流动注射分析在环境水质重金属检测中的应用进展

重金属具有毒性大、不易被代谢、易被生物富集并有生物放大效应等特点,不但污染水环境,也严重威胁人类和水生生物的存在。近年来各类水环境中重金属污染日趋加剧,重金属的检测及处理方法有多种,而流动注射分析技术以其自动化程度高、分析速度快、精密度高、分析成本低等优点在水环境监测方面占有重要地位。介绍了流动注射在重金属检测方面的应用。     

含羟肟酸侧基高分子重金属捕集剂处理含铅废水的研究

铅是有毒的重金属,其污染主要来源于颜料、铅蓄电池、矿冶、电镀及印刷电路版制作等作业.铅在人和动植物中具有蓄积稳定性,进入人体后很难排除;停留体内对人的中枢神经系统和骨骼造成伤害,早已引起医学界重视,被列为严格控制排放的第一类污染物.     

化学钝化法修复重金属污染土壤研究进展

化学钝化修复是通过往土壤中加入钝化剂,以调节和改变重金属在土壤中的物理化学性质,使其发生氧化还原、沉淀、吸附、螯合、抑制或拮抗等一系列反应,降低其在土壤环境中的生物有效性和可迁移性,从而减少这些重金属元素对动植物的毒性.这种方法因投入低、效率高、修复快速、操作简单等优点,对大面积污染土壤的修复具有较好的应用前景.文中系统地综述了土壤重金属污染现状、危害、来源、特点及化学钝化修复技术的类型、作用机理、影响因素、修复实例,并分析了化学钝化技术的研究现状、存在的问题及未来的发展方向.     

硒对汞毒性的拮抗作用及机理

硒是一种生物必需微量元素,而汞是剧毒重金属元素之一.硒、汞相互作用一直备受国内外研究者关注.本文系统概括了人体、动植物及生态系统中硒、汞相互作用的研究进展,探讨了硒、汞相互作用的机制,以期为利用硒降低汞的毒性提供理论基础,为降低汞对人体及环境健康的危害和国家汞污染治理提供技术支持.     

重金属Cd2+对细胞外向K+通道的影响

重金属镉(Cd)污染及其对动植物的伤害机理,已成为中外相关专家研究的热点,但是细胞毒害机理依然不清楚.分布于细胞膜上的通道蛋白,不仅是外来物质作用于生物体的首要位点,且会影响离子通道的功能.为阐释镉(Cd)污染致病与毒害的细胞学机理,选择具有重要生理功能的细胞钾离子(K+)通道为示踪,并应用全细胞膜片钳技术,研究了Cd...     

某冶炼厂周边土壤重金属污染评价分析及源解析研究

有色金属矿产资源采选冶活动造成的土壤重金属污染已成为严重的环境问题。采用电感耦合等离子体质谱法和光谱法测定某冶炼厂周边不同区域内土壤中重金属Cu、Pb、Zn、As、Ni、Cr、Cd、Hg元素含量,采用Kriging空间插值方法对重金属空间分布特征进行分析,采用内梅罗指数法对其污染状况进行评价,采用多元统计分析对重金属元素的污染源进行分析。结果表明,研究区土壤采样点80%处于污染状态,且以重度污染为主,污染比较严重的区域受风向影响在冶炼厂的西部和南部方向,污染严重的重金属元素为Cu、Pb、Cd、Zn和As,土壤中各重金属元素的污染源除来自于冶炼厂外,Zn-Cd-PbCu-As、Ni-Cr、Hg分别还受到机动车辆排放、自然因素、燃煤及农药使用的影响。     

地积累指数法及生态危害指数评价法在土壤重金属污染中的应用及探讨

将近年常用于重金属污染的地积累指数法及生态危害指数评价法进行了对比分析,并对西南某铅锌矿矿区表层土壤中重金属(Zn、Pb、Cd、Cu)污染情况进行了评价。结果表明,该区Cd为极严重污染,Pb为中等污染,Zn和Cu为轻微污染。地积累指数评价法和生态危害指数评价法两者各有侧重点,对于重金属污染的系统评价各具合理性;但两种方法都是基于沉积学理论提出,在对土壤重金属污染进行评价时,有其局限性,建议在对其参数修正后综合应用。     

