Study on the fluorescence characteristics of bromadiolone in aqueous and organized media and application in analysis

The fluorescence spectroscopic behavior of bromadiolone (anticoagulant rodenticide), a substituted 4-hydroxycoumarin derivative, was investigated in water and in organized media like micelles and cyclodextrins. A detailed study on various photophysical parameters like fluorescence intensity (I_F), quantum yield (), lifetime (τ) and steady state fluorescence anisotropy (r) of bromadiolone in aqueous and in organized media was carried out. Bromadiolone in aqueous solution was observed to be in an aggregated state, thereby showing weak emission due to self-quenching. Marked enhancement of fluorescence intensity was observed in organized media like micelles and β-cyclodextrin. A preliminary investigation has been done to find out whether this enhancement of fluorescence can be used to develop a sensitive analytical method for determination of bromadialone in aqueous media. A linear relationship between the fluorescence intensity and concentration of bromadiolone was observed in the range of 0.15–7.9 μg ml⁻¹ in cetyltrimethylammonium bromide (CTAB) and 0.5–26.4 μg ml⁻¹ in β-cyclodextrin medium. The lower detection limit was found to be 37 ng ml⁻¹ in presence of CTAB and 23 ng ml⁻¹ in β-cyclodextrin. Comparison with 4-hydroxycoumarin, an unsubstituted analogue, was made.     

水杨基荧光酮光度法测定水中钛

本文研究了水杨基荧光酮光度法测定水中钛的实验方法,分析了表面活性剂溴代十六烷基三甲胺加入量对实验灵敏度影响,最佳显色时间,测定了地表水源地水中的钛。     

辽河东西支流与干流水体光学特性和组分对比研究

通过对东、西辽河和辽河干流有色溶解有机物(CDOM)吸收特性和荧光特征以及溶解有机碳(DOC)浓度的分析,对比研究不同子流域CDOM的光学特性差异,并分析影响CDOM与DOC浓度的主要因素.对比研究发现,辽河干流CDOM与DOC相关性(R = 0.89,P < 0.01)高于西辽河(R = 0.81)与东辽河(R = 0.75).总悬浮物浓度(TSM)和总碱度与不同子流域CDOM/DOC相关性较高.不同流域内CDOM与DOC的浓度变化较大,西辽河CDOM和DOC浓度明显高于东辽河和辽河干流.流域内土地利用、气候条件对两者浓度的影响显著,林地和CDOM及DOC浓度存在显著负相关(R = -0.41, -0.56),即林地面积越大,CDOM和DOC浓度越低;而农田与两者存在正相关(R = 0.40, 0.32),农田面积越大,相应的CDOM和DOC浓度越高;降雨量与CDOM和DOC呈现明显的负相关(R = -0.53, -0.38),说明降雨对河流CDOM的稀释作用较大.对于CDOM荧光强度Fn(355)与CDOM浓度来说,在每个子流域两者均存在较好的相关性,特别是西辽河流域(R = 0.96, P < 0.01).CDOM的三维荧光光谱发现,东、西辽河及辽河干流均表现出较强的类腐殖酸荧光峰(A峰和C峰),同时辽河干流表现出很强的类蛋白质峰(T峰).CDOM的吸收斜率(S)以及基于荧光光谱的FI和HIX表明东、西辽河和辽河干流CDOM的主要来源是外源高等植物输入的大分子量DOM,但是,西辽河和辽河干流CDOM的分子量要小于东辽河CDOM组成物质.     

差分吸收光谱法(DOAS)与紫外荧光法自动测量空气中SO2的对比

DOAS自动监测系统越来越广泛用于环境空气质量监测中SO2、NO2的监测,将差分吸收光谱法与紫外荧光法自动测量空气中SO2进行对比实验,并对监测结果进行讨论和统计检验,得出两种方法测定空气中的SO2,其监测结果具有较好的相关性、一致性、两者无显著性差异,在今后的监测工作中可用DOAS自动监测系统代替传统的干法点式自动监测系统监测SO2,以降低运行成本,减少仪器维护量,节约经费。     

Characterization of fulvic acids during olive mill waste composting (Elemental,Thermal and fluorescence analyses)

Elemental analysis, fluorescence spectroscopy and differential scanning calorimetry (DSC) were applied to the study of fulvic acids isolated from different stages during olive mill waste composting. The fulvic extracted acids are characterized by a high nitrogen content and O/C ratio values that may result from the high degree of humification and the synthesis of more condensed humic complexes. This was confirmed by fluorescence spectroscopy in the synchronous-scan mode by the decrease of shoulder intensities at intermediate wavelengths indicating the increase of polycondensation and conjugation of unsaturated structures and the greater uniformity of fluorophores. Fluorescence spectra in the emission, excitation and synchronous modes became simpler with compost maturation. This was confirmed by DSC results which proved the high degree of polycondensation of aromatic nuclei of fulvic acid molecules during olive mill waste composting.     

