Application of Capillary Electrophoresis for Determination of Inorganic Analytes in Waters.

Aside from HPLC and GC, capillary electrophoresis (CE) is one of the most important techniques for high-performance separations in modern analytical chemistry. Its main advantages are the possibility of using different detection techniques, the possibility of in-capillary sample processing for preconcentration or derivatization, and ease of instrumental miniaturization down to the microfluidic scale. Those features are utilized in the separation of macromolecules in biochemistry and in genetic investigations, but they can be also used in determinations of inorganic ions in water analysis.

Fast and efficient deposition of broad range of analytes on substrates for surface enhanced Raman spectroscopy.

The majority of analytical chemistry methods requires presence of target molecules directly at a sensing surface. Diffusion of analyte from the bulk towards the sensing layer is random and might be extremely lengthy, especially in case of low concentration of molecules to be detected. Thus, even the most sensitive transducer and the most selective sensing layer are limited by the efficiency of deposition of molecules on sensing surfaces.

Comparison of three modifications of fused-silica capillaries and untreated capillaries for protein profiling of maize extracts by capillary electrophoresis.

In this work, capillary electrophoresis was applied to protein profiling of fractionated extracts of maize. A comparative study on the application of uncoated fused-silica capillaries and capillaries modified with hydroxypropylmethylcellulose, ω-iodoalkylammonium salt and a commercially available neutral capillary covalently coated with polyacrylamide is presented. The coating stability, background electrolyte composition, and separation efficiency were investigated.

Application of capillary electrophoretic chips in protein profiling of plant extracts for identification of genetic modifications of maize.

In this study, the chip gel electrophoresis with LIF detection was applied in protein profiling of fractionated and total extracts of maize standards. The sensitivity of such determinations can be enhanced by lyophilization of extracts or employing filtering and preconcentration with cutoff filters. Combinatorial peptide ligand library applied for sample processing prior to the electrophoretic analysis was, especially, an effective pretreatment step in the determination of low-abundance proteins.

Flow-injection preconcentration of chloramphenicol using molecularly imprinted polymer for HPLC determination in environmental samples.

The residue of antibiotic chloramphenicol (CAP) is important issue for food quality control and also for the environmental monitoring. It is banned for use in food-producing animals and has very limited use in human medicine, because of its severe impact on human health. Determination of trace level of CAP in environmental samples requires a very sensitive analytical method and efficient preconcentration procedure.

HPLC determination of perfluorinated carboxylic acids with fluorescence detection.

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 separation of PFCAs containing from 3 to 12 carbon atoms in molecule in 25 min run.

Enzymatic in-capillary derivatization for glucose determination by electrophoresis with spectrophotometric detection.

The following paper compares several procedures of in-capillary bienzymatic derivatization with regard to glucose determination with the use of glucose oxidase and horseradish peroxidase. The procedures discussed below include continuous contact in the capillary, plug-plug injection, and sequential injection with incubation in the capillary inlet. The reaction of hydrogen peroxide catalyzed by peroxidase was performed using two different substrates.

Net charge and electrophoretic mobility of lysozyme charge ladders in solutions of nonionic surfactant.

We report on the electrophoretic mobility and on the thermal diffusion of lysozyme proteins dissolved in aqueous solutions of a nonionic surfactant (C12E6) at a wide range of concentrations of the surfactant (0-20% by weight). We want to estimate the influence of a dense network of elongated micelles of C12E6 on the effective charge of the proteins as observed in the capillary electrophoresis experiments. The possible mechanism leading to the change in the effective charge of protein could involve the deformation of the cloud of counterions around the protein when it squeezes through the narrow (of the order of a protein diameter) aqueous channels formed in the solution of elongated micelles.

Determination of amino acids in saliva using capillary electrophoresis with fluorimetric detection.

In the present study a sensitive method for the quantification of main free amino acids in saliva using capillary electrophoresis with laser induced fluorescence detection was developed. As background electrolyte 20 mM borate buffer pH 9.5 was used.

Determination of amino acids in saliva using capillary electrophoresis with fluorimetric detection.

In the present study a sensitive method for the quantification of main free amino acids in saliva using capillary electrophoresis with laser induced fluorescence detection was developed. As background electrolyte 20 mM borate buffer pH 9.5 was used.

On-line preconcentration techniques in determination of melatonin and its precursors/metabolites using micellar electrokinetic chromatography.

Determination of melatonin (MT) (N-acetyl-5-methoxytryptamine) and related indole compounds using standard capillary electrophoresis (CE) system with UV detection was investigated. Satisfactory separations of six analytes i.e.

Determination of melatonin and its precursors and metabolites using capillary electrophoresis with UV and fluorometric detection.

A micellar electrokinetic chromatography method has been developed for simultaneous determination of melatonin and its precursors and metabolites. A 20 mM borate buffer pH 9.5 with 50 mM SDS served as the electrolyte.

Capillary electrophoresis speciation of chromium in leather tanning liquor.

We present a method for the speciation of chromium by capillary electrophoresis. Cr(III) was complexed with diethylenetriaminepentaacetic acid (DTPA) to form a negatively charged complex. Using 20 mM phosphate buffer of pH 8 containing 0.

Determination of dialysate creatinine by micellar electrokinetic chromatography.

Micellar electrokinetic chromatography with UV absorbance detection has been applied for fast and selective determination of creatinine in samples of postdialysate fluid. Optimization of the method was performed, with the best results being obtained using a 30 mM borate-100 mM sodium dodecyl sulphate background electrolyte, pH 9, with the detector set at 235 nm and an applied voltage of 17 kV across a fused-silica capillary of 67 cm/75 micro m I.D.

Flow-injection sample preconcentration for ion-pair chromatography of trace metals in waters.

Selected trace transition metal ions have been determined in an FIA/HPLC hyphenated system using on-line preconcentration on cellulose functionalised sorbent Cellex P. For HPLC separation ion-pair chromatography was employed with spectrophotometric detection at 510 nm using post-column derivatisation with PAR. Favourable kinetic conditions of sorption and elution as well as optimisation of hyphenated system allowed to obtain detection limits at sub-microgL(-1) level at 25 min preconcentration time.

Capillary electrophoretic determination of inorganic selenium species.

The performance of pyromellitic electrolyte for capillary zone electrophoresis of inorganic selenium species in the presence of selected common anions with indirect UV detection was investigated. The separation was achieved with pyromellitic electrolyte at pH 8.8 and hexamethonium hydroxide as the electroosmotic flow modifier.