Automated colorimetric analysis in paper based sensors

Recent times have seen a wide ranging and large scale use of paper as a potential material in sensors for determining the concentration of an analyte upon appropriate end-point development. Today´s clinical, food and environmental sectors require low-cost practical analytical devices which are portable and offer on-site real time detection. We present a novel technique for estimating any analyte´s concentration using a mobile app that analyses the image of the paper subsequent to a chromogenic assay. Making use of snakuscules for capturing the region of interest in the image, followed by basic strategies for removing illumination artifacts using the Von-Kries Coefficient Law, we correlated the luminosity of the colour developed on the paper strip against the analyte´s concentration. We evaluate our algorithm by determining the glucose concentration levels in blood using commercially available glucometer strips using image processing and comparing them with actual glucose levels as estimated by auto analyzers. The results obtained correlated well with the conventional assay and were almost indistinguishable from the actual values.