焦化废水中痕量苯并(a)芘的固相萃取和GC-MS检测方法

基于固相萃取(SPE)和气相色谱/质谱联用技术(GC-MS),建立了一种焦化废水中痕量苯并(a)芘(BaP)的定量分析方法。BaP水样添加甲醇改性后经SPE富集净化、二氯甲烷洗脱、氮吹浓缩、二氯甲烷或乙腈定容后采用GC-MS进行定量分析。结果表明:在优化的样品前处理和分析条件下,BaP标准曲线的线性相关系数R2>0.99,方法回收率为79.6%~85.5%,方法检出限和定量限分别为4.33 ng/L和14.45 ng/L。该方法应用于内蒙古某焦化厂二级生化出水加标样品中BaP的测定,得到BaP的回收率为83.3%~89.3%,表明其灵敏度高、选择性好,适用于焦化废水中痕量BaP的定量检测。     

乙酰化滤纸层析——荧光分光光度法测定清洁水中苯并(a)芘

本方法介绍清洁水中的微量苯并(a)芘(简称BaP)的分析。清洁水中微量多环芳烃(简称PAH)经环己烷萃取后,再将萃取物用无水硫酸钠脱水并浓缩至0.05毫升以下,然后直接经乙酰化滤纸层析,其中BaP斑点经丙酮洗脱后用荧光分光光度计进行定性、定量测定。此法具有设备简单、操作方便、污染少等优点,本法最低检测限为2.5毫微克/升。一、试剂 BaP标准溶液的配制:称取500毫克BaP固样品(英国进口)于50毫升容量瓶中,用少量苯溶解后,再加     

苯并(a)芘分析用水样的保存和处理

苯并(a)芘(简称BaP)作为一种较普遍存在的环境污染致癌物早已受到人们的重视.大气悬浮颗粒物、水、沉积物和食品等样品中的BaP测定方法已有大量报道,其测定结果准确与否,很大程度上取决于样品的保存和处理,水中BaP的定量测定更是如此.水中BaP除天然形成的部分外,主要来源于工业废水,如焦化、炼油、沥青冷却浇铸、石油化工、塑料、颜料、页岩油废水、柏油和沥青道路的冲洗水等,上述各行业和橡胶加工业、内燃机、柴油     

薄层扫描法测定大气飘尘中苯并[a]芘

应用快速法提取样品和薄层扫描技术比洗脱斑点法测定苯并[a]芘(简称BaP)简易、安全。此法3小时可分析6个提取样品,方法回收率95％以上,最低可检量为1毫微克BaP。     

RA-915M测汞仪直接测定土壤和沉积物中总汞

采用RA-915M汞分析仪测定土壤和沉积物中总汞,建立了一种快速直接的分析测定方法。该方法测定土壤和沉积物样品时不需要任何消解处理,操作简单,成本低,测量时间较短。通过对标准样品和实际样品进行测定,结果显示该方法有较低的检出限(0.0024mg/kg)和较高的精密度(RSD≤10.5%),而且数据结果准确、可靠。     

柴油中元素硫含量的分析

采用气相色谱/质谱(GC/MS)联用仪,测定柴油中元素硫含量的方法.该方法采用直接进样,完成一个样品分析只需20 min,最小检测量为4.5×10-11g.其线性范围宽可为0.01～100 mg/L,线性相关系数大于0.9995;该方法精确度高,相对标准偏差<5%,回收率为93.0%～106.2%.与以往的其它元素硫分析方法相比,更简便、快速、灵敏,且无干扰.     

利用加速器质谱仪进行快速~(129)I检测的方法研究

加速器质谱法是~(129)I最灵敏的检测方法。传统方法分析样品时通常需要复杂的化学制样流程,对样品中碘元素进行分离、富集和纯化,测试周期较长,成本高。在核应急分析等类型的应用研究中,需要对大批量样品中的~(129)I含量开展快速检测,针对此类应用需求特点,本研究尝试开发一种快速、流程简便并且成本低廉的~(129)I-AMS检测方法。以三种已知~(129)I水平的国际标准物质作为研究样品,将干燥和研磨均匀化的样品粉末直接与加入过本底碘的电热导体介质(Nb粉末)混合后压入靶座,实现快速制靶,进行加速器质谱测量,再结合制靶时称量的相关质量关系数据就能直接计算得出原始样品中的~(129)I活度。通过对测量数据与已知值进行比较分析验证了方法的可靠性,估算方法的探测下限可达0.15μBq?g~(-1)。     

