Some applications of Freon-22 in supercritical fluid chromatographic analysis of environmental pollutants

The applications of Freon-22 (R22) as a mobile phase and as a modifier in supercritical fluid chromatography were investigated. For the purpose of this investigation, the separation of eleven phenols listed by the United States Environmental Protection Agency as priority pollutants was studied. It was found that the use of neat R22 greatly reduced the retention times of the phenols compared with the use of neat carbon dioxide as mobile phase. Satisfactory separation of all the eleven phenols could be achieved using 5% R22 as modifier in carbon dioxide. The promising results obtained in this preliminary investigation indicate the potential for the use of R22 in supercritical fluid separation processes.     

Separation of selected PAHs by using high performance capillary electrophoresis with modifiers

The effect of varying SDS concentration in a micellar electrokinetic capillary chromatographic system (MECC) is investigated. In addition, the introduction of -cyclodextrin as modifier to the electrophoretic medium, containing SDS and a phosphate-borate buffer, is shown to give satisfactory separation of the seven selected PAHs. The separation efficiency is increased with the addition of -cyclodextrin.     

Investigation of the use of honey bees and honey bee products to assess heavy metals contamination

Forty-four water samples from eleven sampling points were collected from four highly polluted rivers of northern India once in each four seasons during 1988–1989. The samples were analyzed for phenol, chlorophenols, a few bromophenols and other organics. Phenol was found to be absent in all the analyzed samples. Trichlorophenol and pentachlorophenol were frequently detected. Comparatively, the Ganges river was most polluted at Kannauj followed by Narora, Kachala and Fatehgarh. Maximum phenols were found at Mathura downstream of the Yamuna river followed by Mathura upstream, Okhla, ITO and none at Wazirabad. No phenols were detected in the water of the rivers Hindon and Kali at Ghaziabad and Aligarh, respectively. Some other organic pollutants were also identified by their mass spectra and supported by data from the computerized library, but, not quantified.To whom correspondence should be addressed.     

固相萃取-高效液相色谱法测定废水中的酚类化合物

建立了Supelclean ENVI-Chrom P柱固相萃取-高效液相色谱法测定废水中11种酚类化合物的分析方法,并对固相萃取条件和液相色谱条件进行了讨论。该方法分离效果良好,净化效果明显,方法检出限为2×10-3~2×10-2mg/L,平行分析(n=6)的RSD为2.7%~16.4%,废水加标回收率除2,4-二硝基酚偏低以外,其他化合物的回收率为61.4%~115.8%。     

An optimization procedure for the isocratic high-performance liquid chromatographic separations of environmental pollutants

This paper describes the use of the overlapping resolution mapping procedure to optimize the separation of priority pollutants by isocratic, reversed-phase high-performance liquid chromatography. Three classes of pollutants are considered: polycyclic aromatic hydrocarbons, substituted phenols and phthalate esters. The procedure requires only seven chromatographic runs for each set of pollutants before an optimized mobile phase composition is derived which can satisfactorily resolve all the components in the respective mixtures of pollutants. The main advantage of such a systematic scheme to optimize mobile phase compositions is an improvement in method development times compared to conventional techniques. Another benefit is that expenditures on solvents are reduced.     

水中多种酚类化合物同步提取方法研究

对水中14种酚类化合物的液液萃取过程进行研究,选取不同萃取溶剂体系、水样pH和盐析条件等多个对萃取效率有决定性影响的参数进行优化。通过上述条件的优化选择,实现了同步对包括低沸点的苯酚、一氯代酚及较难提取的甲基酚和硝基酚等14种不同类型酚类化合物最优的萃取,提取效率达到75.2%~110.3%。     

底质中石油和酚类浸溶试验

研究小东江水闸至斜岭全程１０Ｋｍ河段底质中石油和酚类污染物含量的沿程分布,并对底质进行浸溶试验,结果表明,该河段底质中石油平均含量为２７．５８ｍｇ／ｋｇ,酚类为０．０９８ｍｇ／ｋｇ,石油平均浸出率为３５％,酚类平均浸出率为４９％,在一定的条件下,可能导致水体的二次污染。     

