EVALUATION OF A NUMBER OF METHODS FOR THE DETERMINATION OF TRACE AMOUNTS OF PHOSPHATES WITH FLOW-INJECTION ANALYSIS (FIA)

Four different FIA/spectrophotometric analytical systems, namely tin(I I) chloride (SnCl2), ascorbic acid, malachite green and rhodamine B me thods, were optimised and evaluated in order to find the lowest detect able limit for each for the determination of trace amounts of phosphat e on a routine basis. The SnCl2 analytical system gave the best overal l results. A low detection limit (2 mu g/l) combined with a relatively large linear working range (1 to 400 mu g/l) made this method superio r to the others. The relatively unstable nature of SnCl2 solutions tog ether with blockages that occurred due to high concentration ranges ar e, however, factors to be considered when employing the method routine laboratories.