Application of the Semi-Automatic Titration Method Using a Webcam for the Determination of Calcium in Milk and Dairy Products

Quantitative determination of calcium content in milk and dairy products is an important analytical task due to the great importance of this element in the human diet. Calcium determination in milk and dairy products was performed using semi-automatic complexometric titration with a webcam as a color change detector. The color changes were registered directly in turbid dairy dispersions, creating a white background. The analytical signals tested were the color component (R, G, B) read from the titration beaker images and the calculated Hue parameter. For the calcein indicator, the optimal signals are Green and Hue. For the HNB indicator, the optimal signals are Red and Hue. The developed method of titration using an RGB camera detector is characterized by excellent linearity (R² = 0.9999) and accuracy. RSD values range from 0.3 to 2.9%. Recovery values range from 105 to 113%. Examples of calcium determination in commercial products include milk, fermented products, cream, and cottage cheese.