饮用水中的痕量邻苯二甲酸酯类有毒物质检测

针对饮用水中增塑剂污染,结合当前的检测技术,提出一种基于色相谱的痕量邻苯二甲酸酯类有毒物质检测方法。对色相谱试验条件进行筛选,设定流动相主要为甲醇∶水=98∶2,温度为30℃,进样量为20μL/mg,流速为1 mL/min,DEHP检测波长为274 nm为最优色谱条件。试验结果表明,在测定的样品水样中,DEHP的浓度为0.016 mg/L,超出标准值,说明在区域的饮用水需加强增塑剂监测。     

HF-LPME-HPLC法测定水中4种邻苯二甲酸酯

研究建立一种中空纤维膜液相微萃取结合高效液相色谱(HF-LPME-HPLC)测定水中4种邻苯二甲酸酯(PAEs)的方法。考查了中空纤维膜的长度等参数对萃取效果的影响。结果表明,中空纤维膜长度为8 cm,1-丁基-3-甲基咪唑六氟磷酸盐([BMIm]PF6)为萃取剂,十二醇为支撑膜相,萃取时间为5 min时,萃取效果最好。该法中4种PAEs的线性范围为10~1 000 ng/m L(R2均大于0.999),检出限为1.67~7.38 ng/m L,相对标准偏差(RSD)为2.1%~5.7%(n=5)。实际样品测定中,加标回收率为89%~107%,因此,该法可用于水样中4种PAEs的测定。     

湘江水中邻苯二甲酸酯类环境激素的研究

采用分散液液微萃取-高效液相色谱法测定湘江株洲段水体中邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二正丁酯(DBP)和邻苯二甲酸丁苄酯(BBP),利用正交实验优化了萃取条件,分析其污染水平分布,并进行生态风险评价。结果表明:4种邻苯二甲酸酯类物质普遍检出,∑PAEs的浓度范围为22.39～27.4μg/L,其中DBP为主要污染物。利用商值法对PAEs进行生态风险评价,各种物质均存在潜在生态风险。     

饮用水中邻苯二甲酸酯的调查及去除研究

采用固相萃取-高效液相色谱法调查了淮南市某自来水厂原水、各处理工艺单元出水中4种邻苯二甲酸酯(DMP、DEP、DBP、BBP)。结果表明,4种邻苯二甲酸酯在原水中均检出,质量浓度为0.010～0.142μg/L;DMP和DEP仅在部分水样中检出,在管网水中没有检出;DBP和BBP在各水样中均检出,质量浓度分别为1.702～2.897μg/L、0.248～0.676μg/L,说明现行常规净水处理工艺不能完全去除邻苯二甲酸酯,需要进行深度处理。研究采用臭氧氧化技术、活性炭吸附技术和臭氧-活性炭技术对该水厂原水中的2种邻苯二甲酸酯(DBP、BBP)去除情况进行验证。结果表明,臭氧氧化技术不能完全去除原水中的DBP和BBP,去除率为61%～65%;活性炭吸附技术能够完全去除原水中的DBP和BBP;臭氧-活性炭技术对原水中的DBP和BBP去除率达到100%。该技术可以作为水厂深度处理工艺去除DBP和BBP的主要单元。     

纳滤膜去除水中微量邻苯二甲酸酯的研究

邻苯二甲酸酯（PAEs）是一类环境雌激素,对人体健康造成严重危害。本研究运用纳滤膜处理水中微量PAEs,以最常用的邻苯二甲酸二乙酯（DEP）,邻苯二甲酸二丁酯（DBP）,邻苯二甲酸二环己酯（DCHP）,邻苯二甲酸二异辛酯（DEHP）为研究对象,研究压力、原水浓度、离子强度、和pH值等因素对其截留行为的影响。结果表明：纳滤技术是去除水中微量PAEs的有效方法,平均截留率在90%以上;纳滤过程中,截留率随物质分子量的增加而增加;影响膜性能的主要的因素是操作压力、离子强度和pH值,原液浓度对膜性能影响不大;最佳去除条件为：压力0.4MPa,pH=7,电导率为0.2μS/cm。     

邻苯二甲酸酯类增塑剂的检测标准现状分析

简要介绍了邻苯二甲酸醋类增塑剂的应用现状,对国内外邻苯二甲酸醋类增塑剂检测标准进行了分类和比较,客观分析了标准现状和存在的问题,并提出了对策.     

