Determination of sulfate in seawater and natural brines by 133Ba and membrane dialysis
Dissolved sulfate is determined by precipitation with the radioisotope 133 Ba and counting of the precipitate on a scintillation counter. Precipitation is carried out in dialysis bags; excess 133 Ba is removed via diffusion by soaking the bags in distilled water for 12 h, and the bags are then placed directly in the well of the scintillation counter. The procedure eliminates previous errors caused by washing and transferring of the precipitate and permits analysis of 0.5–3,000 µ g·ml −1 sulfate in a 1.0-ml sample. The detection limit is increased by simply increasing the sample volume up to 5.0 ml. The technique is interference-free in natural waters ranging from freshwater to brines of 1.5 times the salinity of seawater.
Limnology and Oceanography↗