Development of a new phosphorescence sensor based on surface molecularly imprinted Mn-doped ZnS quantum dots for detection of melamine in milk products.

This paper presents a novel room temperature phosphorescence sensor (IMIPs-ZnS QDs RTP sensor) based on inorganic surface molecularly imprinted polymers and Mn-doped ZnS quantum dots (QDs) for the rapid detection of trace melamine (MEL) in commercial milk products. The surface of Mn-ZnS QDs was modified with 3-(mercaptopropyl) trimethoxy silane (MPTS). Then, MEL, 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) were used as a template/target molecule, functional monomer, and cross-linker, respectively.

Smartphone digital image colorimetry combined with dispersive solid-phase microextraction for the determination of boron in food samples.

Simple, inexpensive and accurate analytical methods are in high demand. Dispersive solid-phase microextraction (DSPME) was used in combination with smartphone digital image colorimetry (SDIC) to determine boron in nuts as an approach replacing existing costly alternatives. A colorimetric box was designed to capture images of standards and sample solutions.

Switchable-hydrophilicity solvent liquid-liquid microextraction combined with smartphone digital image colorimetry for the determination of palladium in catalytic converters.

Switchable-hydrophilicity solvent liquid-liquid microextraction was coupled with smartphone digital image colorimetry for the determination of palladium as its metal chelate with N,N-diethyl-N'-benzoylthiourea. Images of the colored extract were captured in a homemade colorimetric box, which were split into their red-green-blue channels. The blue channel was used to determine the concentration of palladium.

Smartphone digital image colorimetry combined with solidification of floating organic drop-dispersive liquid-liquid microextraction for the determination of iodate in table salt.

Smartphone digital image colorimetry (SDIC), combined with solidification of floating organic drop-dispersive liquid-liquid microextraction (SFOD-DLLME), was proposed for the determination of iodate ions. A colorimetric box was designed to capture images of sample solutions. Factors affecting the efficiency of SDIC included type of phone, region of interest, position of camera, and distance between camera and sample solution.

Multiplex enumeration of Escherichia coli and Salmonella enteritidis in a passive capillary microfluidic chip.

Multiplex detection and quantification of bacteria in water by using portable devices are particularly essential in low and middle-income countries where access to clean drinking water is limited. Addressing this crucial problem, we report a highly sensitive immunoassay sensor system utilizing the fluorescence technique with magnetic nanoparticles (MNPs) to separate target bacteria and two different types of quantum dots (CdTe and Ni doped CdTe QDs) incorporated into a passive microfluidic chip to transport and to form sandwich complexes for the detection of two target bacteria, namely Escherichia coli (E. coli) and Salmonella enteritidis (S.

Fast fluorometric enumeration of E. coli using passive chip.

In this report, a passive microfluidic chip design was developed for fast and sensitive fluorometric determination of Escherichia coli (E. coli) based on sandwich immunoassay. Initially, magnetic nanoparticles (MNPs) and chitosan modified mercaptopropionic acid capped cadmium telluride (CdTe) quantum dots (QDs) were functionalized with E.

Use of Water Soluble and Phosphorescent MPA-capped CdTe Quantum Dots for the Detection of Urea.

Objectives: To describe a method for the determination of urea in blood serum using urease enzyme and 3-MPA-capped CdTe quantum dots.

Materials And Methods: The method is based on the increase in pH of the solution as a result of the reaction between urea and urease, which causes an increase in the phosphorescence signal of MPA-CdTe quantum dots in the pH range of 2.5-5.

Polyethyleneimine brushes effectively inhibit encrustation on polyurethane ureteral stents both in dynamic bioreactor and in vivo.

Polyurethane (PU) ureteral stents have been widely used as biomedical devices to aid the flow of the urine. Due to the biofilm formation and encrustation complications it has been hindered their long term clinical usage. To overcome these complications, in this study, cationic polyethyleneimine (PEI) brushes grafted on PU stents and their performances were tested both in a dynamic biofilm reactor system (in vitro) and in a rat model (in vivo).

Effects of heat treatment parameters on liquid whole egg proteins.

