The sensitivity of pH indicators is always confined in acidic solvents used during the immobilization because of the large deviation from their color transition points. By regulating the pH of indicators using organic acid or base, the color transition points of indicators could be readily achieved and the sensitivity could be greatly enhanced. In this study, bromophenol blue was selected as an example to interpret this improvement. And Hue, Saturation and Value (HSV) color model was applied to obtain digital color information of pH indicators. In addition, other two kinds of pH indicators were chosen and regulated to their color transition points as well. The resultant indicators together with the original ones were composed to a colorimetric sensor array and utilized to determine fish freshness. Compared with the original indicators, much higher sensitivity in the detection of fish freshness was obtained by the pH regulated indicators.
Wang Shiyu,Zhou Ying,Zhao Wenchang,Li Yanhong,Tang Shuxian,Si Ting,Zhu Pingan
Directional droplet motion on solid surfaces, governed by Gibbs’ theory of minimizing surface free energy, traditionally relies on static surface gradients. However, such approaches face intrinsic constraints, including fixed transport directions and interdependence between transport distance and speed. Here, we introduce shape-evolving microfiber rails (SEMRs) that enable spontaneous droplet transport on initially non-gradient surfaces. Inspired by a domino-like mechanism, the SEMRs dynamically generate cascading gradients through shape deformations in response to droplet-surface interactions, diverging from conventional static-gradient designs. This adaptive strategy allows for steerable droplet motion, independent control over transport distance and velocity, and design flexibility for on-demand performance optimization. The SEMR’s versatility heralds advanced applications across analytical chemistry, cargo transport, electronics, and diagnostics, paving the way for advanced intelligent fluidic systems.
危险品化学品经营许可证（带存储）