Photocolorimeter calibration features

The paper considers the procedure of photocolorimeter calibration using the example of measuring the mass concentration of total iron in water. The color intensity of the solution, proportional to the mass concentration of iron, is measured using a photocolorimeter at a wavelength of 400–430 nm. The main steps of photocolorimeter calibration are: preparation of calibration solutions; measuring the concentration of calibration solutions with a photocolorimeter, obtaining the calibration dependence; identification of the calibration dependence; using the calibration dependence to find the concentration of the test solution of total iron in water. To obtain calibration solutions, the state standard sample is used, which is diluted with water using pipettes and measuring flasks to the required concentration. The uncertainty of identification of the calibration dependence and its use for finding the concentration of the studied solution of total iron in water is evaluated.