An optical-fiber chemical sensor (optode) is described for the simultaneous determination of Zn2+ and Cd2+ mixtures using 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol immobilized onto XAD-4 (Br-PADAP/XAD-4). A simultaneous analysis was achieved by using a single-wavelength kinetic approach coupled with a regression model. Here, the Read More …
Month: October 2017
An optode for determination of mercury based on Nafion-diphenylcarbazone thin film in a flow-stream
An optode for determination Hg(II) ion has been developed using diphenylcarbazone (DC) immobilised in a Nafion(R) film. The film is transparent, homogeneous and mechanically strong, and changes in colour from orange to violet in the presence of Hg(II). The optode Read More …
A new solid state instrument for optical toxic metal ions sensing
A new measurement system for chemical optrodes based on the use of multi-LEDs and double-photodiodes is presented. A sensing area is illuminated through one branch of a bifurcated fibre optics with blue, yellow, red and IR LEDs of high intensities. Read More …
Polymeric encapsulated membrane for optrodes
Highly efficient and simple reagent immobilisation procedure for an optrode membrane has been developed. The preparation procedure combines two well-known physical immobilisation procedures, viz. adsorption and encapsulation techniques, applied sequentially which, in turn, produce a combined optical sensing layer. The Read More …
Capillary Optode: Determination of Mercury(II) in Aqueous Solution
A capillary optode for determination of mercury(II) in aqueous solution has been developed. The sensors are composed of the capillary glass tubes with a chemically sensitive coating on the inner surface, consisting of a 4-(2-thiazolylazo) resorcinol (TAR) and Nafion® composite Read More …
Characterisation of a Hg (II) ion optrode based on Nafion®-1-(2-thiazolylazo)-2-naphthol composite thin films
An optrode for Hg2+ ions based on a Nafion-1-(2-thiazolylazo)-2-naphtol (TAN) composite thin film has been developed. This optrode has a wide linear response range of 1-75 μM (pH 6) of Hg2+ ions with a limit of detection of 0.05 μM Read More …
Immobilised reagents for optical heavy metal ions sensing
Many ligands such as 1-nitroso-2-naphthol (NN), 4-(2-pyridylazo)resorcinol (PAR), 2,4-dinitrosoresorcinol (DNR) and 1-(2-pyridylazo)-2-naphthol (PAN) have been investigated in the development of optical sensors for heavy metal ions found in aquatic environments which include Co2+, Cu2+, Ni2+, Fe3+, Cd2+, Zn2+, Pb2+ and Read More …
A Simple Optical Flow Injection Ammonia Sensor
A simple optical flow injection ammonia sensor has been developed, based on the reflectance changes at 620 nm of an indicator fitted with a gas membrane. The sensor uses a commercially available pH indicator strip for a simple and fast Read More …
Simple on package indicator label for monitoring of grape ripening process using colorimetric pH sensor
A simple on package indicator label for grapes (Vitis vinifera L.) ripeness has been developed based on chlorophenol red (CPR). The CPR was immobilized onto the filter paper via absorption method to make the CPR membrane. The membrane as a Read More …
On-package dual sensors label for real-time monitoring of beef freshness
On-package dual sensors label has been constructed based on two pH indicators, and it has been applied to monitor the beef freshness. The two pH indicators used are methyl red (MR) and bromo cresol purple (BCP). The beef decay could Read More …