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A new spectrophotometric protocol was developed for the simultaneous determination of soluble Mn(III), Mn(II) and total Mn [sum of soluble Mn(III) and Mn(II)] in sediment porewaters using a water soluble meso-substituted porphyrin [α,β,γ,δ-tetrakis(4-carboxyphenyl)porphine (T(4-CP)P)]. A simple kinetic rate model is used to quantify soluble Mn(II), Mn(III) and total Mn concentrations during a metal...
We describe a solid-phase extraction (SPE) method, followed by gas chromatography–mass spectrometry (GC–MS), for the simultaneous determination of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in sheep serum samples. The denaturation of serum proteins by formic acid, water-1-propanol and water-2-propanol were compared and optimized. Seven different solid-phase sorbents...
We have demonstrated the design of a new type fluorescence assay based on the inner filter effect (IFE) of gold nanoparticles (AuNPs) on the fluorescence of quantum dots (QDs). With a high extinction coefficient, AuNPs are expected to be capable of functioning as powerful absorbers. QDs with tunable emission wavelength are ideal fluorophores because the emission spectra of the rationally synthesized...
The strength of the interaction between a pesticide and the soil organic matter is a key parameter to assess the risk of it reaching to groundwater with potentially harmful effects to human health. In this work, a new approach that allows measuring such interactions in a few minutes using a purified fraction of the soil organic matter (humic substances) is detailed. The strength of sorption is assessed...
A procedure for the quantitative determination of diclofenac sodium (DS) in commercial capsules and tablets based on Partial Least Squares (PLS) treatment of diffuse reflectance FTIR spectroscopic (DRIFTS) data is described. Two DRIFTS accessories, a Collector II (Spectra-Tech) and a Seagull (Harrick Scientific), were used to collect the spectra. The spectrometer beam area on the surface of the sample...
The interaction between mercaptoacetic acid (MA)-capped CdTe QDs, MA-capped CdTe/ZnS QDs or glutathione (GSH)-capped CdTe QDs with As(III) was studied using fluorescence spectrometry. As (III) has a high-affinity to reduced-GSH to form As(SG) 3 , and the emission of the GSH-capped CdTe QDs (λ em. =612nm) is quenched effectively. Thus, a novel fluorescence spectrometric method was developed...
In this paper, the potential use of multiwalled carbon nanotubes (MWCNTs) as solid phase extraction (SPE) adsorbent was evaluated for preconcentration of linear alkylbenzene sulfonates (LAS) using ion-pair (IP)-SPE with tetrabutylammonium hydroxide (TBAH). The LAS homologues present in the aqueous sample were ion-paired with TBAH and the solution was passed through the MWCNT cartridges. The analytes...
In this paper, the influence of several operational parameters on a well established multiresidue LC–MS/MS method has been studied in relation to the analysis of 150 pesticides commonly present in vegetable samples. The operational parameters investigated are: (i) the influence of different modifiers (0.1% formic acid; 5mM ammonium formiate; 5mM ammonium acetate in aqueous phase) – both on the retention...
In this article, the radical-scavenging capacity of phenol fractions extracted from the brown seaweed Ascophyllum nodosum was assessed using in parallel colorimetric methods (ABTS and DPPH) and electrochemistry (cyclic voltammetry). Results obtained by the three methods correlated in the case of global fractions, whereas only ABTS and DPPH correlated when activities were expressed on a phenol basis...
Metal oxide nanoparticles prepared by pulsed laser deposition (PLD) were applied to nonenzymatic glucose detection. NiO nanoparticles with size of 3nm were deposited on glassy carbon (GC) and silicon substrates at room temperature in an oxygen atmosphere. Transmission electron microscope (TEM) image showed nanoparticles with the size of 3nm uniformly scattered on the Si(001) substrate. Unlike co-sputtering...
An electrochemical strategy on the basis of rationally designed molecularly imprinted sol–gel polymer embedded with gold nanoparticles (AuNPs) is developed for the specific and sensitive determination of Sudan I. The rationally designed sensing Sudan I imprinted sol–gel was prepared by mixing Sudan I with 3-aminopropyltriethoxysilane, tetraethoxysilane, chitosan, and AuNPs, followed by copolymerization...
An automatic gas-phase molecular absorption spectrometric (GPMAS) system was developed and applied to determine nitrite and total nitrate in water samples. The GPMAS system was coupled with a UV-light emitting diode photodiode (UV-LED-PD) based photometric detector, including a 255nm UV-LED as the light source, a polyvinyl chloride (PVC) tube of 14cm as the gas flow cell, and an integrated photodiode...
The comparison of theoretical approaches describing the collection of analyte in the cylindrical wet effluent diffusion denuder (CWEDD) with experimental data is presented. Various absorption liquids were tested for the collection of formaldehyde (distilled-deionized water, H 2 SO 4 solution), acetaldehyde (distilled-deionized water) and nitrous acid (distilled-deionized water, sodium...
This work reports a fast and simple liquid chromatographic method for the simultaneous determination of five banned fat-soluble synthetic colorants, namely Sudan I–IV and Para-Red, in spice samples. The analytes were successfully separated isocratically in less than 5min on the new narrow bore monolithic column, FastGradient ® Chromolith (50mm×2.0mm i.d.) using a mobile phase of 0.1% (v/v)...
The performance of 5cm long narrow-bore columns packed with 2.6–2.7μm core–shell particles and a column packed with 1.7μm totally porous particles was compared in very fast gradient separations of polar neutral active pharmaceutical compounds. Peak capacities as a function of flow-rate and gradient time were measured. Peak capacities around 160–170 could be achieved within 25min with these 5cm long...
The determination of six phthalate acid esters was achieved in artificial saliva using gas chromatography–mass spectrometry following activated carbon enrichment of samples. Central composite experimental design was applied to optimize method parameters, such as pH, adsorption time and amount of activated carbon. The best compromise of analytical conditions for the simultaneous determination of analytes...
An electrochemical approach for the sensitive detection of sequence-specific DNA has been developed. Horseradish peroxidase (HRP) assembled on the Fe 3 O 4 nanoparticles (NPs) were utilized as signal amplification sources. High-content HRP was adsorbed on the Fe 3 O 4 NPs via layer-by-layer (LbL) technique to prepare HRP-functionalized Fe 3 O 4 NPs....
This paper reports an analytical method for rapid determination of neptunium ( 237 Np) in environmental solid samples exploiting automated sequential injection (SI)-based anion exchange separation. Pivotal issues on analytical method performance were investigated including sorption behavior of 237 Np onto various AG 1-type anion exchangers; suitability of 242 Pu as a tracer...
We have developed a fluorescence technique for the detection of Hg 2+ and Pb 2+ ions using polythymine (T 33 )/benzothiazolium-4-quinolinium dimer derivative (TOTO-3) and polyguanine (G 33 )/terbium ions (Tb 3+ ) conjugates, respectively. Hg 2+ ions induce T 33 to form folded structures, leading to increased fluorescence of the T 33 /TOTO-3...
Isothermal titration calorimetry (ITC) is used to study the complexation thermodynamics of Ni(II) with histidine (His) and with N-2-aminoethylglycine (EDMA). The titrations were performed in HEPES and Tris buffers at various ionic strengths and pH values around 8. The results show the influence of the experimental conditions on the shape and fitting parameters of the calorimetric curves. For the studied...
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