Multi-component analysis of polar water pollutants using sequential solid-phase extraction followed by LC-ESI-MS

A multi-component screening analysis method for polar to medium-polar water pollutants was developed. Sample clean-up and group separation are performed by sequential solid-phase extraction (SSPE) using automated SPE with C18 and polymeric sorbent materials. Analyses are performed by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) using a single-quadrupole instrument. More than 90 priority compounds of environmental interest--comprising the most important chemical and substance classes: phenols, carboxylic acids, aromatic sulfonates, aromatic amines, pharmaceuticals, surfactants, dyes, and pesticides--have been chosen for the experiments. The compounds are divided by the SSPE procedure into 3 different polarity classes. The extraction recoveries were determined in the 3 fractions for every single substance, and were for most of the analytes in the range of 50-100%. A mixture of hexane-dichloromethane was used for the elution of nonpolar compounds like alkylphenols from C18. Methanol and acetone are well suited for the elution of more polar substances. The limits of detection (LODs) were determined for all compounds. Effluents from municipal and industrial wastewater treatment plants (WWTPs) treating waste water from textile industries; and the corresponding receiving waters (rivers and lakes) have been analysed with the developed method. Urban and industrial pollution was observed in rivers and streams in the area north of Milan, Italy. In the water samples different phenols (nitrophenols, bisphenol A, nonylphenol), alkylphenol ethoxylate surfactants, their metabolites with endocrine disrupting potential, aromatic sulfonates, linear alkylbenzenesulfonate surfactants, dyes, pesticides, pharmaceuticals, and a dichlorobenzidine compound were identified.     

大同市地表水及工业废水中氯苯和酚类化合物的监测

对流经大同市的主要河流和重点工业污染源所排放废水中的氯苯和酚类化合物做了分析测定.对酚类化合物的测定方法进行了改进.研究表明,大同市污染源对御河氯苯类污染物贡献较小,焦化厂酚类化合物排放量较高.     

固定化多酚氧化酶测酚电极的研究

用从马铃薯中提纯,经吸附交联得到的固定化多酚氧化酶与氧电极组装设计而成的酚传感器,可检测大多数酚类化合物,其灵敏度、准确度、线性范围、响应速度、稳定性及抗干扰性,均可基本满足要求。研究证明,该法具有一定的开发实用价值。     

挥发酚在废水中的特性和分布规律研究

主要通过对废水中挥发酚的特性和时空分布规律研究，找到最能代表其废水水质的采样点位     

垃圾填埋场地下水污染对居民健康的风险评价

调查了某垃圾填埋场地下水和周边居民饮用水中的As、Hg等重金属和挥发酚等有机物的污染状况，运用美国环保局的健康风险计算模型，评估了该垃圾填埋场地下水对周边居民的潜在健康风险。结果表明，各类人群对4种有阈化合物的饮食和皮肤暴露的终身健康危险度在8．2×10^-11～1．3×10^-10之间，均低于可以接受的风险水平10^-6；对As的终身超额健康危险度在3．1×10^-7～4．9×10^-7之间，表明地下水中砷污染对居民潜在的致癌风险不明显。各类人群通过皮肤对Hg、As、Cd和挥发酚的暴露剂量比通过饮水暴露的剂量高0．7倍～14．5倍，皮肤暴露将是地下水影响人体健康并构成潜在风险的重要途径。     

萃取光度法测定高浓度挥发酚初步探讨

用氯仿多次萃取高浓度挥发酚，可提高试样中待测组分的萃取率，其测定结果准确度令人满意。     

Bioluminescent enzymatic rapid assay of water integral toxicity

A bioluminescent rapid method was developed to estimate the integral toxicity of natural and wastewater. This method is based on registering the effect of the polluted water sample on the parameters of the bioluminescent reaction catalyzed by the multi-component reagent containing NADH:FMN oxidoreductase, luciferase, and their substrates co-immobilized in a starch carrier. Several ways to increase the method's sensitivity to toxic substances were suggested; conditions were selected to make it possible to determine, with maximum efficiency, the content of toxic substances corresponding to a certain maximum permissible concentration. The sensitivity of soluble and immobilized coupled enzymatic systems to a series of organic pollutants (phenols, quinones, and salts of heavy metals) was compared. It was shown that the reagent is the most sensitive to the effect of phenols and quinones. The method was tested during analysis of the wastewater from a pulp and paper plant and can be used for biotesting in both laboratory and field conditions.     

