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A novel flow photometric detector based on paired emitter-detector diodes (PEDD), coupled with solenoid pulse micro-pumps is presented. The photometric detection chamber also plays a role of the reaction chamber. Both solutions, a sample and a reagent, are injected by solenoid micro-pumps directly and simultaneously into the chamber in countercurrent. This method ensures fast and effective mixing...
A formic acid (FA)-assisted sample preparation method was presented for protein identification via mass spectrometry (MS). Detailedly, an aqueous solution containing 2% FA and dithiothreitol was selected to perform protein denaturation, aspartic acid (D) sites cleavage and disulfide linkages reduction simultaneously at 108°C for 2h. Subsequently, FA wiped off via vacuum concentration. Finally, iodoacetamide...
An immunoassay in optimised conditions with a highly sensitive surface plasmon resonance (SPR) based biosensor was developed for the detection of the cancer biomarker carcinoembryonic antigen (CEA). Different formats of the immunoassay were initially investigated on the surface of the gold sensor chip. A self-assembled monolayer (SAM) was formed on the gold chip using 11-mercaptoundecanoic acid (MUDA),...
Tax-free diesel fuel is intended for off-road uses such as agricultural operations, but illicit use of this fuel does occur and is a convenient way of evading payment of excise taxes. Current enforcement to prevent this practice involves visual inspection for the red azo dye added to the fuel to indicate its tax-free status. This approach, while very effective, has shortcomings such as the invasive...
Controlling the composition of commercial beverages is critical for quality control. Rapid on-line measurements would allow optimization in real time. We have developed a methodology to monitor the volume fraction of ethanol and the carbohydrate concentrations in liquid mixtures using ultrasound frequency analysis. Characteristic distortion to ultrasound waves propagating through liquids is induced...
A novel chiral selector mono-6-deoxy-(2,4-dihydroxybenzimide)-β-CD (MDHB-β-CD) in which the derivatized group and the cavity of CD is linked by CH 2 –NC group, was successfully prepared, and the structural characteristics were determined by FT-IR, 1 H and 13 C NMR, MALDITOF-MS and element analysis. The corresponding stationary phase (CSP) was used in HPLC and the enantioseparation...
In this study, a label-free fluorescence detection method for DNA was designed using functional magnetic nanoparticles (MNPs) as affinity probes. With the advantage of magnetic feature, MNP-based affinity probes can be easily manipulated for trapping and sensing target species. Two types of MNP-based nanoprobes for trapping and detecting target DNAs were fabricated. The basic strategy for this approach...
A procedure to determine lead and zinc by anodic stripping voltammetry and copper by cathodic stripping voltammetry in natural river samples was developed and validated. Cu determination involves the adsorption of Cu complexes with 8-hydroxyquinoline (oxine) onto a hanging mercury drop electrode. All samples were studied at natural pH and following optimal conditions were found: an accumulation step...
This manuscript describes the development and validation of an ultra-fast, efficient, and high throughput analytical method based on ultra-high performance liquid chromatography (UHPLC) equipped with a photodiode array (PDA) detection system, for the simultaneous analysis of fifteen bioactive metabolites: gallic acid, protocatechuic acid, (−)-catechin, gentisic acid, (−)-epicatechin, syringic acid,...
Ion chromatographic (IC) methods have been compared in order to achieve an optimal separation of fluoride, acetate and formate under various elution conditions on two formerly introduced analytical columns (i and ii) and a novel one (iii): (i) an IonPac AS14 (250mm×4mm I.D.), (ii) Allsep A-2 (150mm×4.6mm I.D.), and (iii) an IC SI-50 4E (250mm (length)×4mm (internal diameter - I.D.)). The IC conditions...
The gas purge microsyringe extraction (GP-MSE) technique offers quantitative and simultaneous extraction, and rapid gas chromatographic–mass spectrometric determination of volatile and semivolatile chemicals is possible. To simplify the application, a new automatic temperature control system was developed here. Stable heating and cooling over a wide range of temperatures were achieved using a micro-heater...
In this work we tested two proteolytic enzymes (trypsin and pepsin) to evaluate metal bioaccessibility in marine sediments. Some working conditions were studied, in particular incubation time, enzyme concentration and solution/solid ratio, and metals release mechanisms were investigated using both untreated and denatured enzymes.The results obtained with trypsin and pepsin were compared with each...
Molecularly imprinted monolithic fibers were synthesized and evaluated for solid-phase microextraction (SPME) of acetaldehyde from head-space of beverages stored in poly(ethylene terephthalate) (PET) bottles. The fibers were prepared by co-polymerization of methacrylic acid and ethylene glycole diethacrylate as functional monomer and cross-linker, respectively. Acetaldehyde was used as template molecule...
An ultrasonic assisted solid–liquid extraction method was developed to determine the level of lead in the brain and urine of rats. Lead was determined by electrothermal atomic absorption spectrometry with longitudinal-Zeeman background correction. Several analytical drawbacks were addressed and overcome, namely small brain sample mass and the formation of precipitate in the urine samples. Utrasonication...
Methods applied in acrylamide quantification in foods have been reviewed in this paper. Novel analytical techniques like capillary electrophoresis (CE), immunoenzymatic test (ELISA) and electrochemical biosensors, which can replace traditional methods like high performance liquid chromatography (HPLC) and gas chromatography (GC) were presented. Short time of analysis and high resolution power of electrophoretic...
Residues of perfluorinated phosphonic acids (PFPAs) and perfluorooctane sulfonic acid (PFOS) were investigated in various Dutch surface waters, sludge and sediments. For this purpose, a liquid chromatographic (LC) method was optimized by testing several columns with different mobile phases. Atmospheric pressure chemical ionization (APCI) was chosen for the LC tandem mass spectrometry (MS/MS) analysis...
Wine age prediction based on its intrinsic characteristics can provide significant assistance to oenologists’ quality evaluations, concerning wine ageing process control and wine quality assurance. Simpler, faster, cheaper and affordable analytical procedures would be greatly welcome to establish such a practice. In this study, we present a new and reliable strategy to predict wine age, in the long...
A novel electrochemical sensor based on poly(2-hydroxy-5-[(4-sulfophenyl)azo]benzoic acid) film modified glassy carbon electrode for fast and simple quantification of trace amount of quetiapine fumarate (QF) was developed. It exhibits excellent enhancement effects on the electrooxidation of QF facilitating preconcentration of drug molecules on the electrode surface. Based on its strong adsorptive...
A highly selective and sensitive PVC membrane, containing phenylurea substituted calix[4]arene was found to be a suitable ionophore for monohydrogen phosphate (HPO 42− ) ions that exhibited a Nernstian response (with a slope of −29.4±0.3mVdecade −1 ). The working concentration range of the electrode was 6.0×10 −8 –1.0×10 −1 molL −1 with a detection limit...
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