黑苦荞保健茶中重金属的分析评价

采用原子吸收光谱法和原子荧光光度法测定了四川省凉山州某几个品牌黑苦荞保健茶中的重金属铅、镉、铬、无机砷和汞的含量,并以NY/T 1510-2007标准绿色食品麦类制品为依据,对黑苦荞保健茶重金属污染状况进行了分析评价。结果表明,黑苦荞保健茶受重金属元素污染的程度由高到低表现为铅、铬、镉、无机砷和汞,但含量均未超过国家标准规定;黑苦荞叶芽茶和全株茶的重金属污染较为严重,全胚茶未受重金属污染。     

微波辅助-液液微提取环境水样中的三嗪类除草剂

三嗪类除草剂作为农田杂草生长的抑制性农药在世界范围内广泛使用.这类农药对土壤、地表径流、地下水造成污染,并对人类、动植物和水生生物造成不利影响.因此,控制水中农药浓度至关重要.目前,除草剂残留的检测方法主要有气相色谱法(GC)、气相色谱-质谱法(GC-MS)、高效液相色谱法(HPLC)~([1])、离子色谱法等~([2,3]).本实验以离子液体为提取剂,微波辅助-液液微提取法测定环境水样中三嗪类除草剂.     

成都平原典型地区水果-土壤重金属污染特征研究

为摸清成都平原土壤-水果系统中重金属污染水平和富集特征,通过对成都平原典型地区333个水果作物及其根部表层土壤中Hg、As、Pb、Cd、Cu、Cr和土壤理化指标的测定,结果表明：（1）研究区土壤养分整体呈现出有效磷和碱解氮较丰富,有机质和速效钾较缺乏的特征,可通过增施有机肥、地面覆草、施用绿肥等方式提升土壤肥力水平。（2）研究区土壤重金属存在部分点位超标,以Cd的超标率最高。土壤重金属单因子评价污染等级为清洁,土壤综合污染指数评价污染等级为中度污染,其主要贡献为Cd。研究区重金属存在一定程度的富集,Cd和Hg的污染指数高,潜在生态风险强,应重点关注土壤Cd污染和Hg含量水平的增加趋势,将Cd污染作为下一步土壤风险管控和修复治理的重点目标。（3）研究区水果Pb、Cd的超标率分别为5.7%、7.8%,不同水果Pb、Cd的超标率差异显著,草莓Cd的超标率最高。研究区水果中重金属未对成人构成非致癌健康风险,而水果中的As和Cu对儿童构成了非致癌健康风险,As和Cu对水果重金属非致癌总指数的贡献超过70%,应特别关注水果中As和Cu的管控,以免造成较大的食源性危害。（4）重金属在水果与土壤中的含量水平关联性较低,水果中重金属的含量与水果富集重金属的能力关联度极高,应进一步查明水果重金属与土壤重金属形态的关系,并结合调整水果种植结构、筛选重金属低积累水果品种等方式降低水果重金属的健康风险。     

Economic analysis of ethanol production in California using traditional and innovative feedstock supplies

In this article, we estimate the costs of using alternative feedstocks to produce ethanol in a 40 million-gal facility in California’s San Joaquin Valley. Feedstocks include corn imported from Midwestern states and locally grown agricultural products such as corn, grapes, raisins, oranges, and other tree fruits. The estimated feedstock costs per gallon of ethanol include $0.92 for Midwestern corn, $1.21 for locally grown corn, $6.79 for grapes, $3.36 for raisins, $3.92 for citrus, and $1.42 for other tree fruit. Adjusting for coproduct values lowers the estimated net feedstock costs to $0.67/gal of ethanol for Midwestern corn, $0.96 for locally grown corn, $6.53 for grapes, and $3.30 for raisins. We also examine the potential increases in net revenue to raisin producers, made possible by having an alternative outlet available for selling surplus raisins.     

