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A method for the determination of trace amounts of germanium by hydride generation atomic fluorescence spectrometry (HG-AFS) associated on-line with flow injection (FI) coprecipitation preconcentration was described. The samples, each spiked with Ni 2+ (500 μgml -1 ), were introduced into the FI system using time-based injection, and mixed with a NaOH solution (50 gl ...
In this paper, flame atomic absorption spectrometry was used for the determination of silver in various materials. The proposed preconcentration method is based on the continuous precipitation of silver as p-dimethylaminobenzilidene-rhodanine (PDBR) complex and dissolution of the precipitate with potassium cyanide. EDTA was added to the sample solution to mask large concentrations of Fe(III), Ni(II),...
A glucose biosensor with enzyme immobilised by sol-gel technology was constructed and evaluated. The glucose biosensor reported is based on encapsulated GOX within a sol-gel glass, prepared with 3-aminopropyltriethoxy silane, 2-(3,4-epoxycyclohexyl)-ethyltrimetoxy silane and HCl. A flow system incorporating the amperometric biosensor constructed was developed for the determination of glucose in the...
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...
A flow type microbial biosensor for direct measurement of trichloroethylene (TCE) was developed. The unique features of this novel microbial sensor were the use of the TCE degrading bacterium Pseudomonas aeruginosa JI104, the electrical detection of the chloride ion released by microbial degradation, and flow cell made of glass. Glass cell was used in order to suppress adsorption of TCE and made a...
An indirect amperometric method for the determination of sulfite in a flow injection configuration is described. The procedure is based on the amperometric measurement (E=0.1 V) of Cu(III) chemically generated by the S(IV) induced oxidation of Cu(II)/tetraglycine by dissolved oxygen. The dynamic analytical range was 5-100 μM with a detection limit of 1 μM. The repeatability for the determination (10...
The flow injection analysis of NADH was developed based on its inhibitory effect on a luminol-potassium hexacyanoferrate(III) chemiluminescence (CL) system. Under the optimum conditions, the decreased CL intensity was linear to the NADH concentration in the range of 5.0x10 -8 -2.0x10 -5 mol l -1 . The relative standard deviation was 1.24% for eight determinations...
A simple, fast and sensitive light-emitting diode (LED)-based photometric method for the differential determination of ppb-ppm levels of As(III) and As(V) in potable water in the presence of ppm levels of phosphate was developed. The detection chemistry is based on the well-known formation of arsenomolybdate, followed by reduction to heteropoly blue. The front-end of the measurement system is configured...
A flow injection (FI) method with on-line preconcentration using a mini-column loaded with 8-hydroxyquinoline immobilized on controlled pore glass (CPG-8HQ) is described for the determination of trace metals by ion chromatography (IC) with pyridine-2-6-dicarboxylic acid (PDCA) as the eluent. Copper, cadmium, lead, zinc, nickel and iron were determined at ppb level after post-column derivatization...
The flow injection analysis systems have been developed for the simultaneous determination of iron(III) and copper(II) and of iron(III) and palladium(II) based on the photochemical reactions of their thiocyanato-complexes. In the first system, a sample solution was injected in to nitric acid solution and mixed with ammonium thiocyanate solution, followed by spectrophotometric monitoring of the thiocyanato-complexes...
A simple gravitational field-flow fractionation (GrFFF) system was used for size separation of micron sized silica particles coated with hydrous iron oxide (geothite). The amount of iron on the particles was monitored either on-line by reverse-flow injection analysis (r-FIA) with chemiluminescence detection using luminol or off-line by electrothermal atomic absorption spectrophotometry (ETAAS). The...
The objective of this work is the development and optimization of a method for tartaric acid analysis in wines that does not require any sample pre-treatment and with adequate accuracy. A flow injection analysis manifold with three channels, using a dialysis unit to eliminate sample matrix interferences and to accomplish on-line dilution, is proposed for the spectrophotometrical determination of tartaric...
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