Water, of all the natural substances, comes closest to being the universal chemical solvent. This remarkable property makes it one of the most important components of all living organisms. Oxygen forms one of the abiotic factors governing the physiological and ecological operations of both plants and animals. It is the aerobic respiration that has been preferred by the living organisms as against anaerobic perhaps to oxidize the calorific compounds and mobilize energy. Thus oxygen becomes an indispensable factor for bodily metabolisms. Oxygen gets diffused in aquatic bodies from the atmosphere while the strength of oxygen in the system is enriched by the photosynthetic activities of phytoplanktons and regular hydrophytes. A minimum of 4 ppm [4 parts per million] of oxygen is required in the dissolved state to maintain and keep balance of the aquatic population. However, the amount of oxygen varies in water bodies according to its geographical location and usage. To know the normal fluctuation of oxygen in the water bodies, its quantitative estimation using Winkler's iodometric method at regular intervals is found to be significant.
This solution explains Winkler's iodometric method to analyze dissolved oxygen content in various samples of water.