电感耦合等离子体质谱法快速测定苦荞茶中铜、铅、镉、钴、镍

建立了用硝酸-高氯酸消解样品,电感耦合等离子体质谱法(ICP-MS)测定苦荞茶中铜、铅、镉、钴、镍的方法.方法具有灵敏度高、检出限低、精密度好、基体干扰少、准确可靠、快捷、简便的特点.各元素方法检出限(3SD,μg/L)分别为:铜0.009、铅0.023、镉0.015、钴0.022、镍0.035;方法精密度(RSD,n=12)分别为:铜2.5%～3.0%、铅2.1%～2.3%、镉3.0%～3.8%、钴2.5%～2.6%、镍1.5%～1.9%;各元素加标回收率分别为:铜95.0%～105.0%、铅95.0%～105.0%、镉98.0%～105.0%、钴95.0%～105.0%、镍95.0%～105.0%.在线用铑作为内标95.0%～105.0%.方法经国家一级标准物质验证,测定值与标准值吻合.应用于实际样品测定,结果满意.     

高效液相色谱法测定藻类中的类胡萝卜素和叶绿素

提出了用高效液相色谱法测定藻类中类胡萝卜素和叶绿素的方法。采用丙国等有机溶剂提取藻类中的类胡萝卜素和叶绿素,然后在反相C18柱上进行分离。流动相选用二氯甲烷／乙腈／甲醇／水（22.5:9.5:67.5:0.5）,流速为1.0mL／min。用光度检测器检测报长为450um。叶黄素、α-胡萝卜素、β-胡萝卜素、叶绿素a和叶绿素b的平均回收串分别为99.1％,98.5％,99.4％,100.6％和99.9％,相对标准偏差分别为2.4％,5.6％,6.0％,4.1％和4.0％。     

Analysis of urinary biomarkers for exposure to alkyl benzenes by isotope dilution gas chromatography-mass spectrometry

A validated GC-MS method for the analysis of urinary metabolites of alkyl benzenes is reported. Metabolites for exposure to toluene, xylene and ethylbenzene were analyzed simultaneously using stable isotope substituted internal standards. The method entailed acidic deconjugation of urine samples followed by extractive alkylation with pentafluorobenzyl bromide as alkylating agent. The resulting pentafluorobenzyl derivatives of ortho-, meta-, para-cresol, mandelic acid (MA), hippuric acid (HA) and ortho-, meta-, para-methylhippuric acid (MHA) were then quantified by SIM. Optimized reaction conditions for the extractive alkylation step are reported. The derivatives were found to be sufficiently stable for overnight batch analysis. The LODs were below 0.1 micromol/L for the cresols and below 1 micromol/L for MA and the HAs. Within-batch precision for o-MHA was 7%, for m-MHA 5%, for p-MHA 5.2% and below 5% for the rest of the analytes.     

Dibenzomethanopentacene-Based Polymers of Intrinsic Microporosity for Use in Gas-Separation Membranes

Dibenzomethanopentacene (DBMP) is shown to be a useful structural component for making Polymers of Intrinsic Microporosity (PIMs) with promise for making efficient membranes for gas separations. DBMP-based monomers for PIMs are readily prepared using a Diels–Alder reaction between 2,3-dimethoxyanthracene and norbornadiene as the key synthetic step. Compared to date for the archetypal PIM-1, the incorporation of DBMP simultaneously enhances both gas permeability and the ideal selectivity for one gas over another. Hence, both ideal and mixed gas permeability data for DBMP-rich co-polymers and an amidoxime modified PIM are close to the current Robeson upper bounds, which define the state-of-the-art for the trade-off between permeability and selectivity, for several important gas pairs. Furthermore, long-term studies (over ≈3 years) reveal that the reduction in gas permeabilities on ageing is less for DBMP-containing PIMs relative to that for other high performing PIMs, which is an attractive property for the fabrication of membranes for efficient gas separations.     

Simultaneous quantification of five anthraquinones in rat plasma by high-performance liquid chromatography with fluorescence detection