三种分离测定苯并(a)芘方法的比较

大气悬浮颗粒物中苯并(a)芘(简称BaP)的测定方法国内外均有大量报道.近年来,我们主要采用三种不同的方法测定大气样品中BaP的含量.方法1:咖啡因硅胶薄层层析(TLC)-小斑点窄基线荧光法;方法2:乙酰化滤纸层析(PC)-窄基线荧光法;     

大气飘尘中有机污染物的分离、分析与致突变活性的研究

对北京地区几个点的大气飘尘样品中的有机污染物进行了分离(分成六个组分)、分析(脂肪烷烃及多环芳烃),并对各组分进行Ames试验(TA98菌株,加与不加S_9)研究其致突变活性.试验结果:需代谢活化的致突变物集中存在于多环芳烃和吲哚与咔唑类的氮杂环化合物;直接致突变物集中存在于有极性的和醚溶性化合物;致突变活性与所用的剂量在实验范围内呈线性关系,但并不总与样品中的BaP含量相关.     

全自动固相萃取-高效液相色谱-荧光检测法测定生活饮用水中苯酚

建立全自动固相萃取-高效液相色谱法测定饮用水中苯酚的方法。样品经过全自动固相萃取仪的预处理后,通过XBridger-C18色谱柱分离,以甲醇+0.01mol/L乙酸-乙酸铵缓冲溶液为流动相进行洗脱,于激发波长230nm发射波长320nm荧光检测,测定结果表明,线性范围良好,回收率90%~93%,相对标准偏差1.3%~3.5%。该方法操作简单方便,分析快速、准确,灵敏度高,。     

多壁碳纳米管修饰丝网印刷电极同时检测水中苯二酚异构体的研究

采用丝网印刷技术和滴涂法制备了一种可抛型的多壁碳纳米管修饰丝网印刷电极,并将其用于水中的对苯二酚、 邻苯二酚和间苯二酚等苯二酚异构体的同时检测.苯二酚在此修饰电极上的循环伏安行为考察显示,该电极可较好地区分3种异构体的氧化峰,对其氧化还原反应有明显的电催化作用;以差示脉冲伏安法检测对苯二酚、 邻苯二酚和间苯二酚的混合水样,其峰电流与浓度分别在8.20×10^-6～1.00×10^-3、 8.20×10^-6～1.00×10^-3和1.64×10^-5～1.16×10^-3 mol·L^-1范围内呈良好的线性关系,检出限分别达4.34×10^-6、 3.42×10^-6和6.70×10^-6 mol·L^-1;对污染水样进行测定,加标回收率为96.2%～104.9%.研究结果表明,多壁碳纳米管修饰的丝网印刷电极可用于苯二酚异构体污染水样的现场快速检测.     

The use of rice crop residues as a non-commercial energy source in the developing world: The energy and environmental implications

The potential biomass energy that can be derived from the harvest of rice crop residues is calculated for three methods of crop production. The potential energy available amounts to 3.70 × 10¹⁰ J ha^?1 year^?1 for traditional methods, 7.93 × 10¹⁰ J for the labor-intensive and 8.36 × 10¹⁰ J for the capital-intensive methods. The net energy benefits available for cooking, heating and biogasification are calculated on a per hectare basis taking into account the costs of collection, transportation and processing. The amounts of energy available for cooking and heating range from 3.70 × 10⁹ to 8.33 × 10⁹ J ha^?1, and the amounts of energy for methanol use range from 1.85 × 10⁹ to 4.17 × 10⁹ J ha^?1 year^?1.The ecological problems associated with soil erosion, nutrient loss and pesticide use are evaluated in terms of the compensatory energy costs involved, and the resultant net energy balance for each method of rice production is calculated. The net energy available per hectare for the traditional method is 3.43 × 10¹⁰ J, for the labor-intensive method, 7.25 × 10¹⁰ J and for the capital-intensive method, 7.02 × 10¹⁰ J. The harvest of rice crop residues in the developing world could provide up to 5.80 × 10¹⁸ J year^?1.The use of rice crop residues is investigated within the context of the rural village energy system. The prospects for the use of rice crop residues are evaluated in relation to alternative energy sources and it is concluded that regional residue harvest programs should be implemented cautiously, integrating soil management and environmental planning procedures where appropriate.     

