Liquid chromatography with diode array detection and multivariate curve resolution for the selective and sensitive quantification of estrogens in natural waters

Following the green analytical chemistry principles, an efficient strategy involving second-order data provided by liquid chromatography (LC) with diode array detection (DAD) was applied for the simultaneous determination of estriol, 17β-estradiol, 17α-ethinylestradiol and estrone in natural water samples. After a simple pre-concentration step, LC–DAD matrix data were rapidly obtained (in less than 5 min) with a chromatographic system operating isocratically. Applying a second-order calibration algorithm based on multivariate curve resolution with alternating least-squares (MCR-ALS), successful resolution was achieved in the presence of sample constituents that strongly coelute with the analytes. The flexibility of this multivariate model allowed the quantification of the four estrogens in tap, mineral, underground and river water samples. Limits of detection in the range between 3 and 13 ng L⁻¹, and relative prediction errors from 2 to 11% were achieved.     

Application of factorial design to study of heavy metals biosorption by waste biomass from beverage distillery

A full factorial design leading to 20 sets of sorption runs was conducted to study the influence of four variables (bleaching earth and biomass concentrations, pH, and sorption time) on the iron, nickel, and chromium removal from stainless steel effluent using waste biomass from a beverage industry. Similar factor effects and interactions were found for each metalinvolved in this biosorption study, and the main factors were pH (positive effect) and biomass concentration (negative effect). Response surface methodology was adopted and an empirical linear polynomial model constructed on the basis of the specific uptake (mg of metal/g of biomass as dry weight) for each metal species. Under optimized process conditions (pH 4.0, biomass concentration of 2.0 g/L, absence of Celite), uptake values of 155 mg of Fe/g, 38 mg of Cr/g, and 0.4 mg of Ni/g were achieved after 3 h. This corresponded to a reduction in heavy metals concentration of approx 94% for Cr, 57% for Fe, and 25% for Ni.     

一种处理含Cr3+电镀污水的新工艺

介绍了电生物膜方法治理重金属离子有机废水的基本原理，采用自主研究并开发的新型电生物膜偶合工艺处理了含Cr^3 的电镀厂排污废水，通过长期连续实验研究了微生物生长代谢的营养源以及生物膜脱落更新下的废水净化效果。实验结果表明，电生物膜法对含Cr^3 的电镀废水水质水量波动适应性强，含Cr^3 初始浓度为5～80mg/L的电镀废水均可得到高效治理，出水浓度为1．0mg/L左右，低于工业污水排放标准。同时，得到了操作电压、废水pH、停留时间、温度等的最佳工艺条件调节方法和规律。实验还表明，生物膜成长后期的脱落更新能够保证连续高效净化重金属离子有机废水。     

印染废水处理厂排水中有机物的荧光方法表征

我国苏南地区印染企业众多,废水排放量巨大,加强印染废水的处理排放管理势在必行。三维荧光光谱测量快速、灵敏,能够反映水中有机物组成,可以弥补化学需氧量等传统有机物指标评价水质的不足。采集了我国苏南某市5家运行良好、达标排放的印染废水处理厂的排水,进行了总有机碳、UV254和三维荧光光谱的测定,来表征其中的溶解性有机物。5家污水处理厂排水的单位总有机碳的UV254为1.42~4.29L·mg~(-1)·m~(-1),表明其有机物芳香化水平与城市污水处理排水接近。各个污水处理厂印染废水处理排水的三维荧光光谱有所差别,但主要都有两个荧光峰,其激发波长和发射波长分别位于230/340和275/320nm处,校正归一化后的荧光强度远高于城市污水处理排水,而腐殖化指数远低于城市污水处理排水,表明印染废水处理排水相比城市污水处理排水存在较大比例的非腐殖类芳香族化合物。通过测定周边印染企业常用染料的三维荧光光谱可以推测印染废水处理排水的荧光信号可能来自于残留的染料及其未完全降解的中间产物,可能会对水环境造成一定的危害。研究显示三维荧光光谱在显示水体有机物污染组成上具有一定优势。     

污水厂出水颗粒态与溶解态有机物的红外和荧光光谱特征

城市污水处理厂出水作为再生水的主要水源,其迥异的物质组成给受纳水体带来潜在环境风险。全面掌握污水厂出水水体中有机物组成及结构信息,将为污水厂提标改造及有毒有害物质排放标准的制定提供理论支撑。采用傅里叶变换红外光谱和三维荧光光谱技术,结合二阶导数光谱及区域积分分析方法,对4个典型城镇污水处理厂(W1,W2,W3,W4)出水水体中颗粒态有机物(POM)与溶解态有机物(DOM)的物质组成及结构差异特征进行了分析。结果显示： 污水处理厂出水中POM主要组分为脂肪类、芳香类、糖类及矿物盐,而DOM主要由有机酸、蛋白质、多肽、糖类及芳香类物质组成。各污水处理厂出水水体POM中,W1芳香类物质较多而矿物盐类等颗粒较少,W2较W1含有更多的糖类物质,W3含较多脂类、蛋白类及糖类,而W4含有芳香类及羧酸物质的有机物较多。水体DOM组成中,W1和W2成分较为类似,主要为芳香性较高的大分子有机酸,其含量分别占总有机物的73.9%和67.7%;W3与W4组成中蛋白、多肽及糖类含量较高,其中类蛋白物质分别占DOM总量的71.3%和53.5%。研究结果表明,采用傅里叶变换红外光谱结合二阶导数分析能很好识别不同污水处理厂出水水体中POM与DOM主要物质组成及结构差异,同时利用区域积分方法对样品三维荧光光谱进行解析,能更进一步定量分析不同来源样品物质组成特征。     

Preparative gas chromatography with glass capillary columns

The present paper describes an automated system for preparative gas chromatography with glass capillary columns, controlled by a microprocessor. The effluent from the capillary column is divided by a pneumatically controlled splitter and any desired split ratio between traps and detector can be obtained. Moreover, a second pneumatic control allows instantaneous change-over to a different split ratio, thus minimizing loss of material during collection. The effluent containing the compounds of interest is passed through a multiple manifold and collected in coiled glass capillary traps. To ensure maximum trapping efficiency even for very small amounts of material, the inner walls of the capillary traps are wetted with a suitable solvent, which gives a quantitative recovery of micro- and nanogram amounts of material. After repetitive sampling, sufficient amounts of material can be obtained for NMR spectroscopy and possibilities exist to enrich trace components with the aid of a double column system. Two examples of such applications are given, employing mixtures of both synthetic and natural origin.     

Practical aspects of Pt/Ir effluent splitters for multidetector GC and pneumatic solute switching

Practical details are given to produce low dead volume Pt/Ir to glass connections and a variety of components for effluent splitting and pneumatic solute switching. It is shown that the column effluents from a glass capillary column can be split in any desired ratio and maintained constant, regardless of column flow rate. Bandbroadening in the splitter remains negligible even for very low flow rates. A complex pneumatic system to be used for heartcutting with two glass capillary columns is shown.