu M. Therefore, the smartphone-based nanoprobes system not only equipped with a high resolution camera and a powerful processor, but also was a fully automated device without additional label or complex detection. These features make it to be a convenient and efficient analysis platform for multiple fields, such as clinical application, industrial quality control, environment monitoring, and food assessment.