DESIGN OF A SENSITIVE MEMBRANE OPTODE FOR IRON DETERMINATION

An optical chemical sensor has been developed for the sensitive determination of Fe (III) ions by spectrophotometry. The optical membrane was constructed by immobilization of methyltrioctylammonium chloride on triacetylcellulose polymer. The exchange of thiocyanate as counter ion in the membrane sensitized this film to Fe (III). The sensing membrane is capable of determining Fe(III) reversibly over a dynamic range of 7.11x10(-7)-8.88x10(-5)molL(-1) with a limit of detection of 6.02x10(-7)molL(-1) and a response time of 5min. This optode can easily be regenerated by 0.1molL(-1) of sodium fluoride solution. The relative standard deviation for eight replicate measurements of 7.11x10(-6) and 5.33x10(-5)molL(-1) of Fe (III) was 4.2 and 3.7%, respectively. The sensor was successfully applied for the determination of iron in tablet and water samples.