Bromide assays are analytical techniques used to quantify the concentration of bromide ions in a solution. Bromide ions (Br⁻) are the anionic form of the element bromine and are commonly found in various environmental and biological samples, including water, soil, and biological fluids. Monitoring bromide levels is important for assessing water quality, evaluating the effectiveness of disinfection processes, and studying environmental contamination.
The most common method for bromide analysis is based on the reaction of bromide ions with a suitable oxidizing agent to produce bromine gas (Br₂), which is then quantified using colorimetric or titrimetric techniques. For example, in the alkaline-oxidation method, bromide ions react with chlorine or hypochlorite in the presence of a strong base (e.g., sodium hydroxide) to form bromine gas. The liberated bromine is then captured using an absorbent solution containing iodide ions, resulting in the formation of iodine (I₂), which can be titrated with a standardized solution of sodium thiosulfate (Na₂S₂O₃) to determine the amount of bromide present.