The product is a simple and rapid organophosphorus (OP) compound detection system as shown in Figure 1.0. The detection is based on colorimetric method which incorporated with image processing technique. Obvious color change can be observed after mixing a reagent with the sample. Image of the resulting mixture is captured using a smart phone. The color image is processed to obtain red, green, and blue (RGB) values. The concentration of OP in the sample can be determined using the developed mathematical model. The system is able to detect low level of OP rapidly (within one minute).