气相色谱法测定氟里昂—12

本文介绍了用102型气相色谱仪FID,以407有机高分子微球吸附剂为固定相测定氟里锦—12的方法.该方法可以实现F—12、F—11的完全分离,方法最小检测量F—12为5ppm.     

氟虫腈对斑马鱼和小菜蛾毒性的手性选择性研究

手性农药分子的不同对映体在环境中的降解速率和对于生物的毒性可能存在很大的差异,因此拆分并使用对靶标生物毒性较高或对非靶标生物毒性较低的单一或浓缩的对映体配方可以有效地降低杀虫剂的环境风险.本文用手性柱拆分了一种广泛使用的手性农药,氟虫腈的两种对映体,研究了这两种对映体和消旋体对靶标生物小菜蛾和非靶标生物斑马鱼的急性毒性.结果表明氟虫腈对受试靶标和非靶标生物的毒性均无手性选择性,说明无法通过对氟虫腈进行手性拆分并使用单一对映体配方来降低氟虫腈的环境风险.这一结论间接支持了农业部新近出台的禁止氟虫腈用于防治农田害虫的政策.     

Analysis of diffusion-adsorption equivalency of landfill liner systems for organic contaminants

The equivalence between multilayered barriers regarding diffusion and adsorption is analyzed by means of an analytical method. The bottom boundary of the liner system is defined by assuming concentration continuous and flux continuous conditions of the contaminant between the bottom liner layer and the underlying soil. Five different liner systems were compared in terms of solute breakthrough time. The results of the analysis show that breakthrough time of the hydrophobic organic compounds for a 2-meter-thick compacted clay liner (CCL) can be 3-4 orders of magnitude greater than the breakthrough time for a geosynthetic clay liner (GCL) composite liner. The GM/GCL and GM/CCL composite liner systems provide a better diffusion barrier for the hydrophilic organic compounds than that for the hydrophobic compounds due to their different Henry's coefficient. The calculated breakthrough times of the organic contaminants for the Chinese standard liner systems were found to be generally greater than those for the GCL alternatives, for the specific conditions examined. If the distribution coefficient increases to 2.8 for the hydrophobic compounds or 1.0 for the hydrophilic compounds, the thickness of the attenuation layer needed to achieve the same breakthrough time as the standard liner systems can be reduced by a factor of about 1.9-2.4. As far as diffusive and adsorption contaminant transport are concerned, GM or GCL is less effective than CCL.     

云南抚仙湖流域磷化工对农田土壤和农作物的影响

通过对云南抚仙湖流域磷化工厂附近农田和区域内地表径流污染物含量进行调查分析,结果表明距磷化工厂越近,农田灌溉水、土壤、农作物中污染物含量越高。磷化工生产排放的废水和废渣淋溶废水严重污染了附近农田灌溉水,从而造成农田土壤氟、磷积累,最高分别超过对照农田土壤氟、磷含量35和37倍。相关分析结果表明农作物茎、叶蓄积的高浓度氟、磷主要来源于受磷化工排放废水和废渣污染的农田土壤。     

新生产空调客车内挥发性有机物浓度水平和来源分析

选取某厂家新生产的、下线时间不超过28d的53座新空调客车,在车辆处于静止状态下采用二次热解析-毛细管气相色谱/质谱联用法测量新空调车内挥发性有机物的分布特征和浓度水平.根据NIST02标准谱图进行匹配检索,结合色谱保留时间定性,共定性检出33种挥发性有机物,包括烷烃(15种、45.4%)、芳香类化合物(9种、27.3%)、醇(4种、12.1%),酮(3种、9.1%)、酯(2种、6.1%),且大多集中在C6～C10的范围内.新车内浓度最高的前5种挥发性有机物分别为癸烷(8.01 mg/m3)、3-甲基己烷(7.10mg/m3)、庚烷(5.10mg/m3)、异庚烷(4.20 ms/m3)和1-甲基,3-乙基苯(3,56 mg/3),总挥发性有机物TV012,52.5mR/m3.烷烃主要来源于空调车内部保温材料如聚氨酯(PU)发泡海绵或者聚乙烯(PE)发泡材料的释放,而车内检出的芳香族化合物主要来自汽车内饰用胶粘剂、密封胶等的释放.     

