| Abstract: | A double-tube separation system with an inner tube of microporous poly(tetrafluoroethylene) (PTFE) and an outer tube of PTFE, is proposed for the continuous determination of TTHMs (total trihalomethanes) in drinking water. The TTHMs in the sample after mixing sodium sulfite solution, are separated with the double-tube system at 50°C and are mixed with alkaline nicotinamide solution, and then heated to 98°C. After cooling in an ice bath, the reaction product is fed to a fluorometer and the fluorescence intensity excited at 372 nm is measured at 467 nm. There was no interference from unknown species existing in drinking water and river water by using the membrane separation system. A response was obtained within 8 min. The detection limit (S/N = 3) was 0.8 μg/1. The present method was applied to the determination of the TTHMs in drinking water. |