A simple and sensitive method for the determination of 4-n-octylphenol based on multi-walled carbon nanotubes modified glassy carbon electrode

A simple and sensitive electroanalytical method was presented for the determination of 4-n-octylphenol (OP) based on multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrode (GCE). OP was directly oxidized on the MWCNTs/GCE, and the electrochemical oxidation mechanism was demonstrated by a one-electron and one-proton process in the reaction. The oxidation peak current of OP was significantly enhanced by the use of MWCNTs/GCE compared with those of bare glassy carbon electrode, suggesting that the modified electrode can remarkably improve the performance for OP determination. Factors influencing the detection processes were optimized. Under these optimal conditions, a linear relationship between concentration of OP and current response was obtained in the range of 5×10^-8 to 1×10^-5 mol/L with a detection limit of 1.5×10^-8 mol/L and correlation coefficient 0.9986. The modified electrode showed good selectivity, sensitivity, reproducibility and high stability.     

流动注射化学发光测定痕量亚硝酸根的研究

基于NO_2~-对I_2-EDTA光化学反应的抑制作用和I_2与鲁米诺的化学发光反应,建立了痕量亚硝酸根的流动注射化学发光分析方法.试验并选择了最佳条件,测定了天然水中亚硝酸根的含量,回收率在93—103.5％,方法线性范围为1.0×10~(-7)—4.0×10~(-6)mol.L~(-1),检测限为1.1×10~(-6)mol.L~(-1).对2.0×10~(-7)mol·L~(-1)NO_2~-进行测定,相对标准偏差为2.2％.     

基于电生理信息的两种桑科植物叶片细胞代谢能比较

植物的细胞代谢能可以表征植物的生理活性和源库状况,而植物的细胞代谢能可由细胞的生理电容、生理电阻和生理阻抗来表征.本研究以桑科植物构树(Broussonetia papyrifera)和桑树(Morus alba)为例研究了不同夹持力下生理电阻、生理阻抗和生理电容的特征.先依据吉布斯自由能方程和Nernst方程构建模型...     

Rapid and simple spectrophotometric determination of persulfate in water by microwave assisted decolorization of Methylene Blue

A rapid and simple method for determination of persulfate in aqueous solution was developed. The method is based on the rapid reaction of persulfate with Methylene Blue(MB) via domestic microwave activation, which can promote the activation of persulfate and decolorize MB quickly. The depletion of MB at 644 nm(the maximum absorption wavelength of MB) is in proportion to the increasing concentration of persulfate in aqueous solution. Linear calibration curve was obtained in the range 0–1.5 mmol/L, with a limit of detection of 0.0028 mmol/L. The reaction time is rapid(within 60 sec), which is much shorter than that used for conventional methods. Compared with existing analytical methods, it need not any additives, especially colorful Fe2+, and need not any pretreatment for samples, such as p H adjustment.     

基于生态保护目标的太子河下游河道生态需水量计算

河流生态需水量计算是进行生态水权分配的一项基础性工作,是生态环境保护和水资源配置的依据.随着社会经济的发展,流域水资源短缺和生态环境问题日益突出.针对太子河下游河段水资源开发利用现状及存在的生态环境问题,在确定生态保护目标的基础上,采用月保证率法和生态水力学法计算下游河道不同等级生态需水量,既可以从各月角度反映河道生态需水是一个与自然径流相适应的过程,又注重水生生物的关键期和生境需求.通过Tennant法验证月保证率法和生态水力学法计算结果可靠,最终确定太子河下游河道最小、适宜和理想等级年生态需水量分别为:5.31×108m3、8.52×108m3和12.17×108m3,而且现状流量可以满足最小生态需水量的要求.     

Precision of the radiochemical OH measurement method

Twenty-eight radiochemical ¹⁴C tracer measurement of tropospheric hydroxyl radical (OH) concentrations were obtained at a rural site near Washington State University, Pullman, WA (117°W, 47°N). Diurnal OH concentration variations were observed for the five days between 9 August and 14 August 1990. These data made it possible to estimate the midday precision and detection limit of the radiochemical OH measurement method. Experiments performed at a peak O₃ photolysis rate J (O(¹D)) of (3.0±0.2) × 10⁻⁵ s⁻¹ yielded a mean midday OH concentration of (5.6±0.1 (1σ)) × 10⁶ cm⁻³. Other data put an upper bound of 16% on fluctuations of instrument sensitivity. Low-light or nighttime background OH concentrations were less than (2.6±2) × 10⁵ cm⁻³. A lower detection limit of 10⁵ cm⁻³ was obtained when extra care was taken with the low-level ¹⁴C counting procedure.