The aim of this study was to analyse the effect of heat treatment parameters on liquid whole egg (LWE) proteins by using ultraviolet-visible (UV-VIS) spectroscopy and capillary electrophoresis (CE). Heat treatment (at 60-68°C for 1-5min) was applied to LWE. Treated LWE was centrifuged and supernatant was taken for measurement of UV-VIS spectroscopy and CE.

Determination of antazoline and tetrahydrozoline in ophthalmic solutions by capillary electrophoresis and stability-indicating HPLC methods.

Capillary electrophoretic (CE) and high performance liquid chromatographic (HPLC) methods were developed and optimized for the determination of antazoline (ANT) and tetrahydrozoline (TET) in ophthalmic formulations. Optimum electrophoretic conditions were achieved using a background electrolyte of 20mM phosphate buffer at pH 7.0, a capillary temperature of 25°C, a separation voltage of 22 kV and a pressure injection of the sample at 50 mbar for 17s.

L-Cysteine capped Mn-doped ZnS quantum dots as a room temperature phosphorescence sensor for in-vitro binding assay of idarubicin and DNA.

L-cysteine capped Mn doped ZnS quantum dots/ Idarubicin (IDA) nanohybrids were used as novel room temperature phosphorescence (RTP) sensor to detect double stranded deoxyribonucleic acid (ds-DNA)/drug interaction. IDA, anthracycline derivative anticancer drug, was adsorbed on the surface of the QDs as an electron acceptor to quench the RTP emission. The RTP intensity of QDs was quenched quickly upon addition of quencher and the reaction reached equilibrium within 2 min.

Determination of parabens in human milk and other food samples by capillary electrophoresis after dispersive liquid-liquid microextraction with back-extraction.

Dispersive liquid-liquid microextraction (DLLME) with back-extraction was used prior to capillary electrophoresis (CE) for the extraction of four parabens. Optimum extraction conditions were: 200 μL chloroform (extraction solvent), 1.0 mL acetonitrile (disperser solvent) and 1 min extraction time.

Dispersive liquid-liquid microextraction combined with field-amplified sample stacking in capillary electrophoresis for the determination of non-steroidal anti-inflammatory drugs in milk and dairy products.

Dispersive liquid-liquid microextraction (DLLME) was coupled with field-amplified sample stacking in capillary electrophoresis (FASS) for the determination of five non-steroidal anti-inflammatory drugs (NSAIDs) in bovine milk and dairy products. After extraction, the enriched analytes were back-extracted into a basic aqueous solution for injection into CE. Under optimum conditions, enrichment factors were in the range 46-229.

Dispersive liquid-liquid microextraction based on solidification of floating organic drop combined with field-amplified sample injection in capillary electrophoresis for the determination of beta(2)-agonists in bovine urine.

Dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) was for the first time combined with field-amplified sample injection (FASI) in CE to determine four β(2)-agonists (cimbuterol, clenbuterol, mabuterol, and mapenterol) in bovine urine. Optimum BGE consisted of 20 mM borate buffer and 0.1 mM SDS.

Ultrasound-assisted emulsification microextraction for the determination of ephedrines in human urine by capillary electrophoresis with direct injection. Comparison with dispersive liquid-liquid microextraction.

Ultrasound-assisted emulsification microextraction and dispersive liquid-liquid microextraction were compared for extraction of ephedrine, norephedrine, and pseudoephedrine from human urine samples prior to their determination by capillary electrophoresis. Formation of a microemulsion of the organic extract with an aqueous solution (at pH 3.2) containing 10% methanol facilitated the direct injection of the final extract into the capillary.

Determination of tin by in situ trapping of stannane on a resistively heated iridium treated tungsten coil surface and interference studies.

A novel method was developed for the in situ trapping of stannane on an iridium-coated tungsten coil. Coating the tungsten coil with iridium has significantly improved the sensitivity. The tungsten coil can either be used as an on-line atomizer or as a trapping surface.

Determination of 7-ethoxyresorufin-o-deethylase (EROD) induction in leaping mullet (Liza saliens) from the highly contaminated Aliaga Bay, Turkey.

