This picture shows urine of different pH values (from the left it starts with a control sample, pH 3; 6.5; 8.5; 9.5 and 11). This experiment is supposed to give some information about the influence of different pH values within the storage of urine and the changes of/influence on nutrient concentrations during the storage. In comparison to the picture from the 22.04.2010 (same set) you see that the colouring has already changed. (Photo by RWTH Aachen, 22.07.2010.)