乙腈盐析萃取HPLC-PDA同时测定水中11种苯胺类化合物

通过对色谱分析和样品萃取条件的选择和优化，建立了同时分析水中11种苯胺类化合物的HPLC方法。样品经乙腈盐析萃取后直接进样分析，采用 ODS色谱柱，以乙腈-水为流动相进行梯度洗脱，用PDA检测。结果表明，11种苯胺类化合物在0.20~100mg/L范围内其浓度和检测信号呈良好的线性关系，方法检出限为0.002~0.007mg/L，地表水和废水样品加标回收率为81.6%~97.4%，相对标准偏差为1.5%~5.5%。     

环境水质中酚类优先监测物的分析方法

介绍测定环境水质中酚类优先监测物质的分析方法，并对各种分析方法进行了对比分析，最后指出固相微量萃取法（ＳＰＭＥ）所具有的优点     

Removal of phenols and other pollutants from different landfill leachates using powdered activated carbon supplemented SBR technology

In this research, two types of sequencing batch reactors (SBRs) with 8 h of cycle times, namely non-powdered activated carbon (NPAC-SBR) and powdered activated carbon (PAC-SBR), were used for the treatment of raw leachates at Kulim and Pulau Burung landfill sites. To test the performance of SBRs, phenols, total iron, zinc, ammonia, nitrite, nitrate, color, suspended solids, chemical oxygen demand, biochemical oxygen demand, and total dissolved salts removal efficiencies and sludge volume index (SVI) were studied at both sites. The rates of phenols removal, for instance in NPAC-SBRs and PAC-SBRs at Kulim, were 25% and 55%, respectively, whereas those at Pulau Buring were 94.81% and 97.75%, respectively. PAC as adsorbent in PAC-SBRs enhanced the removal efficiencies of the aforementioned pollutants from leachates at both sites. In addition, PAC as adsorbent decreased the SVI values at Kulim (59.7 mL/g) and Pulau Burung (91.4 mL/g) leachates and improved the nitrification and denitrification processes.     

Detection of chlorophenolics in effluents from bleaching processes of rice-straw pulp

A number of chlorinated derivatives of phenols, catechols, guaiacols, syringaldehydes, have been detected and their concentrations estimated, using gas chromatography in the chlorination (C) and extraction (E) stage of spent bleach liquor generated in the laboratory by bleaching rice-straw soda pulp. The concentration of various compounds detected have also been compared with their reported 96LC50 values.     

西夫(Schiff)碱侧链聚硅氧烷毛细管柱气相色谱固定相的制备与色谱性能

将合成的西夫 (Schiff)碱侧链聚硅氧烷高分子液晶化合物用作毛细管柱气相色谱固定相 ,具有较高的柱效 ,热稳定性较好 ,最高柱温可达 2 80℃ ,对苯的各种取代物、酚类及多环芳烃有良好的选择性 ,尤其对位置异构体有独特的分离效果。     

Phenolic water pollutants in a Malaysian River basin

Phenolic chemicals with their very low taste and odour thresholds, high persistence and toxicity, are of growing concern as water pollutants. The compounds are known to exist in raw water as well as in treated water. The level of phenolic priority pollutants in water within the catchment area of the Linggi River Treatment Plant in Negeri Sembilan, Malaysia, which includes the Linggi river basin, was monitored. The 4-aminoantipyrin colourimetric method was used to determine total phenols whereas capillary column gas chromatography was used to determine the individual compounds. The results show that at most sampling stations, particularly those within the Seremban municipality, the level of phenols was found to exceed the recommended Malaysian standard of 2.0 g/L^-1 for raw water. This is seen as the direct impact of industrial and urbanization of the area and clearly indicates the unhealthy state of the Linggi river. The results also indicate the need to improve the water quality if the river is going to be used as a source of raw water.