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In this study a novel biosensor for determination of taxol is described. The interaction of taxol with salmon-sperm double-stranded DNA (ds-DNA) based on the decreasing of the oxidation signals of guanine and adenine bases was studied electrochemically with a pencil-graphite electrode (PGE) using a differential pulse voltammetry (DPV) method. The decreases in the intensity of the guanine and adenine...
Gastric carcinoma is the most malignant tumor. Due to lacking of efficient means to diagnose the cancer at the early stage, it is necessary to develop effective molecular probes for early diagnosis and treatment. We have selected aptamers with high specificity and affinity against SGC7901 cells by cell-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) method, which shown important...
A novel dispersive micro solid phase extraction (DMSPE) cleanup method based on the PCX sorbent (a kind of cation exchange polymer material) was applied to the analysis of melamine and cyromazine residues in milk and milk powder, and ultra high performance liquid chromatography-high resolution mass spectrometry (UHPLC–HRMS) was used as instrument detection. Milk powder samples were first extracted...
Musk compounds are widely used as fragrances in personal care products. On account of their widespread use and their low biodegradation, they can be found in environmental samples. In our study two extraction methodologies were compared and different clean-up strategies were also studied in order to develop a reliable analytical method, with minimum matrix effect and good detection limits, to determine...
A new magnetic solid phase extraction (MSPE) method using octyl-immobilized silica-coated magnetic Fe3O4 (C8-Fe3O4@SiO2) nanoparticles as the MSPE adsorbent combined with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for speciation analysis of Sb(III) and Sb(V). At pH 5.0, Sb(III) forms a hydrophobic complex with ammonium pyrrolidine dithiocarbamate (APDC) and is retained...
Given its high sensitivity and non-destructive nature, fluorescence excitation–emission matrix (EEM) spectroscopy is widely used to differentiate changes and transformations of dissolved or water-extracted organic matter (OM) in natural environments. The same technique applied directly on solid samples (solid-phase fluorescence spectroscopy, SPF-EEM) provides accurate results when used with pharmaceutical...
Many studies have been carried out to identify dissolved organic matter–trace metals interactions, as organic matter (OM) was demonstrated to be a governing parameter of metals speciation. Concerning arsenic (As), such OM–As studies are scarce and concluded that, when As binding occurred, it was probably through cationic bridges or, in some cases, directly. Yet, analytical proofs remained complex...
Carbon dots capped with polyethyleneimine (CD-PEI) were synthesized and applied in selective separation and preconcentration of trace Cr(VI). Dispersed particle extraction (DPE) slurry sampling with flame atomic absorption spectrometry (FAAS) was used to selectively and sensitively determine Cr(VI) in water samples. The as-synthesized CD-PEI was confirmed by Fourier transform infrared spectroscopy,...
In this work, the oxazine 170 perchlorate (O17)-ethyl cellulose (EC) membrane was successfully applied in the fabrication of a urea-sensing membrane. The urea-sensing membrane was a double layer consisting of the O17-EC membrane and a layer of the enzyme urease entrapped into EC matrix. The sensing principle of urea was based on the hydrolysis reaction of urea under the catalysis of the urease to...
An electrochemical immunoassay for neopterin was developed using recently produced specific antibodies immobilized to protein A-coated magnetic beads in combination with differential pulse voltammetry and screen-printed array of electrodes. Neopterin–alkaline phosphatase conjugate was used as label in a competitive assay format. Multiplexed analysis of neopterin was demonstrated by replacing the traditional...
In this work a multivariate statistical tool (Derringer and Suich optimization) was proposed for the separation of seventeen capsinoids (natural and synthetic) using the UHPLC-DAD chromatography. Capsinoids were analyzed at 280nm. The variables optimized were the mobile phase (water (0.1% acetic acid as solvent A) and acetonitrile (0.1% as solvent B)), gradient time and flow rate. Two columns with...
A compact fluorescence detector was constructed on a microchip from an organic light emitting diode (OLED) as the light source and an organic photodiode (OPD) as the photo-detector and was used in an immunoassay for alkylphenol polyethoxylates (APE). The OLED based on a terbium complex emitted a sharp light at the main wavelength of 546nm with a full width at half maximum of 9nm. The incident photo-to-current...
Recent advances in electrochemical analysis on filter paper exemplify the versatility of this substrate for high performance testing. Its low-cost, light-weight, and environmentally friendly properties make it particularly attractive for applications in addressing health and environmental safety needs in low-resource settings and developing countries. However, the main drawback to sensitive electrochemical...
This paper presents a new method for the determination of imidacloprid in water samples; one of the most widely used neonicotinoid pesticides in the farming industry. The method is based on the measurement of excitation–emission spectra of photo-induced fluorescence (PIF-EEMs) associated with second-order multivariate calibration with a parallel factor analysis (PARAFAC) and unfolded partial least...
The selection of two high performance liquid chromatography (HPLC) columns with vastly different retention mechanisms is vital for performing effective two-dimensional (2D-) HPLC. This paper reports on a systematic method to select a pair of HPLC columns that provide the most different separations for a given sample. This was completed with the aid of a HPLC simulator that predicted retention profiles...
Data fusion is the process of combining data gathered from two or more sensors to produce a more specific, comprehensive and unified dataset of the inspected target. On this basis, much has been said about the possible benefits resulting from the use of molecular and atomic information for the detection of explosives. The orthogonal nature of the spectral and compositional information provided by...
A porous silicon/palladium nanostructure was prepared and used as a new electrode material for the simultaneous determination of acetaminophen (ACT) and codeine (COD). Palladium nanoparticles were assembled on porous silicon (PSi) microparticles by a simple redox reaction between the Pd precursor and PSi in an aqueous solution of hydrofluoric acid. This novel nanostructure was characterized by different...
Chemical metrology is gaining importance in electronics industry that manufactures semiconductors, electronic displays, and microelectronics. Extensive and growing needs from this industry have raised the significance of accurate measurements of the amount of substances and material properties. For the first time, this paper presents information on how chemical metrology is being applied to meet a...
A new homogeneous immunoassay for the detection of progesterone was developed to measure its concentration in human serum. We utilized the weak cross-reactivity of a monoclonal anti-progesterone antibody to an analog molecule (in this case β-estradiol) to create a mixture, in which the fluorescence-labeled antibody (AbF) and quencher-labeled BSA-estradiol (eBSAq) were at optimized equilibrium. At...
In this study, a facile hydrothermal method was developed to synthesize Pt-on-Pd supported on reduced graphene oxide (Pt-on-Pd/RGO) hybrids. Because of the synergistic effect between Pt-on-Pd and RGO, the obtained Pt-on-Pd/RGO had superior peroxidase-mimic activities in H2O2 reduction and TMB oxidation. The reaction medium was optimized and a sensing approach for H2O2 was developed with a linear range...
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