A new chemiluminescence system for determination of cobalt.
The chemiluminescence of the reaction of tartaric acid with hydrogen peroxide in the presence of Co(II) in alkaline buffer media has been examined. The maximum emission wavelength is 460 nm. The kinetic curve of the chemiluminescence system has been modelled with a computer, and the reaction conditions have been optimized. Foreign ions, such as Fe(II), Cr(III) and Mn(II), interfere when present in more than 10-fold ratio to Co(II), but several ions can be tolerated when present in higher ratios to Co(II). The concentration range of linear response is from 3.5 x 10(-9) to 2.0 x 10(-6) g/ml, and the detection limit is 4 x 10(-11) g/ml. The procedure has been satisfactorily applied to determine trace cobalt in human blood serum.
Determination of nickel by 2‐thenoyltrifluoroacetone chemiluminescence
The chemiluminescence reaction involving 2‐thenoyltrifluoroacetone in alkaline H2O2—ClO∼ solution was studied. Ni2+ was found to be the most effective activator of the chemiluminescence, and hence, a novel chemiluminescence method for the determination of Ni2+ was developed. With reaction conditions optimized for Ni2 +, the detection limit for Ni2 + is 1.0 ng/ml, and the linear dynamic range is from 4n g/ml to 5 μg/ml. The intereference data for over 25 species are also provided. The procedure has been satisfactorily applied to determine nickel in river and waste waters.
Determination of humic acid by chemiluminescence
Abstract The analytical utility of the chemiluminescence resulting from the reaction of humic acid with permanganate is investigated. The chemiluminescence response curve rises sharply to a peak value at about 0.5 s after mixing and decays somewhat more slowly. The peak signal for a fixed humic acid concentration is shown to pass through a maximum near a permanganate concentration of 17 μmol l-1 and to increase continuously with potassium hydroxide concentration up to 2.0 mol l-1. Calibration plots of peak signal vs. humic acid concentration exhibit complex behaviour, being approximately linear up to about 20 mg l-1, curving slightly toward the concentration axis up to about 40 mg l-1, and then curving away from the concentration axis above 40 mg l-1. The detection limit for humic acid is about 0.7 mg l-1. No interference is observed for thirteen common inorganic species at typical levels in water samples. Substantial differences are observed for humic acid in selected samples determined by the chemiluminescence and visible absorption procedures.