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A screen-printed biosensor for the detection of pesticides in water miscible organic solvents is described based on the use of p-aminophenyl acetate as acetylcholinesterase substrate. The oxidation of p-aminophenol, product of the enzymatic reaction was monitored at 100 mV vs. Ag/AgCl screen-printed reference electrode. Miscible organic solvents as ethanol and acetonitrile were tested. The acetylcholinesterase...
An interesting inhibitory effect of rutin on the chemiluminescence (CL) reaction between luminol and periodate was reported, and this effect was used for the determination of rutin in medicine and human urine. The CL reagents, luminol and periodate, were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and periodate, which were eluted from the column...
In the present paper, a study on the characterisation of beer samples according to their mineral content has been carried out. Zn, P, B, Mn, Fe, Mg, Al, Sr, Ca, Ba, Na and K were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) in 32 beer samples. Lager, dark and low alcoholic content beers were considered. The analysed elements were considered as chemical descriptors...
A new, sensitive and robust time-based flow injection (FI) method for on-line preconcentration and determination of ultra trace amounts of chromium(VI) by flame atomic absorption spectrometry (FAAS) has been elaborated. The sample is initially mixed on-line with ammonium pyrrolidine dithiocarbamate (APDC) and the Cr(VI)-PDC chelate is absorbed quantitatively on a mini-column packed with polytetrafluoroethylene...
A selective flow injection electrogenerated chemiluminescence(CL) method for the determination of vanadium is described in this paper. It was based on the chemiluminescence reaction of luminol with vanadium(II), which was on-line electrogenerated from vanadate using a flow-through carbon electrolytic cell. Under the optimal conditions, the CL intensity was linear to the concentration of vanadium in...
A new first-derivative photochemically induced fluorescence (D-PF) method is proposed for the determination of sulphamethoxazole (SMXZ) in milk. A 50:50 (v/v) methanol: water medium, UV irradiation time of 2 min, and pH 5.70 were fixed. Standard addition method was used with the derivative spectra of the increase spectra as analytical signal. For determination in drugs, direct increase of fluorescence...
A novel analysis of explosives via the coupling of an airline passenger personnel portal with a high-flow (HF), high-resolution (HR) ion mobility spectrometry (IMS) was shown for the first time. The HF-HR-IMS utilized a novel ion aperture grid design with a 63 Ni ionization source while operating at ambient pressure in the positive ion mode at 200 o C. The HF-HR-IMS response characteristics...
The first long pathlength fiber optic-based sensor system to measure pCO 2 in natural waters and the atmosphere is described. The sensor is based on a liquid-core (an indicator-HCO 3- /CO 32- buffer solution) waveguide made of a low refractive index amorphous fluoropolymer tubing, the wall of which serves as a gas-permeable membrane to sense pCO 2 changes...
Dibenzo-18-crown-6 (DB18C6) is used for the liquid-liquid extraction, and recovery of titanium from paints, pigment, paper and pulp industries. The extraction mechanism of titanium(IV) from pH 4 medium with DB18C6 in dichloromethane was investigated. The DB18C6 concentration in organic phase, the concentration of titanium, the effect of pH and interference ions such as Mo 6+ , V 5...
An enzymatic reactor was constructed by the immobilization of polyphenol oxidase (PPO) from avocado (Persea americana) crude extract in an inorganic support of controlled pore silica (CPS), after a previous step of silanization. This inorganic support has been used as an excellent carrier to immobilize this enzyme and the enzymatic reactor was used in a flow injection system for the determination...
An analytical method for the determination of glutamic acid by the sequential perturbation caused by different amounts of glutamic acid on the oscillating chemical system involving the Cu(II)-catalyzed oscillating reaction between hydrogen peroxide and sodium thiocyanate in an alkaline medium is proposed. The method relies on the linear relationship between the changes in the oscillation amplitude...
A simple and low cost flow injection (FI) system with bead injection (BI) was developed for determination of low concentration (μmol l -1 ) of iron in water samples. Chelex-100 chelating resin beads, trapped in a jet ring cell, were employed. The intensity of red complex of 1,10-phenanthroline with Fe 2+ was monitored using colorimetric detector with a LED green light source...
Chromium(III) is commonly found in large quantities in tannery wastewaters. For this reason, the recovery of the chromium content of these wastewaters is necessary for environmental protection and economic reasons. Removal and recovery of chromium were carried out by using ion exchange resins. To this purpose, two weakly acidic exchange resins Amberlite IRC 76 and Amberlite IRC 718 and a strongly...
Analysis of organotin compounds in vegetal samples is not well documented, and no specific extraction procedure of those species from vegetal matrix can be found in the literature. In order to develop such a procedure, we have compared in a first step the performances of six extracting solutions based on HCl, CH 3 COOH, NaOH, TMAH, enzymatic mixture and ethyl ethanoate. HCl-based extraction...
Since the appearance, in the early eighties, of first publications describing plasma source mass spectrometry as a viable analytical technique, there has been a rapid increase in the number of papers detailing its possible applications, instrumental developments and fundamental studies. In the laboratories involved in the environmental or food monitoring problematics, inductively coupled plasma-mass...
A new tripodal compound, 1,1,1-tris(N-ethyl-N-phenylamino-carboxylmethoxymethyl) propane, has been synthesized and evaluated as an ionophore in PVC membrane electrode for the analysis of alkali and alkaline earth metal cations. The influence of the nature of the plasticizers (o-NPOE, DBP and DOP) and of the amount of incorporated ionophore on the characteristics of the electrode was discussed. Selectivity...
A novel approach was developed for the separation and detection of a benzo[a]pyrene B[a]P-DNA metabolite (tetrol I-1) in the presence of DNA using CE and laser induced fluorescence. Tetrol I-1 in the presence of DNA is intercalated and undergoes fluorescence quenching. Thus, an equilibrium is established between the intercalated tetrol I-1 and the uncomplexed tetrol I-1. It is only the uncomplexed...
A novel polyacrylaminoimidazole chelating fiber is synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber) and used for the preconcentration and separation of trace Au(III), Hg(II) and Pd(IV) ions from solution samples. The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 15.0 mlmin -1 at pH 3 and can also be desorbed with...
The water-soluble polymers poly(ethylenimine), quaternized poly(ethylenimine), and poly-4-vinyl-(N-benzyltrimethyl) ammonium chloride were found to be able to change the kinetics of the reaction of cobalt with nitroso-R-salt and the optical density of the cobalt complex formed. The optimum pH range for the complex formation was a wide range from 1 to 10 and at pH 2 the reaction developed instantly...
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