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 free chlorine in water by chemiluminescence reaction with hydrogen peroxide
The analytical utility of the hydrogen peroxide—hypochlorite singlet oxygen chemiluminescence reaction for the determination of hypochlorite in water is investigated. Effects of pH and hydrogen peroxide concentration are discussed and interference data for over 35 species in the absence and presence of hypochlorite are provided. The limit of detection is 4 μg l-1 with a usable non-linear calibration curve up to about 200 μg l-1. The new method is shown to be relatively free from interferences and to give results for tap water comparable to a standard colorimetric method based on a reaction with N, N-diethyl-p-phenylenediamine.