BACKGROUND: SPECIATION OF IRON IN WATER SAMPLES IS VERY IMPORTANT FROM THE ENVIRONMENTAL POINT OF VIEW. THE OXIDATION STATE OF IRON CAN INDICATE ITS ELECTRICAL POTENTIAL AND MICROBIAL ACTIVITY [1]. THUS, METHOD DEVELOPMENT FOR DETERMINATION OF FE (II) AND FE (III) AS THE MOST IMPORTANT IRON SPECIES IN WATER SAMPLES HAS BEEN INTERESTED [2-4].METHODS: THE PH OF SAMPLE OR STANDARD SOLUTION CONTAINING FE (II) WAS ADJUSTED AT 4.5 USING ACETATE BUFFER. THEN 2, 4, 6-TRI (2' -PYRIDYL) L, 3, 5-TRIAZINE (TPTZ) AND SODIUM DODECYL SULFATE (SDS) WERE ADDED. SUBSEQUENTLY ETHANOL AS THE DISPERSER SOLVENT CONTAINING ionic liquid (HMIMPF6) AS THE EXTRACTION SOLVENT WAS RAPIDLY INJECTED INTO THE SOLUTION AND THE MIXTURE WAS ULTRASONICATED, TRANSFERRED INTO AN ICE-WATER BATH AND A CLOUDY SOLUTION WAS FORMED. AFTER CENTRIFUGING, THE UPPER AQUEOUS PHASE WAS REMOVED WITH A SYRINGE AND THE SEDIMENTED PHASE WAS DILUTED WITH ETHANOL AND ITS ABSORBANCE WAS MEASURED IN THE WAVELENGTH OF 589 NM AGAINST THE REAGENT BLANK. THE TOTAL FE WAS DETERMINED FROM THE REDUCTION OF FE (III) TO FE (II) WITH HYDROXYLAMINE. THE CONCENTRATION OF FE (III) WAS DETERMINED FROM THE DIFFERENCE BETWEEN THE CONCENTRATION OF TOTAL FE AND FE (II).RESULTS: TO ATTAIN A HIGH RECOVERY AND ENHANCEMENT FACTOR SOME IMPORTANT PARAMETERS SUCH AS THE TYPE AND VOLUME OF DISPERSIVE SOLVENT, AMOUNT OF ionic liquid, PH, TPTZ CONCENTRATION, ionic-STRENGTH, AND CENTRIFUGATION TIME WERE OPTIMIZED. UNDER THE OPTIMUM CONDITIONS, THE CALIBRATION GRAPH WAS LINEAR OVER THE RANGE OF 5.0-140.0 MG L-1 WITH THE LIMIT OF DETECTION OF 0.2 MG L-1. THE RELATIVE STANDARD DEVIATION FOR FIVE REPLICATE DETERMINATIONS OF FE (II) AT 100 MG L-1 CONCENTRATION LEVEL WAS FOUND TO BE 1.5%. THE ENHANCEMENT FACTOR DEFINED AS THE SLOPE RATIO OF CALIBRATION CURVE OF THE EXTRACTION METHOD TO THAT OBTAIN WITHOUT PRECONCENTRATION WAS 19.CONCLUSION: THE METHOD WAS SUCCESSFULLY APPLIED TO STEAM SAMPLES OF YAZD COMBINED CYCLE POWER PLANTS. THE PROPOSED METHOD WAS PROVED TO BE SIMPLE, SENSITIVE, FAST, AND ENVIRONMENTALLY FRIENDLY.