Determination of phosphate phosphorus is an increasingly important measurement today. Environmental engineers consider the measurement of phosphorus in water as phosphate. In particular, the loss of properties of water and inorganic phosphate compounds harm nature. The nutrients required for the development of plants are nitrogen, carbon and phosphorus. Carbon and nitrogen are naturally introduced into water, but the limiting element is phosphorus.

Phosphorus is an important element in the cells and tissues of plants and animals. Phosphorus in water resources in nature is the key element of biological and chemical balance. Phosphorus in the water is found in various halide compounds. Phosphorus reacts in both natural water environments and wastewater environments. A large proportion of phosphorus in lake waters is found in organisms' cells and dead organic matter as organic phosphorus. Total phosphorus concentration is high in polluted waters and marshes. In the mountainous areas, water is generally low.

In recent years, the use of phosphate in agriculture, industry and households has been increasing rapidly. This increase increases the concentration of phosphorus in rivers and lakes.

Environmental engineers generally want to know the total amount of phosphorus present in the waters. At the same time, the amount of organic phosphorus in wastewaters and sludges is of great importance for them.

In the past, phosphorus data were used to detect the formation of lime layer in the boilers of the plants or to prevent corrosion in water networks. Today, however, phosphorus measurements are performed to determine the biological reproductive potential of surface waters and to establish phosphorus limits in lakes, aquacultures, rivers and seas. Residual phosphorus determination is carried out as a regular process in the operation of wastewater treatment plants. Phosphorus is used as a nutrient in biological treatment and it is necessary to check whether it is sufficient in many water treatment plants.

Various methods are used for the determination of phosphate phosphorus by accredited laboratories.