Bromide occurs in varying amounts in ground and surface waters of coastal areas from seawater intrusion and sea-spray precipitation. Under normal circumstances, the bromide content of most drinking waters is small, seldom exceeding 1 mg/L. Even levels of <100 μg/L can lead to formation of bromate or brominated by-products in disinfected waters. Industrial and oil-field brine discharges can contribute to the bromide in water sources.
Bromide ion-selective electrodes (ISE) are used to measure bromide in food products, beverages, plants, soils, and as an indicator in titrations. The following products include portable and benchtop ISE meters that can display bromide results in a choice of concentration units. Other products include calibration standard, ISA, and halide polishing strips for the halide solid state pellet.
Below are the most common products used for measuring bromide.
Benchtop pH/ISE meters
Benchtop pH/ISE meters include a two-channel option in which a pH probe can be connected to one channel and the bromide ISE to the other. The benchtop meters have the ion charge and formula weight pre-programmed for use with the bromide ISE. The benchtop meters also have incremental methods pre-programmed including the known addition, known subtraction, analyte addition, and analyte subtraction methods.
Portable pH/ISE Meters
Portable pH/ISE allow the flexibility to perform an ISE measurement with a portable meter even though the ISE measurement method is more suitable to a benchtop environment due to the addition of the ISA for fixing the ionic strength and the use of a magnetic stirrer to keep the sample homogenous. The portable pH/ISE meter has the ion charge and formula weight pre-programmed for concentration measurements.
The bromide ISE is a solid state electrode and is available as either a single half-cell or combination design that is complete with a reference cell. These electrodes incorporate a solid sensing surface made of compressed silver bromide.
Solutions for bromide measurement include an ISE standard and ISA for calibration and measurement. Other solutions include the fill solution that is used with the ISE.
Accessories include halide polishing strips and magnetic stirrers to ensure adequate mixing when using an ISE.