Pollution of the aquatic environment is a global concern owing to the devastating effects of contaminants whose levels are growing at an alarming rate, and it has become a major threat for marine organisms, as well as to humans as consumers. This study has been carried out on leaping mullet obtained from Aliaga Bay, which is located on the west coast of the Aegean Sea near Izmir and hosts the world's fifth largest shipyard, plus a broad range of industrial activities, including an oil refinery and a paper factory. The waste from these industries, combined with municipal sewer discharges, is the main cause of pollution in this region.

Electrochemically controlled solid-phase microextraction (EC-SPME) based on overoxidized sulfonated polypyrrole.

A method for the extraction and selective determination of cations is proposed using electro-synthesized overoxidized sulfonated polypyrrole film. The polymer film is used for the selective extraction of trace levels of nickel and cadmium ions by solid-phase microextraction (SPME). The cation uptake and release properties of the overoxidized sulfonated polypyrrole film electrode were examined under both open circuit and controlled potential conditions for prospective applications in electrochemically controlled solid-phase microextraction.

Determination of lead in dialysis concentrates using flow injection hydride generation atomic absorption spectrometry.

Flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) was used for determination of lead in dialysis concentrates. The parameters such as acidity, concentration of oxidising and reducing agents and argon gas flow rate were investigated to reach the best peak height sensitivity. No significant background signal was observed at high salt concentrations.

Mercury exposure in dental practice.

Since elemental mercury is absorbed by dental professionals through direct skin contact or inhalation, the use of mercury in dental amalgam continues to be a controversial issue. In this study, the authors address the possible health risk of occupational exposure to mercury vapor in the dental office. The cytogenetic examination of leukocytes with alkaline comet assay and blood mercury levels with Atomic Absorption Spectrometer of dentists exposed to mercury vapor below 0.

Direct-write fabrication of functional protein matrixes using a low-cost Q-switched laser.

We report the use of an inexpensive, small, and "turn-key" Q-switched 532-nm Nd:YAG laser as a source for nonlinear, direct-write protein microfabrication. In this approach, microJoule pulses (pulse widths, approximately 600 ps) are focused using high numerical aperture optics to submicrometer focal spots, creating instantaneous intensities great enough to promote multiphoton excitation of a photosensitizer and subsequent intermolecular cross-linking of protein molecules. By scanning the femtoliter focal volume through reagent solution, extended protein-based structures can be fabricated with precise, three-dimensional topographies.

Quantitative determination of ketoprofen in gels and ampules by using flow-injection UV spectrophotometry and HPLC.

A flow-injection UV spectrophotometric method for the determination of ketoprofen in gels and ampules was developed. Quantitative determination of ketoprofen was realized by using distilled water as a carrier for gels and citrate buffer, pH 6.5, for ampules at 261 nm.

Assessment of abnormal DNA repair responses and genotoxic effects in lead exposed workers.

Background: One of the main sources of occupational exposure to lead (Pb) in Turkey is in workers of battery industries. Genotoxic studies in human populations exposed to this metal have had conflicting results.

Methods: Genotoxic effects of Pb were studied in blood cell samples from workers of battery manufactures exposed to Pb compounds by chromosomal aberration (CA) assay and X-ray induced challenge (XRC) assay to assess DNA damage and interference with DNA repair processes after an in vitro exposure of X-ray (1 Gy).

Assessment of cytogenetic damage in lymphocytes and in exfoliated nasal cells of dental laboratory technicians exposed to chromium, cobalt, and nickel.

Dental laboratory technicians may be exposed to metal alloys that are used in the production of crowns, bridges and removable partial dentures. These alloys consist of 35-65% cobalt, 20-30% chromium, 0-30% nickel, and small amounts of molybdenum, silica, beryllium, boron and carbon. The aim of this study was to assess whether dental technicians are occupationally exposed to chromium, cobalt and nickel, by analyzing urinary excretion levels of these metals and to investigate the genotoxic effects of occupational exposure associated with dental prostheses production operations by analyzing cytokinesis-blocked micronucleus (CB-MN) frequencies in peripheral lymphocytes and micronucleus (MN) frequencies in exfoliated nasal cells from 27 dental laboratory technicians and 15 control subjects.