Valorization of agro-industrial fruit peel waste to fluorescent nanocarbon sensor: Ultrasensitive detection of potentially hazardous tropane alkaloid

• Transformation of agro-industrial waste to value-added material via green chemistry. • Orange peel is valorized into fluorescent nanodiamond-like carbon (fNDC) sensor. • fNDC detects potentially hazardous drug atropine sulfate (AS). • fNDC recognizes AS in biological fluids and pharmaceuticals. • fNDC assures applications in clinical and forensic toxicology. Millions of tonnes of agro-industrial waste are generated each year globally, with the vast majority of it going untreated, underutilized, and disposed of by burning or landfilling, causing severe environmental distress and economic downturn. A practical solution to this global issue is to use green chemistry to convert this waste into value-added products. Accordingly, in the present study, agro-industrial orange peel waste was valorized into fluorescent nanodiamond-like carbon sensor via a green route involving hydrothermal treatment of microwave carbonized orange peel waste. The developed sensor, used for the fluorescence detection of potentially hazardous drug atropine sulfate, exhibits unique dual linearity over concentration ranges of 300 nM to 1 M and from 1 M to 10 M, as well as ultra-low sensitivity of 34.42 nM and 356.46 nM, respectively. Additionally, the sensor demonstrates excellent reproducibility, high stability, and satisfactory recovery when used to identify and quantify atropine sulfate in biological samples and commercially available pharmaceuticals, indicating promising multidisciplinary applications.     

Binding of polycyclic aromatic hydrocarbons by humic acids formed during composting

Binding of two model polycyclic aromatic hydrocarbons (PAHs), phenanthrene and pyrene, by humic acids (HAs) isolated from an organic substrate at different stages of composting and a soil was investigated using a batch fluorescence quenching method and the modified Freundlich model. With respect to soil HA, the organic substrate HA fractions were characterized by larger binding affinities for both phenanthrene and pyrene. Further, isotherm deviation from linearity was larger for soil HA than for organic substrate HAs, indicating a larger heterogeneity of binding sites in the former. The composting process decreased the binding affinity and increased the heterogeneity of binding sites of HAs. The changes undergone by the HA fraction during composting may be expected to contribute to facilitate microbial accessibility to PAHs. The results obtained also suggest that bioremediation of PAH-contaminated soils with matured compost, rather than with fresh organic amendments, may result in faster and more effective cleanup.     

Numerical analysis of water and solute transport in variably-saturated fractured clayey till

This study numerically investigates the influence of initial water content and rain intensities on the preferential migration of two fluorescent tracers, Acid Yellow 7 (AY7) and Sulforhodamine B (SB), through variably-saturated fractured clayey till. The simulations are based on the numerical model HydroGeoSphere, which solves 3D variably-saturated flow and solute transport in discretely-fractured porous media. Using detailed knowledge of the matrix, fracture, and biopore properties, the numerical model is calibrated and validated against experimental high-resolution tracer images/data collected under dry and wet soil conditions and for three different rain events. The model could reproduce reasonably well the observed preferential migration of AY7 and SB through the fractured till, although it did not capture the exact depth of migration and the negligible impact of the dead-end biopores in a near-saturated matrix. A sensitivity analysis suggests fast flow mechanisms and dynamic surface coating in the biopores, and the presence of a plough pan in the till.     

荧光光谱法在环境监测中的应用

简要综述了荧光光谱在环境监测中近几年的应用。内容包括方法原理、方法的建立,有关荧光体系的研究,以及与其他技术的联用等一些最新进展。指出：荧光光谱法具有灵敏度高、选择性强、试样量少和测定简单等优点,为复杂环境样品中微量元素及痕量物质的分析提价了新手段,与其他手段结合使用,环境分析将具有更加广阔的前景,     

Analysis of the nitrifying bacterial community in BioCube sponge media using fluorescent in situ hybridization (FISH) and microelectrodes

There is growing interest in the development of more cost-effective and retrofit technologies for the upgrade and expansion of existing wastewater treatment plants with extreme space constraints. A free-floating sponge media (BioCube) process, using a 24L lab scale reactor, was operated to study the nitrification profiles and microbial community. The COD removal efficiencies were maintained, at an average of 95%, with the mixed liquor suspended solids (MLSS) inside the BioCube sponge media maintained at 12,688mg/L. The nitrification removal efficiencies were between 92% and 100%, with an average value of 99%. From the results of microelectrode measurements, the ammonium ion concentration was found to rapidly decrease from the surface of the BioCube sponge media to a depth of 2mm due to chemical reactions carried out by ammonia oxidizing bacteria (AOB) species. Multi-fluorescence in situ hybridization (FISH) has been used to investigate the spatial distributions of various microbial activities within reactors. Microbial communities were targeted using different oligonucleotide probes specific to AOB and nitrite oxidizing bacteria (NOB). There were a large number of AOB populations, but these were not uniformly distributed in the biofilm compared to the NOB populations.