室内环境中微生物与挥发性有机化合物相关性的初步探讨

采集室内环境空气中菌落,经培养后分别将微球菌属、葡萄球菌属、芽孢杆菌属、曲霉属、青霉属的纯培养物转接到培养皿上,然后放入环境测试舱密闭环境中进行放大培养。分析菌落放大培养前后环境测试舱内空气中VOCs组成及其含量水平。结果表明,检测的100种挥发性有机化合物中有42种化合物在扩大培养后浓度升高,而30种化合物的浓度下降。微生物在生长代谢过程中既能分解空气中的一些毒害性有机污染物,也能产生一些毒害性有机污染物。     

浙江北部地区地下水高氟和高砷分布特点和建议

在分析了浙江北部地区地下水类型、特征、地下水开采现状和水位变化基础上,通过对不同类型地下水深井样品测试数据的研究,查明了区域地下水高氟和高砷的分布特点.高氟区主要出现于妙西花岗岩裂隙水和白雀岩溶水分布区,高砷区主要位于南浔第Ⅱ承压含水层局部区域.研究认为高氟和高砷地下水分布区与区域土壤和浅层地下水中总氟和总砷含量没有直接联系,深井地下水中的高氟和高砷主要与深部断裂构造有关.研究地区的这种高氟和高砷地下水目前仍然为很多居民所饮用,作者认为长期饮用这种高氟和高砷地下水容易导致地方病的产生,建议在高氟和高砷地下水分布区停止生活用水开采,有条件的企事业单位应实行改水方案.     

Characterization of organic matter in total suspended particles by thermodesorption and pyrolysis-gas chromatography-mass spectrometry

The organic matter in tropospheric aerosol plays an important role in atmospheric physical and chemical processes. The bulk of organic matter, representing a significant proportion of the total suspended particulate (TSP) mass, is bound to polymeric material whose structure and properties are largely unknown. Here we used thermodesorption gas chromatography/mass spectrometry (Td- GC/MS) to study organic compounds of low molecular mass and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) to characterize the chemical structure of macromolecules in TSP samples collected in di erent seasons from di erent sites in Guangzhou. n-Alkanes, fatty acids and nitriles were the predominant compounds in the thermodesorption products, whereas aromatics, fatty acids, nitriles and n-alkanes/alkenes were the major compounds in the pyrolysates. The results indicated that aromatics were main units in macromolecules. The fatty acids and nitriles formed from carboxylic ammonium salts were detected in both thermodesorption products and pyrolysates at a certain concentration, indicating the importance of these compounds in TSP formation. The TSP source mainly determined the occurrence of compounds in samples from urban, suburban and forest sites, whereas the TSP source and formation process maybe controlled the seasonal variation in compounds detected. High levels of nitriles in summer samples from suburban and forest sites coincide with the release of ammonium from the land and of fatty acids from vegetation at these sites.     

沈阳地区水环境和生物样品中全氟化合物的污染分布特征

采用高效液相色谱/电喷雾负电离源串联质谱法对沈阳市各类水环境和生物样品中全氟化合物(PFCs)进行测定,研究了PFCs的河流分布及季节分布特征.同时,对通过饮用水及家禽和鱼摄入全氟辛烷磺酸(PFOS)和全氟辛酸(PFOA)的人体健康风险进行了评价.结果表明,沈阳市各类水环境样品中总PFCs浓度范围为nd～6.01ng·L-1,平均浓度为5.23ng·L-1.PFOS和PFOA是沈阳地区所有水环境样品中最主要的PFCs污染物,浓度范围分别为nd～2.83ng·L-1和nd～5.71ng·L-1,平均浓度分别为1.11和2.13ng·L-1.细河的PFOS含量最高,约为浑河PFOS含量的2倍,蒲河PFOS含量的3倍.一些PFCs化合物之间呈正相关关系,说明其可能具有相同的来源.PFOS与PFOA之间无相关关系,由此推断沈阳水体中二者具有不同来源.浑河流经沈阳市时,PFOS和PFOA浓度升高.流经沈阳市区后,PFOS和全氟己烷磺酸钾(PFHxS)浓度明显升高.细河中PFHxS也有检出,表明沈阳市是周边水体中PFOS及PFHxS的主要污染来源.丰水期地表水中PFOS和PFOA浓度与枯水期相比没有明显差异,但丰水期水中PFCs组成更为丰富,出现了大量全氟庚酸(PFHpA).沈阳地区自来水中PFOS和PFOA浓度平均值分别为0.39和0.85ng·L-1,最高浓度分别为1.16和2.55ng·L-1,均低于美国饮用水健康参考值.沈阳生物样品中PFOS和全氟十一酸(PFUnDA)是最普遍的化合物.总PFCs平均含量在鱼样品中为6.59ng.g-1(以干重计),鸡和鸭血清样品中分别为1.65和0.69ng·mL-1,鸡和鸭肝脏样品中分别为0.41和1.68ng.g-1(以干重计),与文献报道相比处于较低水平.     

氧化铝负载镧去除水中F-的研究

通过固相反应合成了氧化铝负载的氧化镧吸附剂并研究了其对水中F-的吸附.结果表明.合成的材料对F-有很好的去除效果,最大吸附量达到53.4 mg·g-1;适当提高吸附温度和氧化镧负载量都能在一定范围内提高吸附量;较低的固相反应焙烧温度有利于提高去除率,随着焙烧温度的升高,吸附量从170℃焙烧的42.2 mg·g-1下降到了350℃焙烧的32.9 mg·g-1.同时,吸附剂表现出了很好的适应性,在较宽的pH范围内都能保持较高的吸附量.