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Ion mobility increment spectrometry (IMIS) is a high sensitive selective ionization technology for detection and identification of ultra-trace constituents, including toxic compounds, CW-agents, drugs and explosives in ambient air or liquid sample. Like an ion mobility spectrometry (IMS), this technology rests on sampling air containing a mixture of trace constituents, its ionization, spatial separation...
A salicylate PVC-based membrane (SPME) and a coated graphite membrane (SCGE) electrodes by using a new tetracoordinate organonickel complex as ion carrier were prepared. Both sensors show a Nernstian response to salicylate ions over a very wide concentration ranges (1.0x10 -5 -1.0x10 -1 M for SPME and 1.0x10 -6 -1.0x10 -2 M for SCGE) in the pH of...
In this paper, continuous wavelet transform (CWT) is used to extract the number and the relevant positions of the α-helices and short peptides connecting α-helices and β-strands (connecting peptides) from the amino acid sequences of proteins. The amino acid sequence is first mapped into hydrophobicity sequence, and then transformed into CWT value of sequence domain in appropriate scale via CWT. The...
A total of seven pesticides and eight alkylphenols were monitored using this method for the determination of their trace levels in human cord blood. The pesticides are lindane, diazinon, α-endosulfan, β-endosulfan, endosulfan sulfate, chlorpyrifos and endrin; while the alkylphenols are 4-n-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol, 4-t-octylphenol, 4-n-heptylphenol, nonylphenol, 4-n-octylphenol...
An ''oil in water'' formulation was optimized to determine chromium in heavy crude oil (HCO) and bitumen-in-water emulsion (Orimulsion-400(R)) samples by transversally heated electrothermal atomic absorption spectrometry (TH-ET AAS) using Zeeman effect background correction. The optimum proportion of the oil-water mixture ratio was 7:3 v/v (70 ml of oil as the internal phase) with a non-ionic surfactant...
The performance of commercially available microtiter plate enzyme-linked immunosorbent assays (ELISA) kits specific for the determination of triazines (atrazine), chlorpyrifos, and diazinon was evaluated for sensitivity, intra-assay repeatability, and accuracy using samples of known concentration in aqueous solution. Mean percent recovery values were not significantly different among concentrations...
Uricase (UOx) and polyelectrolyte were used for preparation of a permselective multilayer film and enzyme multilayer films on a platinum (Pt) electrode, allowing the detection of uric acid amperometrically. The polyelectrolyte multilayer (PEM) film composed of poly(allylamine) (PAA) and poly(vinyl sulfate) (PVS) were prepared via layer-by-layer assembly on the electrode, functioning as H 2 ...
A simple method for the elements preconcentration on thin-layer paraffin-treated cellulose filters was proposed. It was found that pyrrolydinedithiocarbamates of As(III), Bi, Cd, Co, Cu, Fe(III), Ni, Pb, Se(IV), V(V) and Zn obtained after mixing of sample (3-5 ml min -1 ) and reagent (0.7-1.0 ml min -1 ) streams were quantitatively recovered from 100 ml sample. The sample...
In the present paper, a system for on-line preconcentration and determination of copper by flame atomic absorption spectrometry (FAAS) was developed. It was based on solid phase extraction of copper(II) ions on a minicolumn of Amberlite XAD-2 loaded with 2-(2-thiazolylazo)-5-dimethylaminophenol (TAM). The optimisation process was carried out using Doehlert designs. Four variables (sampling flow rate,...
A simple, rapid and sensitive method for the determination of two fluoquinolones (FQs), enoxacin (ENX) and ofloxacin (OFLX) is described by using flow injection analysis with potassium permanganate-sodium sulfite chemiluminescence detection. The calibration graphs for ENX and OFLX are linear in the range of 8.0x10 -10 -1.0x10 -5 and 1.0x10 -9 -1.0x10 ...
Electrochemistry and electrocatalysis of binuclear cobalt phthalocyaninehexasulfonate sodium salt (bi-CoPc) were investigated successfully in liquid crystal films of didodecyldimethylammonium bromide (DDAB) on pyrolytic graphite (PG) electrodes in aqueous solution. This new bi-CoPc-surfactant film modified electrode could reduce aggregation of bi-CoPc in aqueous solution, which was confirmed by the...
Four ionophores containing bipyridyl groups on a 7-deoxycholic amide derivative scaffold were designed and synthesized. Potentiometric evaluation of the Poly(vinyl chloride) (PVC) membranes containing those deoxycholic amides bearing bipyridyl moieties with a short linkage showed good affinity to silver(I) ion over alkali, alkaline earth and other transition metal cations. However, two bipyridyl groups...
Mercury(II)-chloride reacts with anhydrous methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone in a precise stoichiometry ratio (1:2), and weakly ionized compounds of mercury with ketones are formed and equivalent quantity of HCl is released. The application of a mercury anode for the quantitative generation of H + ions in 0.25 M sodium perchlorate in anhydrous methyl ethyl ketone,...
A single-wall carbon nanotubes (SWNT)-Nafion film coated glassy carbon electrode (GCE) was described for the determination of 4-aminophenol. In pH 3.0 sodium citrate-HCl buffer, the oxidation peak current of 4-aminophenol increases greatly at the SWNT-Nafion film coated GCE in contrast to that at both bare GCE and Nafion-film coated GCE. Moreover, the oxidation peak potential shifts to more negative...
A modified electrode consisting of copper dispersed in a poly-1-naphthylamine (p-1-NAP/Cu) film on a glassy carbon electrode was used as an amperometric detector for the on-line analysis of various carbohydrates separated by high performance liquid chromatography. The results obtained with this new sensor were compared to those obtained with a modified electrode based on the same polymer but with...
Based on the similarity in properties of arsenate and phosphate, the colorimetric method using the molybdene blue complex was tested in order to determine low As(V) concentration in waters. The influence of complex formation time, daylight, temperature and competitive anions (silicate and sulphate) upon complex formation was determined. Optimal complex formation was reached in 1 h at 20+/-1 o...
A new method for field speciation of Cr(VI) has been developed to meet present stringent regulatory standards and to overcome the limitations of existing methods. The method consists of passing a water sample through strong acid cation-exchange resin at the field site, where Cr(III) is retained while Cr(VI) passes into the effluent and is preserved for later determination. The method is simple, rapid,...
A procedure is described for the determination of nitrofurantoin and its toxic metabolite in urine from patients with urinary infection using supercritical fluid extraction (SFE) and liquid chromatography. The standard solution of toxic metabolite (radical anion) was obtained by electrochemical reduction of nitrofurantoin in an aprotic medium and chemical reoxidation with oxygen. In our initial SFE...
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