Hue_v: A Tunable Hue Descriptor for the Quantitative Analysis of Multicolor Optical Sensors

Hue-changed sequences of multicolor optical sensors are diverse, whereas hue-quantified sequences of existing quantitative parameters are fixed. Monotonic calibration is unavailable when the two sequences are inconsistent. To overcome this challenge, a hue descriptor named Hue_v was designed. Its quantification sequence is tunable via a parameter named HT. Furthermore, a method of calculating the optimal HT for each sensor, a Hue_v-based analytical workflow (including chemical imaging), and a user-friendly analytical platform were developed. We demonstrated that Hue_v has broader applicability than some existing parameters, calibrated a sensor that cannot be calibrated by existing parameters, transformed qualitative test strips into quantitative tools, and developed a pH imaging method with a broader detection range (0.1-12) than conventional methods. Our work makes it possible to develop a hue-changed phenomenon into a universal optical sensing technique. It promises broad applications in many fields based on analytical chemistry such as point-of-care testing (POCT) and chemical imaging.