A sensitive high-performance liquid chromatographic method with fluorescence detection (excitation 435 and emission 515 nm) was established and validated for quantification of five anthraquinones (aloe-emodin, rhein, emodin, chrysophanol and physcion) in rat plasma. Following a single-step liquid-liquid extraction, the analytes and internal standard (1,8-dihydroxyanthraquinone) were separated on a reversed-phase C(18) column with water-phosphoric acid-methanol as mobile phase at a flow rate of 1 mL/min. The linear ranges of the calibration curves were 6.5-1300 ng/mL for aloe-emodin, 20-4000 ng/mL for rhein, 40-8000 ng/mL for emodin, 15-3000 ng/mL for chrysophanol and 13-2600 ng/mL for physcion. The lower limit of quantification was 6.5 ng/mL for aloe-emodin, 20 ng/mL for rhein, 40 ng/mL for emodin, 15 ng/mL for chrysophanol and 13 ng/mL for physcion. The mean accuracy was 94.3-105.1% for aloe-emodin, 90.3-108.8% for rhein, 92.6-106.7% for emodin, 95.8-103.8% for chrysophanol and 98.7-101.2% for physcion. The within-batch and between-batch precisions were < or = 5.5% and < or = 13.4%, respectively. This method is suitable for determining the five anthraquinones in plasma simultaneously and thus investigating the pharmacokinetics of anthraquinones from Xiexin decoction in rats.     

Overview of Special Session B—Compositional and Structural Analysis of Biomass

Special Session B at the 29th Symposium on Biotechnology for Fuels and Chemicals was the first invited session at this symposium devoted to analytical methods. The special topic was added in response to numerous requests for information on new and innovative methods that could be applied in the growing renewable fuels industry. Presentation topics include analytical methods for the characterization and analysis of maize traits, tools for investigating cell wall limitations to enzymatic degradation, methods for customizing enzyme cocktails for biomass, new techniques for the analysis of carbohydrates, analytical methods that enhance our understanding of pretreatment, improved methods for monitoring process intermediates, and published standard analytical methods for biomass conversion processes.     

Normal Coordinate Analysis for Polymer Systems: Capabilities and New Opportunities

Normal coordinate analysis is an important tool in studying the structure, dynamics, and physical properties of polymer systems. In this article the capabilities of normal coordinate analysis (NCA) are explored in some detail. The use of the eigenvalues and eigenvectors from NCA is catalogued for a wide variety of purposes: for assigning or interpreting polymer spectra, for structural determination, for constructing force fields, for computing heat capacity and other thermodynamic properties, and for computing other physical properties. Examples are given for crystals, melts, and amorphous systems. Also described are methods for characterizing the normal mode vectors that are especially useful for larger systems, in which a large amount of data must be analyzed or where visualization or animation fails. Finally, a recently developed method for eliminating negative eigenvalues in systems with tens of thousands of atoms, trajectory averaging, is presented. Also described are several advances in numerical linear algebra for speeding up the diagonalization phase and for computing physical properties without requiring full diagonalization of the Hessian matrix.     

顶空固相微萃取-气相色谱-质谱联用分析纺织品中挥发性有机物

建立了顶空固相微萃取（HSSPME）-气相色谱（GC）-质谱（MS）联用测定纺织品中甲苯、4-乙烯基环己烯、苯乙烯、萘和1-苯基环己烯5种挥发性有机物（VOCs）的分析方法。选择聚二甲基硅氧烷（PDMS）作为萃取涂层,优化了SPME的萃取条件,包括平衡时间、萃取时间、萃取温度、顶空体积、离子强度、搅拌速度、解吸温度和时间以及GC—MS仪器条件。对于甲苯、4-乙烯基环己烯、苯乙烯、萘和1-苯基环己烯方法线性范围分别为0．087～870、3．32～3320、2．28～2280、0．015～150和0．050～50．0ng／g;检出限分别为0．005、0．042、0．670、0．008和0．011ng／g。实际样品加标回收率在80．1％～122％之间,RSD在0．8％～8．6％之间。方法符合纺织品中痕量VOCs的快速分析要求。     

傅里叶变换近红外光谱法同时定量分析水溶液中乙醇、果糖和葡萄糖

利用乙醇、果糖和葡萄糖在波数为14000-7500cm^-1范围内的吸收值,在近红外谱区用偏最小二乘法（PLS）对体系进行建模,并通过内部和外部样品校验确认最佳数据预处理方法。结果表明,乙醇在0.05-0.25L/L,果糖在0.01-0.05g/mL及葡萄糖在0.005-0.009g/mL的范围内外部校验模型较好的分别是在PLS中所用的一阶偏导（平滑点数是5）、二阶偏导（平滑点数是5）和直线消除法的数据预处理方法所建立的模型,其外部校验预测结果的相对误差在2%左右。此方法具有可同时测定不同样品,简便快速及成本低等优点。