水源水中邻苯二甲酸酯内分泌干扰物的去除进展

近年来,新兴环境激素污染物邻苯二甲酸酯(PAEs)在水源水中被频繁检出,对人类饮用水健康产生潜在威胁,而我国目前城市给水处理的常规工艺流程对PAEs的去除效果甚微,发现及推广高效稳定的PAEs去除技术对保障饮用水安全至关重要。文章总结比较了水源水中PAEs的最新去除方法,并对未来水源水中PAEs处理的发展方向进行展望。     

水体中邻苯二甲酸酯类化合物分析检测方法研究进展

邻苯二甲酸酯(PAEs)是一类广泛使用的化学品,主要作为增塑剂用于塑料制品生产中。PAEs容易从塑料中迁移到外环境,造成对环境的污染,经研究表明其对人体和生物体具有较大的毒性,引起了广泛关注,因此对于PAEs的研究检测显得十分重要。本文综述了近几年来对水体中邻苯二甲酸酯类化合物的前处理方法和分析检测技术的研究情况,并探讨了分析方法的研究方向。     

污泥中邻苯二甲酸酯生物降解性与化学结构的相关性

为预测邻苯二甲酸酯类环境激素的好氧生物降解性,评价其在城市污泥中的滞留情况,应用定量结构-活性关系(QSAR)研究方法,对城市污泥中邻苯二甲酸酯类化合物的好氧生物降解性能与其化学结构间的关系(QSBR)进行了研究。研究表明,污泥中邻苯二甲酸酯类化合物好氧生物降解速率常数随受试物相对分子质量的增大而减少,以分子连接性指数描述的空间结构参数是影响受试物好氧生物降解性能的重要因素。     

Thermal stability of phthalic esters

Phthalic esters, as typical plasticizers for vinyl plastics, were thermally decomposed by a flow reactor system and their decomposition products were analyzed in detail. The thermal decomposition products were olefin, alcohol, hydrogen phthalate, benzoates with alkyl groups corresponding to these of the original phthalate esters and phthalic anhydride. We found from the main thermal decomposotion products-olefin, alcohol and hydrogen phthalate-that phthalic esters were thermally decomposed throughcis-elimination in the same way as in the general case for esters. In the presence of polyvinyl chloride (PVC), hydrochlorinated products were identified in the decomposition products. A good relationship was found between the amount of chloroalkanes produced and the reaction temperature. Thecis-elimination reaction of phthalic esters was found to be promoted by PVC.     

Anomalous viscosity behavior of fatty acid esters in solution

Solution viscosity of oils of melonseed(Colocynthis vulgaris Schrad.), soyabean [Glycine max (L). Merr], and rubberseed [Hevea brasiliensis (Kunth) Muell.] were determined in different solvents at various concentrations. Reduced viscosity(_{η red}) vs concentration (C) plots showed three types of behavior:_{η red} increased linearly with C (2–30 g/dl);_{η red} levelled off with C (2–1.2 g/dl); and_{η red} rose steeply with decrease in C (below 1.2 g/dl), the latter behavior is anomalous. Similar viscosity behavior was observed for the methyl ester of melonseed oil, methyl palmitate and n-butyl acetate. Molecular cluster formation was believed to cause the observed anomalous viscosity behavior, the extent of which varied, depending on the nature of the fatty acid ester and the solvent.     

Sonophotocatalytic degradation of trichloroacetic acid in aqueous solution

The degradation of trichloroacetic acid (TCA) in water under ultrasound (US), ultraviolet (UV)/TiO₂, and combination of UV/TiO₂ and US irradiation was investigated. It was found that the extent of sonophotocatalytic degradation was higher compared with sonolysis or photolysis alone. The influence of operating parameters such as TiO₂ concentration, pH values, temperature and dissolved gases on sonophotocatalytic degradation of TCA was studied. Enhancement in the degradation rate has been observed at a higher catalyst loading, a higher temperature and an acidic condition under dissolved oxygen. In addition, the degradation kinetics, mechanism and possible degradation products were discussed in detail.     

The oxidation of valeric acid in aqueous solution

The liquid phase oxidation of an aqueous solution of a lower fatty acid, valeric (pentanoic) acid, has been studied at high temperatures (240?325°C) and pressures (10.3-10.4 MPa) in a batch autoclave reactor. The objective of the study was to develop a mechanistic understanding of the wet oxidation of industrial wastewaters contaminated with vegetable oils. Valeric acid was chosen as the prototype molecule. High performance liquid chromatography (HPLC) has been used to identify the liquid products and estimate their concentrations as a function of the extent of oxidation. Moreover the technique of GC-MS has also been used to obtain information on specific intermediate oxidation products that could not be identified by HPLC. The gaseous products of the reaction have been also identified and quantified. A detailed reaction mechanism is proposed based on free radical reactions.     

