Episulfides were determined by a simple colorimetric assay using 4-(p-nitrobenzyl)-pyridine, which has been used previously for the detection and analysis of epoxides, organophosphates, and other alkylating agents. With episulfides, absorbance was directly proportional to concentration up to an absorbance of at least 1.0. No interference was observed with a variety of non-episulfide sulfur-cont...

The design, synthesis and physical evaluation of 1, a visible colorimetric 'naked eye' pyridyl based bis-amidothiourea sensor for anions, is described. This charge neutral sensor gives rise to significant changes in the absorption spectra upon interactions with several important biological anions such as AMP and ADP in 4:1 DMSO-H(2)O solution, while ATP was not detected. These colorimetric chan...

In order to find a fast, high efficient determination method of Organophosphorus Pesticides (OPPs) residue because OPPs widely used in crops pest control fields in China are causing fearful risks for environment as well as animals and human health, traditional and advanced determination methods were discussed in the study. Based on the spectrum analysis technology combined colorimetric OPPs res...

Biosensors are analytical devices that have found a variety of applications in medical diagnostics, food quality control, environmental monitoring and biodefense. In recent years, functional nucleic acids, such as aptamers and nucleic acid enzymes, have shown great potential in biosensor development due to their excellent ability in target recognition and catalysis. Deoxyribozymes (or DNAzymes)...

A new nonlinear dimensionality reduction method for multi-spectral images was presented to solve the problem brought by high dimensionality of multi-spectral images during color reproduction. Firstly, according to the characteristics of human visual system, the CIE standard observer color matching functions were weighted to the source spectral reflectance and then a principal component analysis...

Isoniazid is an important antibiotic, which is widely used to treat tuberculosis. This study presents a colorimetric method for the determination of Isoniazid based on localized surface plasmon resonance (LSPR) property of gold nanoparticles. An LSPR band is produced by reducing gold ions in solution using Isoniazid as the reducing agent. Influences of the following relevant variables were exam...

Two radiochemical (Irosorb 59 and Res-O-Mat Fc), a mechanized (DSA 560) and several manual colorimetric procedures (test combination of Roche, Merck and Haury) for the determination of the total iron binding capacity were compared with the transferrin-binding capacity (immunoprecipitation). Whereas all methods show a satisfactory correlation with the transferrin concentration, most colorimetric...

‘J’HE MOST COMMONLY USED METHODS for the estimation of uric acid are those colorimetric procedures utilizing the reduction of phosphotungstic acid (1-7). Since these procedures are not specific for uric acid, an enzymatic procedure utilizing uricase, which oxidizes uric acid to allantoin, has been employed by a number of investigators (8-12). The enzymatic method, dependent upon the absorption ...

The performance of a simple colorimetric assay for urinary nicotine metabolites to assess smoking status in diabetic subjects (n = 251) was investigated. Several variations of the colorimetric assay and a qualitative extraction procedure were evaluated in comparison with a cotinine immunoassay as the "gold standard." Among these, the best overall performance was achieved with the qualitative te...

We developed a colorimetric and chromatographic assay for oseltamivir to assess the authenticity of Tamiflu (F. Hoffmann-La Roche Ltd., Basel, Switzerland) because of a growing concern about counterfeit oseltamivir. The colorimetric assay is quantitative and relies on an extractable colored ion-pair complex of oseltamivir with Congo red or bromochlorophenol blue. The reverse-phase chromatograph...