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An on-line system with vapour generation (VG) and Fourier transform infrared (FTIR) spectrometric detection has been developed for the determination of free ammonium and organic nitrogen in agrochemical formulations containing hydrolyzed proteins. Commercial samples were digested, in batch mode, with sulphuric acid and the obtained solution was alkalinized on-line to transform the NH 4+ ...
Tyramine, histamine, putrescine and cadaverine, the most common biogenic amines indicating the food quality, were studied in the transglutaminase-catalyzed reaction. Transglutaminase (protein-glutamine gamma-glutamyltransferase EC 2.3.2.13) catalyzes an acyl transfer reaction between a donor substrate and an acceptor substrate (e.g. biogenic amine) and forms a cross-linkage between substrates with...
Two sets of ancient roman Egyptian blue (EB) samples and one set of EB samples synthesised in our lab, were analysed by EPR spectroscopy, a technique not commonly used in this field. The spectroscopic parameters obtained were used to attempt the discrimination of the provenance and of the manufacturing techniques of the investigated samples.The results obtained show that EPR technique could be very...
A microscale solid–liquid Pyrex extractor is described. The extractor has a novel detachable extraction vessel (H) containing a filter paper cylinder (C) over the reservoir. A filter paper cylinder (C) is firmly placed in the socket (E) with a plug (G) on which the cylinder has been placed. The sample is directly weighed in the extraction vessel (H) and the vessel is clamped (F) to the body (B). Contents...
A method for determination of toluene, ethylbenzene, p-xylene, o-xylene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene in water samples was developed by a fiber-in-tube liquid phase microextraction technique (fiber-in-tube LPME) coupled with GC-flame ionization detector (FID). The method used a tube packed with polytetrafluoroethylene (PTFE) fibers as an extraction medium, improving the stableness...
A micro flow injection wetting film liquid–liquid extraction system has been developed for trace analyte concentration and on-chip detection. A hydrophobic channel fabricated on a polycarbonate chip was used to support the wetting film, and hydrostatic pressure generated by the difference in liquid levels was employed to drive the fluids. Sequential injection of segments of aqueous sample solution...
Domperidone is a dopamine D 2 receptor antogonist, which has been used as antiemetic agent in human beings. It has been found in wastewater released by some pharmaceutical industries leading to the contamination of surface and ground water. Therefore, a sensitive, inexpensive and reproducible HPLC-SPE method was developed for the analysis of domperidone in the wastewater. The column used was...
Small amounts of polyvinyl alcohol (PVA; 0.5–1.5wt.%) added to extraction resin was synthesized by suspension polymerization. Their effects on the separation of rare earths (RE) were then investigated by conducting a relative comparison with the performance of pure extraction resin. The supporter and extractant of extraction resin were styrene–divinyl benzene copolymer and 2-ethylhexyl phosphonic...
The wet chemical etching of silicon by concentrated HF–HNO 3 mixtures in solar and semiconductor wafer fabrication requires the strict control of the etching conditions. Surface morphology and etch rates are mainly affected by the amount of dissolved silicon, that is continuously enriched in the etching solution with each etching run. A fast and robust method for the titrimetric determination...
A COD measurement by a photocatalytic oxidation method using nano-TiO 2 film was investigated. K 2 Cr 2 O 7 was added into the solution to enhance the efficiency of photocatalytic degradation, and simultaneously K 2 Cr 2 O 7 was reduced to Cr(III) by photogenerated electrons, which were adsorbed on the surface of TiO 2 . The measuring...
A procedure for the determination of cadmium, chromium, and lead in marine sediment slurries by electrothermal atomic absorption spectrometry is proposed. Slurry was prepared by mixing 10mg of ground sample with particle size smaller than 50μm completed to the weight of 1.0g with a 3% nitric acid and 10% hydrogen peroxide solution. The slurry was maintained homogeneous with an aquarium air pump. For...
The use of water-soluble calixarenes: p-sulfonato thiacalixarene (ST), tetra-sulfonatomethylated calix[4]resorcinarene (SR), calix[4]resorcinarene phosphonic acid (PhR) as chelating agents in cloud point extraction (CPE) of La(III), Gd(III) and Yb(III) ions using Triton X-100 as non-ionic surfactant is introduced. The data obtained indicate that both complexation ability and structure of calixarenes...
During the past decade, significant progress in the development of miniaturized microfluidic systems has occurred due to the numerous advantages of microchip analysis. This review focuses on recent advances and the key strategies in microchip capillary electrophoresis (CE) with electrochemical detection (ECD) for separating and detecting a variety of environmental pollutants. The subjects covered...
A quantitative analytical method for the determination of diclofenac in pharmaceutical preparations by diffuse reflectance in the visible region of the spectrum is presented. The color reaction is done directly in the measuring cell immediately after mixing, using small volumes of the analyte solution, of the reagent and of the buffer solutions. All reflectance measurements were carried out in a home...
A detection of alkaline phosphatase (ALP, EC 3.1.3.1) activity by the monitoring of pH changes caused by the biocatalytic action of the enzyme has been experimentally examined. Enzymatically catalyzed hydrolysis of monofluorophosphate has been found to be the best basis for such measurements. Protolytic equilibria connected with the developed biosensing system were recognized and the optimal conditions...
Redox behavior of three pesticides, namely isoproturon, carbendazim and methyl parathion was investigated electrochemically using hetropolyacid montmorillonite clay-modified glassy carbon electrode in the presence and absence of a surfactant, cetyl trimethyl ammonium bromide. A solution of 0.1M H 2 SO 4 in 50% aqueous alcohol (pH 1.0) was found to be suitable medium for electroanalysis...
A unique phenomenon, ion-enrichment and ion-depletion effect, exists in nanofluidic channels and is observed in amorphous silicon (α-Si) nanochannels as shallow as 50nm. As a voltage is applied across a nanochannel, ions are rapidly enriched at one end and depleted at the other end of the nanochannel. α-Si is deposited on glass by plasma enhanced chemical vapor deposition and is selectively etched...
The characteristics, performance, and application of an electrode, namely Pt|Hg|Hg 2 (DCF) 2 |graphite, where DCF stands for diclofenac ion, are described. This electrode responds to diclofenac with sensitivity of (58.1±0.8)mV/decade over the range 5.0×10 −5 to 1.0×10 −2 moll −1 at pH 6.5–9.0 and a detection limit of 3.2×10 −5 moll −1 . The electrode...
The report described a method of more stably dispersing oxidized carbon nanotubes (CNTs) by forming complex with polycation and the layer-by-layer self-assembly behavior of the complex with polyanion was studied. The properties of the self-assembled multilayer film containing carbon nanotubes were studied. Cyclic voltammetry, UV–vis–NIR spectroscopy, electrochemical impedance spectroscopy and scanning...
Uranium single particle analysis has been performed by inductively coupled plasma-mass spectrometry (ICP-MS) and the performances are compared with that provided by scanning electron microsopy and single particle counting. The transient signal induced by the flash of ions due to the ionisation of an uranium colloidal particle in the plasma torch can be detected and measured for selected uranium ion...
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