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Spectrophotometric catalytic determination of an ultratrace amount of iron(III) in water based on the oxidation of N,N-dimethyl-p-phenylenediamine by hydrogen peroxide

Journal Article · · Anal. Chem.; (United States)
DOI:https://doi.org/10.1021/ac00174a009· OSTI ID:6417289

A highly sensitive catalytic method for determining an ultratrace amount of iron(III) has been described. The method is based on the catalytic action of iron(III) on the oxidation of N,N-dimethyl-p-phenylenediamine by hydrogen peroxide in weakly acidic media. The catalyzed reaction was monitored spectrophotometrically at 514 nm by the fixed time method. The variables affecting the slope of the linear regression of the calibration curve were examined, and optimum conditions were established. At the fixed time of 5 min at 25/sup 0/C, molar absorptivity and Sandell's sensitivity were 1.7 x 10/sup 7/ L mol/sup -1/ cm/sup -1/ and 3.3 pg cm/sup -2/, respectively, and the sensitivity obtained from the linear regression was 0.04 ng mL/sup -1/. Most diverse ions did not interfere with the determination in the coexistence of a 1000-fold concentration of iron(III). The relative standard deviation of 0.8 ng mL/sup -1/ Fe was 2.4% (n = 6). The accuracy and the precision of the method were evaluated by the standard reference of pure metals. The method was successfully applied to the determination of trace iron in natural waters without preconcentration and separation.

Research Organization:
Nihon Univ., Fukushima (Japan)
OSTI ID:
6417289
Journal Information:
Anal. Chem.; (United States), Journal Name: Anal. Chem.; (United States) Vol. 60:23; ISSN ANCHA
Country of Publication:
United States
Language:
English