Toxicity of hydrogen peroxide

Skin-Contact Toxicity Data for acute (short-term) exposures of the skin to corrosive and toxic liquids, solids, and gases are extremely limited, particularly where the consequences are severe or fatal injury and the available data may not be useful, from an engineering standpoint. For example, the skin toxicity of hydrogen peroxide to rats is stated as 4060 mg/kg, but the skin area and duration of exposure are not stated. Thus, it is not possible (with the available data) to estimate the relationship among percent of body surface exposed to a corrosive material, the concentration of the corrosive material, the duration of exposure (before removal of the corrosive material), and the severity of the effect. 

The use of hydrogen peroxide as an oxidant is not compatible with the operation of a biocatalytic fuel cell in vivo, because of low levels of peroxide available, and the toxicity associated with this reactive oxygen species. In addition peroxide reduction cannot be used in a membraneless system as it could well be oxidized at the anode. Nevertheless, some elegant approaches to biocatalytic fuel cell electrode configuration have been demonstrated using peroxidases as the biocatalyst and will be briefly reviewed here. 

It is important to note that the oxidation produces the superoxide free radical. Since it is toxic, the radical produced in reaction (a) must be removed. This is done in a reaction catalysed by superoxide dismutase, which produces hydrogen peroxide. However, this also must be removed (see Appendix 9.6 for discussion of free radicals). Removal of hydrogen peroxide is achieved in a reaction with reduced glutathione, catalysed by glutathionine peroxidase. 

Niacin can be detected by UV, ED, or FLD. UV is a widespread technique but it needs a longer preparation step and it does not reach high sensitivity. The FLD is more sensitive but it needs a pre or postcolumn derivatization to make niacin fluorescent. Krishnan et al. [599] describe a postcol-umn derivatization using cyanogens bromide and p-aminophenol, but this method involves toxic reagents. Mawatari et al. [600], instead, propose a fast, highly specific derivatization procedure, which involves UV irradiation at 300 nm in the presence of hydrogen peroxide and copper(II) ions. 

Bradley, M.O. Erickson, L.C. (1981) Comparison of the effects of hydrogen peroxide and X-ray irradiation on toxicity, mutation, and DNA damage/repair in mammalian cells (V-79). Biochim. biophys. Acta, 654, 135-141... 

With the addition of hydrogen peroxide to UV radiation, the elimination rate of pollutants can be increased. Hydrogen peroxide is cheaper than ozone production, and the application is less complicated and requires less safety precautions than the more toxic ozone. All this allows hydrogen peroxide/UV radiation to be easily included in a treatment scheme. It has its drawbacks though. 

This is supplied as the solid in sealed ampoules or as a solution in water or 2-methylpropan-2-ol (t-butyl alcohol). It must be handled in a fume cupboard. It is extremely irritating and toxic and constitutes a severe eye injury hazard. The solution in t-butyl alcohol (Expt 5.47) must be prepared and dispensed in an efficient fume cupboard, with the added protection of gloves and goggles. This solution is reasonably stable (e.g. the decomposition after one month is about 20%), provided that no 2-methylprop-l-ene arising from the t-butyl alcohol is present as an impurity. Formation of black coloidal osmium, which can catalyse the decomposition of hydrogen peroxide, for example in the hydroxylation of alkenes, is rapid. 

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