分散液液微萃取-石墨炉原子吸收光谱法测定环境水样中的痕量镉

建立了分散液液微萃取分离富集一石墨炉原子吸收光谱法测定环境水样中痕量镉的新方法。以二乙基二硫代氨基甲酸钠为螯合剂、四氯化碳为萃取剂、丙酮为分散剂,详细考察YpH值、螯合剂质量分数、萃取剂体积、萃取时间等因素的影响。在优化的实验条件下,方法对水样中镉的检出限为4．2ng-L^-1,线性范围是20-300ng-L^-1,测定结果的相对标准偏差为3．5％,富集倍数达103。将建立的方法应用于三种实际环境水样中镉的检测,加标回收率在92％-108％范围内。本方法具有灵敏、准确、快速、环保的特点,是一种分析水样中痕量镉的较好方法。     

氢化物发生原子荧光光谱法测定清洁水中的微量锡

利用AFS～ 820双道原子荧光光度计对水中微量锡的测定方法进行研究分析,结果表明:该方法检出限为0.002 ng/mL,相对标准偏差(RSD)为3.05％ ～5.95％,加标回收率为94.0％ ～ 104.7％.使用原子荧光光谱法测定清洁水中微量锡具有灵敏度高,准确度、精密度好,仪器操作方便等优点,适宜水中微量锡的测...     

氢化物发生原子荧光光度法测定水中锑的不确定度评定

介绍了原子荧光光度法测定水中锑的不确定度评定方法,分析和识别在测定过程中的不确定度来源,较为全面地评定了测量不确定度,最后计算出测定结果的合成标准不确定度和扩展不确定度.结果表明,标准溶液配制过程和标准曲线拟合引起的不确定度是原子荧光光度法测定水中锑含量不确定度的主要来源.     

毛细管柱气相色谱法测定环境空气中的樟脑

采用毛细管柱气相色谱氢火焰离子化检测器测定环境空气中的樟脑,选择硅胶为吸附剂,甲醇/丙酮混合溶剂(体积比90∶10)为解析剂.方法在0.544 mg/L～109 mg/L范围内线性良好,检出限为0.06 mg/L,当采样体积为20 L时,最低检出质量浓度为0.003 mg/m3,标准溶液平行测定的RSD≤3.8％,空白...     

Quantification, morphology and source of humic acid, kerogen and black carbon in offshore marine sediments from Xiamen Gulf, China

Three types of macromolecular organic matters (MOMs), i.e. humic acid (HA), kerogen+black carbon (KB), and black carbon (BC) were extracted from marine sediments of Xiamen Gulf, southeast of China. The chemical composition, morphological property and source of the three extractions were characterized by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS) and scanning electron microscope (SEM). The results showed that KB was the predominant fraction in MOMs, which accounted for 61.79%-89.15% of the total organic content (TOC), while HA consisted less than 5%. The relative high contents of kerogen and BC, and low contents of HA in the samples indicated that anthropogenic input might be the major source of organic matter in marine sediments near the industrial regions. The characterization of SEM, not only revealed morphological properties of the three fractions, but also allowed a better understanding of the source of MOMs. The δ 13 C values of the three fractions suggested that materials from terrestrial C 3 plants were predominant. Furthermore, the anthropogenic activities, such as the discharge of sewage, coal and biomass combustion from industry nearby and agricultural practices within drainage basin of the Jiulong River, were remarkably contributed to the variations in δ 13 C values of MOMs in the offshore marine sediments.     

Simultaneous preconcentration of cadmium and lead in water samples with silica gel and determination by flame atomic absorption spectrometry

A new method that utilizes pretreated silica gel as an adsorbent has been developed for simultaneous preconcentration of trace Cd(Ⅱ) and Pb(Ⅱ) prior to the measurement by flame atomic absorption spectrometry. The effects of pH, the shaking time, the elution condition and the coexisting ions on the separation/preconcentration conditions of analytes were investigated. Under optimized conditions, the static adsorption capacity of Cd(Ⅱ) and Pb(Ⅱ) were 45.5 and 27.1mg/g, the relative standard deviations were 3.2% and 1.7% (for n = 11), and the limits of detection obtained were 4.25 and 0.60 ng/mL, respectively. The method was validated by analyzing the certified reference materials GBW 07304a (stream sediment) and successfully applied to the analysis of various treated wastewater samples with satisfactory results.     

石墨炉原子吸收光谱法测定土壤中痕量钻

建立了硝酸－氢氟酸－盐酸混酸体系微波消解土壤样品,石墨炉原子吸收分光光谱法测定土壤中痕量钴的方法。通过对标准土样的测定结果表明,该方法容易操作、准确、可靠。     

锅炉改造项目环境影响评价实证分析

本文以锅炉“煤改气”项目为例,在项目施工期、运营期产生的环境影响进行评价,并提出相应的环境保护措施。为环保部门和企业管理提供理论依据,并为锅炉改造类项目污染预防治理提供实践经验,最大限度降低项目建设对周围环境的不利影响,推动“煤改气”项目的可持续发展。     

Simple removal of dioxins by injecting combustion gas into water

A simple, low-cost method for suppression of dioxins/furans (hereinafter referred to as dioxins) is required because many middle- and, especially, small-scale incinerators have fallen into disuse or have been dismantled because of the high running and system costs of measures for the suppression of dioxins. Therefore, the purpose of the present study was to develop a simple removal method for dioxins from combustion gas and to evaluate the basic removal rate of dioxins. The removal method for suspended matter in a gas mixture (cold model) and dioxins in exhaust gases (hot model) has been investigated by means of gas injection into water, the mechanism of which is that the suspended matter in the gas gathers at the gas–liquid interface. In the cold model, the removal ratio of fine particles (R_P) by gas injection into water was reproduced well by the following equation: R_P (%) = 100 × {1−exp(−0.8 · S_S · t_C)}, where S_S (cm²/cm³) is the specific surface area of bubbles and t_C (s) is the residence time of bubbles in water. The removal ratio of fine particles increased as the product S_s · t_C increased. In a hot model using the exhaust gas from combustion experiments of polyvinyl chloride, the removal ratio of dioxins (R_D) by injecting the exhaust gas into water was estimated by the following equation: R_D (%) = 100 × {1−exp(−0.8 · S_S · t_C · C_D0 ^0.07)}, where C_D0 [ng/cm³ (at standard temperature and pressure)] is the dioxins concentration in the exhaust gas before injection into water. R_D depends greatly on the specific surface area of bubbles and the residence time of the bubbles in water, and only weakly on the dioxins concentration in the exhaust gas. Injection of the exhaust gas into water has been shown to be effective and was evaluated as a simple method for the removal of dioxins from exhaust gas.     

微捕集技术在气相色谱分析空气中苯系物的应用

微捕集实际上是一种动态顶空技术。微捕集技术通常处理小体积的样品,应用小流量气体吹扫和小尺寸吸附管捕集,与仪器在线联接成一体的直接进样分析方法,不需要柱前冷聚焦和柱前分流的过程。该技术具有较好的应用前景。