Direct, Sensitive Determination of Trace Amounts of Dissolved Ferric Iron in Natural Water by Light Absorption Ratio Variation Spectrometry

Abstract

The chromophore eriochrome cyanine R (ECR) was used to sensitively coordinate Al(III) and Fe(III) in the presence of cetylpyridinium chloride (CPC) at pH 4.8. Trace amounts of Fe(III) can displace Al(III) from the Al(ECR)(CPC) ternary complex to form the Fe(ECR)(CPC) complex. The composition of the complexes was determined by the break point approach. The competitive displacement complexation was sensitive and highly selective, even if no masking reagent was added. An ongoing novel spectrophotometry, named the light-absorption ratio variation approach, was applied to the direct determination of Fe(III) in natural water with recovery between 92.5 and 106%. The detection limit was only 9 ng/mL Fe(III).

Spectrophotometric Study of Ternary Complex Forming Systems of Some Lanthanide Metal Ions with Eriochrome Cyanine R in Presence of Cetylpyridinium Bromide for Microdetermination

“…Lanthanum, holmium and manganese in synthetic ceramics, (La (0.8-x) Ho x Sr 0.2 MnO 3 ) by using chromogenic agent 5-Br-PADAP [2-(5-bromo-2-pyridylazo)-5-diethylaminophenol] and triton x-100 as a surfactant were determined by spectrophotometric method 12 . The chromophore eriochrome cyanine R (ECR) was developed to sensitively coordinate Al(III) and Fe(III) in presence of cetylpyridinium chloride (CPC) at pH 4.8.It is reported that trace amounts of Fe(III) can displace Al(III) from the Al(ECR)(CPC) ternary complex to form the Fe(ECR)(CPC) complex 13 .…”