Tetramethylbenzidine, oxidation

Domenech, A., Garcia, H., Casades, L, and Espla, M. 2004e. Electrochemistry of 6-nitro-1, 3, 3 -trimclhylspiro 2//-l-benz.opyran-2,2 -indolinc associated to zeolite Y and MCM-41 aluminosilicate. Site-selective electrocatalytic effect on lV,lVJV, 7V -tetramethylbenzidine oxidation. Journal of Physical Chemistry B 108, 20064—20075. 

The determination of organic compounds by their direct catalytic effect on indicator reaction rates is a relatively unexplored ai ea promising valuable analytical chai acteristics, as we have recently shown in the determination of traces of unsymmetrical dimethylhydrazine (UDMH) by the oxidation of 3,3, 5,5 -tetramethylbenzidine (TMB) by atmospheric oxygen initiated with persulfate [1]. 

Dvorak V, Nemek I, Zyka J (1967) Electrochemical oxidation of some aromatic amines in acetonitrile medium II. benzidine, N,N,N ,N -tetramethylbenzidine, and 1,4-phenylene-diamine derivatives. Microchem J 12 324-349... 

When I- is titrated with Cu(Cl04)2 in AN, it is oxidized in two steps, I ->If and If ->I2. The formal potentials of the two steps are +0.396V and -0.248V vs Ag/Ag+, respectively. Many organic compounds, such as hydroquinone, ascorbic acid, ferrocene and its derivatives, allylamine, hydroxylamine, phenylhydrazine, thiourea and SH compounds, can also be titrated with Cu(II) in AN. Figure 4.9 shows the titration curves of tetramethylbenzidine (TMB) in AN [12]. In dry AN, TMB is oxidized in two steps as follows ... 

The peroxidase-catalyzed oxidation of 2,2 -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), o-phenylene-diamine (PDA), and 3,3, 5,5 -tetramethylbenzidine (TMB) was found to be activated by tetrazole 2 and 5-aminote-trazole and weakly inhibited by 1,5-diaminotetrazole 33 <2004MI283>. Bhattacharya and Vemula studied the effect of heteroatom insertion in the side chain of 5-alkyl-177-tetrazoles on their properties as catalysts for ester hydrolysis at neutral pH <2005JOC9677>. l-(2-Iodophenyl)-177-tetrazole was successfully used in Heck reactions to give the cross-coupled products in excellent yield <2004TL4113>. 

Anodic oxidation has been used for generating radical-cations from amines such as i 7, .Af,iV,i f -tetramethylbenzidine (Fritsch and Adams, 1965) and triethylenediamine (McKiimey and Geske, 1965), and from aromatic ethers such as jj-dimethoxybenzene (Zweig et al., 1964). 

Amine radical-cations have been generated by the treatment of para-substituted anilines with ceric ion (Stone and Waters, 1962 Fox and Waters, 1964). When the para position is free, the initial radical-cation can react further for example, the oxidation of triphenylamine with lead tetra-acetate in the presence of boron trifluoride (Allara ei al., 1965) or with iodine (Stamires and Turkevich, 1963) gives the radical cation Ph3N+ , and, when excess of triphenylamine is used, the former oxidant leads to the radical-cation of A(, .A/, W, A -tetraphenylbenzidine. The only radical observed by the oxidation of dimethylanihne either electrochemically (Mzoguchi and Adams, 1962) or with lead tetraacetate and boron trifluoride (Allara et al., 1965) is the radical-cation of iV, .A, .A7, iV -tetramethylbenzidine. The relatively stable (hindered) anilino radical (40) has been generated from the corresponding aniline by flash photolysis audits e.s.r. spectrum has been measured in n-hexane (Land and Porter, 1961). The electronic spectrum of this radical is very similar to that of the unsubstituted anilino radical, detected during flash photolysis of aniline, but this radical is so short-lived that it has not yet been detected by e.s.r. 

Using a new method, the catalytic kinetic method of analysis, Beklemishev et al. (1997) measured the concentrations of manganese in tap and river water. Their analytical method relies on an indicator reaction that is catalyzed by Mn(Il) (the oxidation of 3,3, 5,5 -tetramethylbenzidine [TMB] by potassium periodate [KIO4]) and is carried out on the surface of a paper-based sorbent. The advantages of this new technique are that it has a much lower detection limit (0.005 pg/L) than do established methods and is transportable, allowing it to be used for rapid tests in the field (i.e., spot tests and similar procedures). 

Water Preconcentrate manganese-containing solution and 3,3, 5,5 -tetramethylbenzidine (TMB) onto filter paper add oxidant KIO4 to catalyze oxidation measure absorbance Catalytic kinetic method of analysis 0.005 pg/L No data Beklemishev et al. 1997... 

HRP oxidizes 3,3, 5,5 -tetramethylbenzidine (TMB) in the presence of hydrogen peroxide to give a product with deep blue color. The enzymes differ significantly in their size and isoelectric point (lEP), with HRP being smaller (44 kDa) and having a higher lEP (7.2) compared to ALP... 

Traces of phosphate ions can be determined by the reaction between molybdate, phosphate, and 3,3, 5,5 -tetramethylbenzidine in an acidic medium to form a color charge transfer complex ion (458 nm). Another new approach for ortho- hos-phate determination is based on the reaction of phosphate with the by-products of the oxidation reaction between diphenylamine and molybdenum(VI) in a formic acid solution medium (340 nm). 

We observe only the V component of the oxidation products of DMA. We do not observe any changes in the IR spectrum of DMA-treated diatomite after washing the sample with benzene. It is noted that the V and Y components of the oxidation products of DMA are not desorbed during the washing with benzene but the excess DMA and tetramethylbenzidine (TB) are washed out with benzene, IR spectroscopic analysis shows that sepiolite and loughlinite absorb DMA and then react with it more easily than diatomite. The adsorption capacity sequence of DMA for the minerals studied is found to be sepiolite>loughlinite>diatomite. 

The influence of some ternary amines exhibiting strong electton donor properties on the electrochemistry of C60 and C70 was studied by Rao et al. [42]. Only a slight influence of tetramethyl-p-phenylenedia-mine (TMPD) and M,AlyAl JV -tetramethylbenzidine on the electrochemistry of the fullerenes was found. However, the oxidation peak of TMPD was split in the presence of fullerenes suggesting some interactions between the fullerenes and TMPD. Addition of tetrakis-2,3,5,6-(A,A-dimethylamino)benzene (TDAB) to a CH2CI2 solution of C60 shifted in a positive direction... 

Zhou and coworkers demonstrate that a highly stable, mesoporous PCN-222(Fe) meets the prerequisites for biomimetic catalytic application (Scheme 4). PCN-222(Fe) shows good peroxidase-mimic catalytic activity in the oxidation of pyrogallol, 3,3,5,5-tetramethylbenzidine, and o-phenylenediamine. The excellent catalytic performance of PCN-222(Fe) is attributed to the stable 3D structure with large open channels of 3.7 nm in diameter to increase the diffusion rate of substrates. 

Amines. Radical cations have been obtained by electrochemical oxidation of monoamino derivatives in the case of 9-amino-10-phenylanthracene [144, 145] of diamino derivatives in the case of p-phenylenediamine [66, 146, 147], l,4-diamino-2,3,5,6-tetramethyl-benzene [129], tetramethylbenzidine [148, 149], and triethyldiamine [150] of tetraamino derivatives in the case of tetrakis(dimethyl-amino) ethylene [151]. 

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