Autoxidation of cholesterol fatty acid esters in solid state and aqueous dispersion

Cholesteryl stearate, oleate, linoleate, linolenate and arachidonate were oxidized in solid form (at 100 C) and in a water dispersion (in the presence of potassium stearate, pH 7.5, 80 C). The unsaponifiable fraction was analyzed by capillary gas liquid chromatography. In the solid state, the oxidation rates of esterified cholesterol were high for stearate and oleate, low for the polyunsaturated esters and very low for free cholesterol. In water dispersion, the rates were reversed, e.g., free cholesterol oxidized more quickly than its stearic and oleic acid esters. The fatty chains in 18∶0 and 18∶1 inhibited the autoxidation of cholesterol. Hydroxylation of the cholesterol side chain only occurred during solid-state autoxidation as previously observed by others. The 20- and 25-hydroxycholesterols were never detected in the products of micellar reactions, regardless of which surfactant was used for micelle formation.     

电化学合成邻苯二甲酸和邻甲苯酸

以邻二氯苯、邻氯甲苯、二氧化碳为原料,N,N-二甲基甲酰胺为溶剂,铝、镍网及化学镀镍膜为阳极,不锈钢网为阴极,牺牲阳极法制备邻苯二甲酸、邻甲苯甲酸,邻苯二甲酸的产率为16%,电流效率为48%。     

Conformational behavior of N-acylamino acid oil and N-acylamino acid surfactant in aqueous solution

The (13)C- and (1)H- NMR spectra of isopropyl N-dodecanoylsarcosinate (SLIP) were measured in CDCl(3), CD(3)OD and in sodium dodecanoylsarcosinate (Sar) aqueous solution. The existence of both cis and trans isomeric forms are observed for SLIP just as for Sar. The trans/cis ratio of SLIP in a dilute CDCl(3) solution is over 3.2, which is indicating that SLIP-trans conformation is more stable in an organic solvent. However, the population of SLIP-trans isomer decreases in aqueous solutions. This may be explained by the interaction of the ester group and N-acyl chain. Addition of SLIP to the water/Sar solution causes the conformational change of both SLIP and Sar. With increasing SLIP concentration, the population of SLIP-trans isomer increases and Sar-cis isomer, which is known to be preferred in the monomer state, also increases. This phenomenon is discussed in the context of the phase transition behavior of SLIP/Sar/water system. At high SLIP and Sar concentration, broadening of (1)H signal relative to 2-CH(2) of Sar occurs both for trans and cis forms, however, broadening of that of Sar N-CH(2) and N-CH(3) is observed only for trans. Analysis of conformation change by NMR was proved to be useful method for phase behavior analysis of an acylamino acid surfactant.     

Specific susceptibility of docosahexaenoic acid and eicosapentaenoic acid to peroxidation in aqueous solution

The peroxidation of different polyunsaturated fatty acids (PUFA) after photoirradiation in aqueous solution was evaluated by measuring fatty acid loss and malonaldehyde production in medium. The oxidation rates of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two highly unsaturated fatty acids of the n−3 series, were surprisingly lower (14 and 22%, respectively) than the oxidation rates of linoleic, α-linolenic, γ-linolenic, dihomo γ-linolenic, and arachidonic acids (62–90%). The quantities of malonaldehyde (MA) produced were assayed simultaneously by gas chromatography (GC) and high performance liquid chromatography (HPLC). MA production was found to be related to both the degree of unsaturation and the metabolic series of the fatty acid. The maximum value was observed with arachidonic acid (MA production from 2 mM arachidonic acid in aqueous solution was estimated at 44.9±6.0 μM by GC and 46.8 ±4.0 μM by HPLC). Eicosapentaenoic acid and docosahexaenoic acid produced lower MA quantities compared to arachidonic acid (MA production from 2 mM EPA and 2 mM DHA was estimated at 17.9±1.5 μM and 37.9±0.7 μM, respectively, by GC, and 26.3±4.9 μM and 37.3±4.2 μM, respectively, by HPLC). The MA yield, defined as the amount of MA (nmols) produced per 100 nanomoles of oxidized fatty acid, was used to express the susceptibility of individual PUFA to peroxidation. The MA yield correlated well with the degree of unsaturation, but was independent of carbon chain length and metabolic series. The study suggests that adequate assessment of lipid peroxidation cannot be achieved by measuring MA formation alone, but it also requires knowledge of the fatty acid composition of the system studied.