Study of a Novel Bisnaphthalimidopropyl Polyamine as Electroactive Material for Perchlorate‐selective Potentiometric Sensors

In this work, the new polyamine bisnaphthalimidopropyl‐4,4’‐diaminodiphenylmethane is proposed as a new ionophore for perchlorate potentiometric sensors. The optimal formulation for the membrane comprised of 12 mmol kg^?1 of the ionophore, and 68 % (w/w) of 2‐nitrophenyl phenyl ether as plasticizer and 31 % (w/w) of high molecular weight PVC. The sensors were soaked in water for a week to allow leakage of anionic impurities and for one day in a perchlorate solution (10^?4 mol L^?1) to improve reproducibility due to its first usage. The stability constant for the ionophore‐perchlorate association in the membrane, log β_IL1=3.18±0.04, ensured a performance characterized by the slope of 54.1 (±0.7) mV dec^?1 to perchlorate solutions with concentrations between 1.24×10^?7 and 1.00×10^?3 mol L^?1. The sensors are insensitive to pH between 3.5 to 11.0, they have a practical detection limit of 7.66 (±0.42) ×10^?8 mol L^?1 and a response time below 60 s for solutions with perchlorate concentrations above 5×10^?6 mol L^?1. The accuracy of the results was confirmed by the analysis of the contaminant in a certified reference water sample.     

基于共价有机骨架材料的磁固相萃取-超高效液相色谱-串联质谱法测定水中4种杀菌剂

杀菌剂在环境中长期富集后会引起土壤和植物病害,并能借助雨水或灌溉渗透到深层土壤和地下水中,威胁水体环境和人体健康。因此针对水中杀菌剂开发简单快速、高效灵敏的分析方法至关重要。该研究通过原位合成法制备了磁性共价有机骨架材料Fe₃O₄@TpBD,将其作为萃取吸附剂,富集环境水体中苯并咪唑杀菌剂(噻菌灵、麦穗宁、多菌灵)和有机硫杀菌剂(稻瘟灵)。利用Fe₃O₄@TpBD与杀菌剂之间的π-π共轭、氢键和静电作用进行吸附,结合超高效液相色谱-串联质谱法(UHPLC-MS/MS)进行检测,建立了测定水中4种痕量杀菌剂的分析方法。通过透射电子显微镜、X射线衍射及傅里叶变换红外光谱等方式对Fe₃O₄@TpBD进行表征,以证明材料的成功合成。对萃取条件进行一系列的优化(Fe₃O₄@TpBD的磁性比例及用量、水样pH、吸附时间、洗脱液的种类及体积、洗脱时间、NaCl含量),确定了最佳萃取条件。4种杀菌剂在3~1200 ng/L的范围内线性关系良好,线性相关系数均大于0.998,方法的检出限和定量限分别为0.06~0.28 ng/L和0.20~0.92 ng/L。在15、150和600 ng/L 3个加标水平下进行加标回收试验,日内和日间精密度分别为2.8%~10.0%和4.4%~15.7%。将该方法用于实际水样的检测,4种杀菌剂的加标回收率为77.1%~119.1%,在水库水中检测出多菌灵,含量为27.5 ng/L。该方法灵敏度高,准确度和精密度良好,操作简单,耗时短。     

Stripping Analysis of Trace Metals at a Flow-Through Reticulated Vitreous Carbon Electrode after the Preconcentration by Supported Liquid Membrane Technique

Abstract

The performance of a flow-through mercury coated reticulated vitreous carbon (RVC) electrode in the potentiometric stripping analysis (PSA) of trace metals has been examined. A wall-jet glassy carbon cell was used for the comparative experiments. Experimental parameters influencing the stripping signals have been optimised in order to use the stripping analysis after the preconcentration and matrix isolation by supported liquid membrane (SLM) technique. The SLM with di-2-ethylhexyl-phosphoric acid (DEHPA) as the extractant in the membrane liquid for proton driven transport of trace metals across the membrane has been chosen. Results presented for lead determination in river water demonstrate the analytical advantages of coupled technique SLM-PSA.     

