Cerium , hydrogen peroxide determination

Cerebral ischemia, lipid hydroperoxides, 612 Cerium(lll), hydrogen peroxide determination, 640... 

Returning to the explanation of induced reactions, we can say the following. Friend s proposal , according to which the error in the H2O2 determination is caused by reaction (83) catalyzed by manganese(II) or cerium(III) formed in the primary reaction between hydrogen peroxide and permanganate or cerium(IV) cannot be accepted. The reaction between the ions mentioned and peroxydisulphate at room temperature is very slow, and, furthermore, the increase in acidity —in contrast to its effect on the induced reaction —promotes the oxidation. There is... 

As compounds exhibiting enhancing effects on CL reactions, a variety of phenols, e.g., firefly luciferin and 6-hydroxybenzothiazole derivatives [12,13], 4-iodophe-nol [14], 4-(4-hydroxyphenyl)thiazole [15], 2-(4,-hydroxy-3 -methoxy-benzyli-dene)-4-cyclopentene-l,3-dione (KIH-201) [16], and 2-(4-hydroxyphenyl)-4,5-diphenylimidazole (HDI) and 2-(4-hydroxyphenyl)-4,5-di(2-pyridyl)imidazole (HPI)[17] (Fig. 6A), and phenylboronic acid derivatives, e.g., 4-phenylylboronic acid [18], 4-iodophenylboronic acid [19], and4-[4,5-di(2-pyridyl)-l //-imidazol-2-yl]phenylboronic acid (DPPA) [20] (Fig. 6B), in the luminol/hydrogen peroxide/peroxidase system are well known. Rhodamine B and quinine are used as sensitizers in the CL-emitting reaction between cerium (IV) and thiol compounds. This CL reaction was successfully applied to the sensitive determination of various thiol drugs [21-32],... 

An analytical application of cerimetry that is stiU in use is the determination of hydrogen peroxide by titration with a 0.1 M cerium(IV) sulfate solution to the pale blue end point of a ferroin indicator (Hurdis and Romeyn, 1954). The reaction is ... 

The fast reaction between cerium(IV) sulfate and hydrogen peroxide is useful to determine the concentration of hydrogen peroxide in solution by cerimetric titrations (see section 3). However, the decomposition of hydrogen peroxide by cerium(IV) in perchloric acid solution is slow at pH values above 0.7 (Baer and Stein, 1953 Ardon and Stein, 1956), at which colloid polymeric cerium(IV) complexes are formed. These are able to interact with hydrogen peroxide to afford colored complexes that are only slowly decomposed. At very low pH values, the polymeric complexes are not formed and decomposition of hydrogen peroxide is fast. 

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