Separation and detection of condensed phosphates in waste waters by ion chromatography coupled with flow injection

A method for the separation and detection of condensed phosphates in domestic waste waters using unsuppressed ion chromatography coupled with post-column flow injection detection of phosphorus is reported. The advantages of this technique over previously reported methods are its short analysis time (approximately 12 min per sample) and high sensitivity. The method was linear over the concentration range 10–1000 µg l–1 P for orthophosphate and 20–2000 µg l–1 P for pyrophosphate and triphosphate using a 500 µl sample loop. Detection limits for PO3–4, P2O4–7 and P3O5–10 were 10, 20 and 20 µg l–1 P, respectively. Recoveries of pyrophosphate and triphosphate for spiked filtered (0.22 µm) raw sewage samples were between 95 and 102% over the concentration range 50–1000 µg l–1.