In Situ Correlations Between Polycyclic Aromatic Hydrocarbons (PAH) and Pah Metabolizing System Activities in Mussels and Fish in the Mediterranean Sea: Preliminary Results

Abstract

Biochemical indices based on enzymatic activities have been determined in fish and mussels sampled in various different coastal locations in the Mediterranean Sea. Preliminary results show a good agreement between biochemical measurements in marine organisms and chemical analyses of polycyclic aromatic hydrocarbons present in sediments. The results obtained suggest the use of biochemical indices for application in chemical contaminant biomonitoring.     

Determination of Uranium in Natural Waters by Solid Phase Spectrometry

Abstract

A microdetermination method (at the μg1^?1 level) for uranium has been developed, based on Solid-Phase Spectrophotometry (SPS). The uranium reacts with pyridylazo-resorcinol in the presence of fluoride to form a 1:1:1 red ternary complex, which is fixed on an anion-exchange resin. The resin absorbance is measured directly, and allows the determination of uranium in the range of 1–10μg1^?1, with an RSD of 4%. The method has been applied to the determination of U(VI) in natural waters from wells located near the deposits of industrial wastes from a uranium mineral plant in Andujar (Spain).     

Isotope Zusammensetzung Der Mineralwässer Der Mongolei

Abstract

The isotopic composition (D, ¹⁸O, ⁸⁷Sr, ³He) of thermal and mineral waters of Mongolia is discussed. The Sr-isotope ratio depends on the rock's contact. Near the Chubsugul-lake ³He-/⁴He-values are high. A certain similarity between the waters of Mongolia and those of East Siberia can be derived from the obtained data.     

Halocarbons in Antarctic Surface Waters

Abstract

Surface water samples taken during the 1988–89, 1989–90 and 1990–91 Italian expeditions were analyzed for the presence of carbon tetrachloride, trichloroethylene and tetrachloroethylene. The sample analysis was carried out by solvent extraction and capillary GC-ECD-MS determination. The above-mentioned halocarbons were at ng/l level in all water samples investigated.     

Matrix Isolation Infrared Spectra of Methylacetate III. UV-Induced Z→E photorotamerisation of Methylacetate in Argon Matrices

Abstract

Broadband UV-irradiation of methylacetate isolated in argon matrices causes rather strong modifications to appear in the IR spectrum. Evidence was obtained for a photochemical interconversion of the stable Z-conformer into the less stable E-conformer followed by photolytic decomposition of the latter into stable products. Most of these products could be identified from their IR absorptions. The reverse E→Z interconversion is a thermal process with an activation energy of about 10 kJmole^?1. A normal coordinate analysis based on a transferable valence force field obtained from the literature allowed to assign approximate IR frequencies of E-methylacetate.     

Ion Chromatographic Determination of Selected Anions in Mineral Waters

Abstract

Suppressed ion-chromatography using Na₂CO₃/NaHCO₃ as eluent was applied to the determination of chloride, sulphate, nitrate and bromide in highly mineralised waters. The effect of different concentrations of hydrogen carbonate on the retention times of the determination of the four selected anions was studied. Depending on the total concentration of ionic species, dilution of the sample is recommended to obtain retention times approaching those of the anion standard. The stability of sample composition was not affected by the presence of iron(III) ions (up to 15 mgL^?1).     

Determination of Hg(II) in Environmental Water Samples by Dispersive Liquid Phase Microextraction Combined with Flame Atomic Absorption Spectrometry

In this study, a method of dispersive liquid phase microextraction combined with the flame atomic absorption spectrometry was proposed for the determination of trace Hg using diphenylthiocarbazone as chelating reagent. Several factors which have effect on the microextraction efficiency of Hg, such as pH, extraction and dispersive solvent type and their volume, concentration of the chelating agent, extraction time were investigated, and the optimized experimental conditions were established. After extraction, the enrichment factor was 68. The detection limit of the method was 45 ng mL^?1, and the relative standard deviation for eight determinations of 2 μg mL^?1 Hg was 1.7%. The results for the determination of Hg in environmental water samples (tap water, well water, mineral water and Caspian sea water) have demonstrated the applicability of the proposed method.