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A phenobarbital containing polymer/ silica coated quantum dot composite for the selective recognition of mercury species in fish samples using a room temperature phosphorescence quenching assay
摘要： An analytical procedure using low-cost instrumentation (fluorescence/phosphorescence spectrophotometer) has been developed to assess total mercury in fishery products. Determinations were based on the room temperature phosphorescence (RTP) quenching of a composite Ph-QDs consisting of phenobarbital-containing polymer/silica coated Mn-doped ZnS quantum dots. Under optimum conditions (fish extract pH of 8.0, Ph-QDs concentration of 20 mg L?1, and an interaction time of 12 min), the material offers high selectivity for inorganic mercury and methyl-mercury over other common ions present in the fish matrix. Moreover, good linearity was obtained for mercury concentrations within the 0–100 μg L?1 range, and the obtained limit of detection (68.2 μg kg?1) is low enough for a reliable assessment of total mercury in fish and seafood samples. The developed method was found to be free of matrix effects, and offers the advantage that the fish extracts can be directly analysed even at a 1:10 dilution. The method was found to be accurate after analysing a fish certified reference material, and after comparing total mercury levels in a set of fish samples analysed by the proposed chemosensor probe and by inductively coupled plasma mass spectrometry after an acid decomposition sample pre-treatment.
关键词： Room temperature phosphorescence,Phenobarbital,Fish,Mercury,Quantum dots
更新于2025-09-19 17:13:59
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Photoelectrochemical properties of Ba2TiO4 prepared by nitrate route. Application to electro-photocatalysis of phenobarbital mineralization by solar light
摘要： Ba2TiO4 elaborated from nitrates decomposition crystallizes in a monoclinic perovskite structure with a crystallite size of 66 ± 2 nm and is applied for the environmental protection. The oxide is characterized by scanning electron microscopy, diffuse reflectance and photo-electrochemistry; an indirect transition at 3.34 eV is determined. The electrical conductivity follows an exponential law: σo exp (-0.40 eV/kT) and the conduction occurs by small polarons hopping through mixed valences Ti4+/3+ with a semi conductor behavior. The intensity ?2 M, pH ～ 6) exhibits a small hysteresis similar to a chemical diode. potential J(E) characteristic in Na2SO4 (10 The capacitance measurement recorded at pH ～ 6 indicates and n-type behavior, due to oxygen vacancies and gives a flat band potential of 0.74 VSCE. As application, the phenobarbital is successfully oxidized by electro-catalysis on Ba2TiO4 with a conversion rate of 55% under an electric current of 120 mA. An enhancement up to 66% has been obtained by electro-photocatalysis under solar illumination. The phenobarbital elimination follows a first order kinetic with a rate constant of 3.22 × 10-3 mn-1 and a reaction mechanism is suggested.
关键词： Perovskite,Solar light,Electro-photocatalysis,Phenobarbital,Ba2TiO4
更新于2025-09-09 09:28:46