Diaminoazobenzene Research Articles

Polarographic Enzyme-Immunoassay for Trace Hepatitis B Surface Antigen

Abstract A polarographic enzyme-immunoassay for Hepatitis B Surface Antigen(HBsAg) has been established, in which horseradish peroxidase(HRP) is used as the labeled enzyme, o-phenylenediamine(OPD) as the substrate, and the enzyme-generated product,2,2′-diaminoazobenzene (DAA). is detected by linear-potential scan polarography. Under optimal conditions, the second derivative current of DAA is linear with the concentration of HBsAg from 0.1 to 5 ng/mL. The correlation coefficient(r) is 0.9994. The detection limit is 0.05ng/mL and the relative standard deviation is 6.7%(8 replicates). The sensitivity of the assay is about 20-fold higher than that of ELISA. The assay has been successfully applied for minute determination of HBsAg in both human serum and the negative control serum from ELISA kits.

In‐situ cure monitoring of diamine cured epoxy by fiberoptic fluorimetry using extrinsic reactive fluorophore

AbstractThis paper describes the application of a molecular sensor for in‐situ monitoring of epoxy‐diamine cure via remote sensing fiberoptic probes. A custom‐built, fiberoptic fluorimeter allows on‐line recording of fluorescence spectra directly from the cure environment. Cure reactions in epoxy‐diamine network, such as diglycidyl ether of bisphenol A‐diaminodiphenyl sulfone (DGEBA‐DDS) or diglycidyl ether of butanediol‐diaminodiphenyl sulfone (DGEB‐DDS), have been monitored by a reactive molecular sensor, diamino azobenzene (DAA). DAA exhibits sensitive changes in UV‐visible and fluorescence spectra due to the conversion of its primary amine groups to secondary and tertiary amine groups. Fluorescence intensities are correlated with extent of reaction in epoxy network and processing parameters, such as cure temperatures and time. The use of an internal reference dye for normalization of fluorescence intensities is necessary for the quantitative correlation of spectral signals with the network structure. Variables affecting the fluorescence intensity such as excitation volume, probe location, excitation intensity fluctuation, temperature, and background intensities from optical fiber can be calibrated by normalizing the signal intensities against the internal reference. Sulforhodamine 101 was found to be a satisfactory reference dye which provides stable, readable signals over temperatures up to 200°C.

Chemical behaviour of o,o′-diaminoazobenzene. Spectrophotometric determination of Pd(II)

Abstract A study of several physicochemical and analytical properties of o,o′-diaminoazobenzene (DAB) is reported and its chemical behaviour discussed from the point of view of Pearson's theory. DAB has been applied to the determination of palladium by means of a new extractocolorimetric method.

Preparation and properties of polyazo Schiff‐bases

AbstractFive colored polymeric Schiff‐bases were synthesized from 4,4′diaminoazo benzene and different dialdehydes and diketones. All the polymers were characterized by UV, IR, and NMR spectroscopy. Their physical properties and thermal characteristics are discussed.

OBSERVATIONS ON THE MODE OF ACTION OF SULFANILAMIDE

Domagk1reported in his original communication on the use of the hydrochloride of 4 sulfamido-2', 4' diamino azo-benzene in the treatment of experimental streptococcic infections of mice that phagocytosis of the streptococci by the leukocytes played an important role in clearing the tissues of streptococci in the treated mice. Levaditi and Vaisman2soon afterward advanced the hypothesis (without much experimental evidence) that this chemical interfered with capsule formation, thus rendering the streptococci susceptible to phagocytosis. The Trefouels and their associates3made the important observation in 1935 that para-aminobenzenesulfonamide was active as a therapeutic agent in curing mice of experimental streptococcic infections. Fourneau and his collaborators4first reported that para-aminobenzenesulfonamide had a bacteriostatic effect on the growth of certain molds. Colebrook and Kenny5stated that the hydrochloride of 4 sulfamido-2', 4' diamino azo-benzene and the disodium salt of 4 sulfamido-phenyl-2'-azo-7'-acetyl-amino-1'-hydroxynapthalene-3', 6'-disulfonic acid possessed practically no bacteriostatic