Effect of temperature on the measurement of dissolved oxygen in the package.

The article deals with the measurement of dissolved oxygen in beverages using electronic probe and the influence of time and temperature changes on the result of measurement in a sample standing at a rest. The content of dissolved oxygen in the water depended on the temperature even with the constant concentration of dissolved oxygen in the sample, without any exchange of oxygen between gaseous and liquid phase. With the drop in water temperature the displayed DO increased while it decreased with increasing temperature. The difference of dissolved oxygen due to temperature changes was lower than it would correspond to the difference in solubility of oxygen. Speculative explanation of this phenomenon assumes the existence of microbubbles of oxygen dispersed in the liquid. For the analysis of samples is therefore advisable to determine the permissible time between sampling and analysis. The time between sampling and analysis should not be longer than 2 h.The article deals with the measurement of dissolved oxygen in beverages using electronic probe and the influence of time and temperature changes on the result of measurement in a sample standing at a rest. The content of dissolved oxygen in the water depended on the temperature even with the constant concentration of dissolved oxygen in the sample, without any exchange of oxygen between gaseous and liquid phase. With the drop in water temperature the displayed DO increased while it decreased with increasing temperature. The difference of dissolved oxygen due to temperature changes was lower than it would correspond to the difference in solubility of oxygen. Speculative explanation of this phenomenon assumes the existence of microbubbles of oxygen dispersed in the liquid. For the analysis of samples is therefore advisable to determine the permissible time between sampling and analysis. The time between sampling and analysis should not be longer than 2 h.