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This study describes a method for coupling dispersive liquid–liquid microextraction (DLLME) and normal-phase liquid chromatography (NP-LC) with fluorescence detection for vitamin A determination with the view to developing a new green sample preparation technique. Parameters affecting DLLME, including the nature and volume of both extractant and disperser solvents, salt addition and time and speed...
In this work, a self-assembled diazonium modified gold electrode (D-MGE) was used for the fabrication of an electrochemical DNA biosensor. For preparation of D-MGE, initially 2-amino-5-mercapto-1, 3, 4-thiadiazole (AMT) self-assembled on gold electrode and a simple diazonation reaction was used to prepare D-MGE. Then, non-labeled single strand DNA (NL-ssDNA) directly was immobilized on D-MGE through...
Individual and simultaneous electrochemical detection of iodide and iodine has been performed via cyclic voltammetry on boron doped diamond (BDD) electrodes in a 1M NaClO 4 (pH 8) solution, representative of typical environmental water conditions. It is feasible to compute accurate calibration curve for both compounds using cyclic voltammetry measurements by determining the peak current intensities...
A novel sample pre-treatment method for multi trace element enrichment from environmental waters prior to optical emission spectrometry analysis with inductively coupled plasma (ICP-OES) is proposed, based on dispersed particle extraction (DPE). This method is based on the use of silica nanoparticles functionalized with strong cation exchange ligands. After separation from the investigated sample...
The gunpowder age is information of great importance that could help to establish safety regulations related to the propellants use and manipulation. In this work, a forced aging treatment (65°C for 120 days) was applied to four gunpowders stabilized with diphenylamine (DPA). The evolution of DPA and derivatives (N-nitroso-DPA, 2-nitro-DPA, 4-nitro-DPA, and 4-4′-dinitro-DPA) concentration during the...
A miniaturized solid phase extraction procedure has been developed for ultra-trace determination of inorganic arsenic species. Arsenic(III) as pyrrolidinedithiocarbamate complex was selectively adsorbed on 30mg poly(hydroxyethyl methacrylate) (PHEMA) micro beads, which is simply packed into a micro-pipette-tip. The adsorbed arsenic was quantitatively eluted by 700μL 0.25M NH 3 and determined...
A fingerprinting approach was developed by means of UPLC–ESI/MS n (ultra-performance liquid chromatography–electrospray ionization/mass spectrometry) for the quality control of processed Radix Aconiti, a widely used toxic traditional herbal medicine. The present fingerprinting approach was based on the two processing methods recorded in Chinese Pharmacopoeia for the purpose of reducing the...
The interaction of ciprofloxacin (Cf) with double-stranded DNA was studied by cyclic voltammetry, fluorescence emission spectroscopy, and UV–Vis spectroscopy. The presence of DNA results in a decrease in the current and a positive shift in the Cf oxidation peak indicates the intercalative interaction. The corresponding heterogeneous rate constant (k s ) and the electron transfer coefficient...
A polyfunctional low-capacity cation-exchange column-packing material was developed for the simultaneous separation and determination of underivatized 20 amino acids including 16 proteinogenic ones using a binary gradient HPLC. The new packing material was prepared by sulfoacylating a highly crosslinked macroreticular poly(styrene-divinylbenzene) copolymer of 3μm in diameter commercially available...
The possibility of simultaneously determining seven concerned heavy polycyclic aromatic hydrocarbons (PAHs) of the US-EPA priority pollutant list, in extra virgin olive and sunflower oils was examined using unfolded partial least-squares with residual bilinearization (U-PLS/RBL) and parallel factor analysis (PARAFAC). Both of these methods were applied to fluorescence excitation emission matrices...
In the present work, a new, simple and efficient method for simultaneous preconcentration of ultra-trace amounts of gold and thallium is developed using an ion pair based-ultrasound assisted emulsification-solidified floating organic drop microextraction procedure before graphite furnace atomic absorption spectrometry determination. This methodology was used to preconcentrate the ion pairs formed...
The aptamer immbolization onto organized mixed layers of diazonium salts via click chemistry was explored. The immobilized aptamer was employed in the fabrication of a highly sensitive and reusable electrochemical impedimetric aptasensor for the detection of ochratoxin A (OTA). The screen-printed carbon electrodes (SPCEs) were first modified by electrografting of a protected 4-((trimethylsilyl)ethynyl)...
Sixty one volatile organic compounds (VOCs) from a standard gas mixture were separated via isothermal gas chromatography coupled with time-of-flight mass spectrometry (GC–TOFMS) in a ∼35s separation time window (∼45s separation). The VOCs in the standard gas mixture were selected based on the EPA TO-15 methodology. The high throughput separation was achieved with a relatively high total peak capacity...
Sample purification can be considered the most polluting step of the whole analytical process for PCBs determination in sediment samples. The use of photochemical sample treatment represents an alternative methodology for extracts clean up allowing for a reduction of the used amount of organic solvents. The first application of a photochemical sample treatment for the selective removal or reduction...
Noninvasive standoff deep Raman spectroscopy has been utilised for the detection of explosives precursors in highly fluorescing packaging from 15m. To our knowledge this is the first time standoff deep Raman spectroscopy of concealed substances in highly fluorescing coloured packaging is demonstrated. Time-resolved Raman spectroscopy, spatially offset Raman spectroscopy and time-resolved spatially...
Nontarget analysis means that a sample is analysed without preselection of the studied analytes. While target analysis attempts to determine whether certain selected compounds are present in the sample, nontarget analysis is performed to explore what unknown compounds can be found. We developed a nontarget method using a landfill leachate sample as a complex test sample. The method was based on the...
The heat stress response of Escherichia coli at various temperatures has been investigated using NiO nanoparticles assisted MALDI–TOF-MS. Significant numbers of protein peaks were obtained in the presence of NiO NPs when the samples were incubated at various temperatures in comparison with the control E. coli suspension (10 7 cfu/mL). The 10kDa chaperonin (groES) is the principal protein operating...
In the present work, sensitive and stable sandwiched electrochemical immunosensing strategies with graphene (Gr)/gold nanoparticles (GNP) composite as the immobilization platform and ferrocene (Fc) derivatives as labels were proposed. Under the optimal choice and the proposed immunosensing strategy, with 1,1′-ferrocenedicarboxylic acid label, the human IgG could be detected specifically with a low...
This study developed a sensitive and selective aptamer-based chemiluminescent (CL) method for the determination of platelet-derived growth factor (PDGF)-BB using hydroxylamine enlarged gold nanoparticles (Au NPs). Rabbit anti-human PDGF-BB polyclonal antibody was covalently coupled on the 96-well plate that offers reactive N-oxysuccinimide ester (referred to as NOS group) surface. In the presence...
An algorithm, referred to as targeted mass spectral ratio analysis (TMSRA) is presented whereby the ratios between intensities as a function of mass channel (m/z) of a target analyte mass spectrum are used to automatically determine which m/z are sufficiently pure to quantify the analyte in a sample gas chromatogram. The standard perfluorotributylamine (PFTBA) was used to evaluate the reproducibility...
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