Search results for "Chromogenic"
showing 9 items of 39 documents
Selective and Sensitive Chromogenic Detection of Cyanide and HCN in Solution and in Gas Phase
2013
Two triphenylmethane based chemodosimeters for selective and chromogenic sensing of cyanide anions in aqueous environments and of hydrogen cyanide in gas phase were prepared and studied.
Nerve agent simulant detection by using chromogenic triaryl methane cation probes
2012
Two triaryl methane cations have been used as probes for colorimetric detection of nerve agent simulants. Buffered mixed aqueous solutions of 1 and 2 showed bathochromic shifts in the presence of DCNP (diethylcyanophosphonate) and DCP (diethylchlorophosphate). The colour modulation can be observed to the naked eye. Appropriate mechanisms for the recognition event are proposed. © 2012 Elsevier Ltd.
Chromogenic Detection of Aqueous Formaldehyde Using Functionalized Silica Nanoparticles
2016
Silica nanoparticles functionalized with thiol reactive units and bulky polar polyamines were used for the selective colorimetric detection of formaldehyde. The reaction of thiols groups in the nanoparticles surface with a squaraine dye resulted in loss of the pi-conjugation of the chromophores, and the subsequent bleaching of the solution. However, when formaldehyde was present in the suspension, the thiol-squaraine reaction was inhibited and a chromogenic response was observed. A selective response to formaldehyde was observed only when the thiol and polyamine groups were anchored to the silica surface. The observed selective response was ascribed to the fact that bulky polyamines generat…
ChemInform Abstract: Synthesis of Tetrasubstituted 4,4′-Biimidazoles.
2012
Highly substituted 4,4′-biimidazoles were synthesized, in good to excellent yields, through a multicomponent imidazole ring synthesis by using imidazol-4-yl-ethane-1,2-diones as starting materials. The obtained compounds were preliminarily tested as chromogenic and fluorescent sensors for heavy metals.
Surfactant-assisted chromogenic sensing of cyanide in water
2009
Chromogenic cyanide recognition in water was achieved by the use of a hydrophobic dye in micellar containers.
Evaluation of CandiSelect4, a new chromogenic medium for isolation and presumptive identification of Candida species from clinical specimens
2008
Abstract In clinical laboratories, isolation of Candida species is generally based on the culture of specimens on Sabouraud dextrose agar. This strategy does not allow species identification on primary culture and makes it difficult to detect mixed cultures. Chromogenic media contain substrates that react specifically with different Candida species, and partly overcome these difficulties. Objectives The aim of this study was to compare two chromogenic media: (i) CandiSelect4 (C4), a new medium developed for direct identification of C. albicans and presumptive identification of C. krusei , C. tropicalis and C. glabrata (ii) CHROMagar Candida (CH), a medium licensed for direct identification …
A new simple chromo-fluorogenic probe for NO2 detection in air.
2015
[EN] A new chromo-fluorogenic probe, consisting of a biphenyl derivative containing both a silylbenzyl ether and a N,N-dimethylamino group, for NO2 detection in the gas phase has been developed. A clear colour change from colourless to yellow together with an emission quenching was observed when the probe reacted with NO2. A limit of detection to the naked eye of about 0.1 ppm was determined and the system was successfully applied to the detection of NO2 in realistic atmospheric conditions.
Magnifying chromoendoscopy for the detection of premalignant gastrointestinal lesions
2006
The prognosis for patients with malignancies of the gastrointestinal tract is strictly dependent on the early detection of premalignant and malignant lesions. At present, endoscopy can be performed with new, powerful high-resolution or magnifying endoscopes. Comparable to the rapid development in chip technology, the optic features of the newly designed endoscopes offer resolutions that allow new mucosal surface details to be seen. In conjunction with chromoendoscopy, the newly discovered tool of video endoscopy is much easier to use and more impressive than previously used fibreoptic endoscopy. This review summarises the value of magnifying endoscopy in the upper and lower gastrointestinal…
Chromogenic detection of nerve agent mimics
2008
The current rise in international concern over criminal terrorist attacks via chemical warfare (CW) agents has resulted in an increasing interest in the detection of these lethal chemicals. Among CW species, nerve agents are extremely dangerous and their high toxicity and ease of production underscore the need to detect these deadly chemicals via quick and reliable procedures. A number of detection systems have been developed, most of them based on enzymatic and physical methodologies. However, these usually show limitations such as low selectivity, lack of portability and a certain complexity in their use. An alternative to these classical methods that has been gaining interest in recent y…