A sensor, based on multi-wall carbon nanotubes modified glassy carbon electrode (MWCNT/GCE), was developed for determination of fenitrothion. Determining the surface area of MWCNT/GCE showed that this surface is three times more active than that of a glassy carbon electrode. The experimental parameters, such as the amount of MWCNTs, pH of the fenitrothion solution, preconcentration potential an...

Perfluorinated carboxylic acids (PFCAs) represent an important group of persistent perfluorinated organic compounds commonly determined in environmental and biological samples. A reversed-phase HPLC method was developed based on derivatization of the PFCAs with the commercially available fluorescent reagent 3-bromoacetyl coumarin. The method was optimized and this resulted in the efficient sepa...

8-Hydroxyquinoline (8-HQ) was chosen as a powerful ligand for Hg solid phase extraction. Among several chelating resins based on 8-HQ, 5-phenylazo-8-hydroxyquinoline (5Ph8HQ) is used for mercury extraction in which the adsorption dynamics were fully studied. It has been shown that Hg(II) is totally absorbed by 5Ph8HQ within the first 30 minutes of contact time with t 1/2 5 minutes, following La...

A method based on the linear model of sorption dynamics (LMSD) is applied for the comparison of several solid phase extraction systems used for preconcentration of phenol from water solutions. The method includes the calculation of maximum concentration efficiency for the given values of preconcentration factor and recovery under scope of the model. Original parameters of LMSD were obtained fro...

The high mass transport caused by ultrasonic radiation in the preconcentration of trace metal species in anodic stripping voltammetry (ASV), leads to an order of magnitude enhancement in sensitivity. A Nafion-coated mercury thin-film working electrode is placed in a specially designed small-volume sonovoltammetric cell. The preparation and curing procedure for the Nafion film on a glassy carbon...

We have developed a new method for single-drop microextraction (SDME) for the preconcentration of organochlorine pesticides (OCP) from complex matrices. It is based on the use of a silicone ring at the tip of the syringe. A 5 μL drop of n-hexane is applied to an aqueous extract containing the OCP and found to be adequate to preconcentrate the OCPs prior to analysis by GC in combination with tan...

Amidino-thiourea immobilized glass beads (AGB I) were prepared and used as the microcolumn packing for the flow injection (FI) on-line separation and preconcentration of Ag(I) coupled with atomic absorption spectrometry (AAS) determination. Base metal ions and anions with a concentration of 2.0 mg mL(-1) had no interference with the determination of Ag(I). The limit of detection (LOD) of Ag(I) ...

An accurate, fast, and simple method for determination of thallium in environmental water samples with Zeeman electrothermal atomic absorption spectrometry (ZETAAS) by previous flotation preconcentration is given. The possibility of using cobalt(III) hexamethylenedithiocarbamate as a colloidal precipitate collector for simultaneous flotation separation of Tl(I) and Tl(III) from water matrices w...

A simple method has been developed for the preconcentration of mercury based on the adsorption of its Schiff’s base diphenylthiocarbazone (DPC)complex on a silica gel-immobilized Schiff’s base diphenylthiocarbazone (DPC)column. The influence of acidity, eluting agents, stability of the column, sample volume and interfering ions has been investigated in detail. The adsorbed complex could be elut...

The performance and optimization of an anion exchanger phase (SAX) in line with a hydrophobic phase (C18) was studied for the preconcentration of selenite [Se(iv)], selenate [Se(vi)], dimethylselenide (DMSe), dimethyldiselenide (DMDSe), diethylselenide (DESe) and diethyldiselenide (DEDSe), using a GC-MS system to characterize the different selenium species. Optimum separation and preconcentrati...