Development of Portable Colorimeter for Detection of Formalin in Fish

Formalin is used as a preservative in fish, as fish is a perishable product. The present study describes the development of a battery-operated portable colorimeter for the on-site determination of formalin in fish. Combining light sources of various wavelengths with an electric circuit and light dependent resistor results in a simple and cost-effective colorimeter. The gadget functions based on the light received by the light-dependent resistor, which is directly linked to the circuit board for resistance measurement using the resistance to absorbance connection and, the resistance values were converted to absorbance. The developed portable colorimeter is calibrated for the quantitative detection of formalin. The device exhibited an efficient detection of formalin at the range of 1 to 20 ppm. The portable colorimeter exhibited high accuracy and the results are promising for on-site detection of formalin in fish.