FIA automatic dilution system for the determination of metallic cations in waters by atomic absorption and flame emission spectrometry.

A fully automated flow injection analysis (FIA) dilution system based on the zone sampling technique is described. The system relies on the use ofa PC-compatible microcomputerfor instrumental control and data acquisition and processing. The computer controls two rotatory valves which select different portions of the injected sample plug and then are re-sampled toward the detector. The system automatically chooses a suitable dilution factor for each sample. The dilution system was coupled to an atomic absorption spectrometer and to aflame photometer for the determination ofCa, Mg, Na, K, Cu, Zn and Fe in highly concentrated water samples. The methodology affords up to 10 O00-fold dilution factors with good precision (RSD < 3Uo) and high sampling rates (never lower than 90 determinations per hour).