The standard curcumin method has been found to be suitable for the determination of borate in industrial effluents and sludges. Glaister et al. studied three sulphide ion selective electrodes in cascade flow and flow-through modes to investigate carrier stream, sample size and flow rate parameters in the analysis of sulphide in sewage effluents. The electrodes were successfully used as detectors of sulphide during flow injection analysis and the presence of ascorbic acid in the standard antioxidant buffer minimised deleterious effects of hydrogen peroxide in the samples. Hydrogen sulphide is brought to solution-vapour equilibrium in a closed flask under controlled conditions. The concentration of hydrogen sulphide vapour is determined by means of Draeger tubes, and related to the concentration in solution by means of a calibration graph.