液-液微萃取气相色谱法测定小量水样中痕量硝基苯

使用 FID检测器和 DB-1大口径毛细柱不需要对有机相进行干燥处理。借助 1 0 ml容量瓶和自制的玻璃吸管 ,不必进行两相分离操作 ,萃取和取样操作均可在容量瓶中一次完成。利用有溶剂效应的柱温程序提高了柱效和检测灵敏度。 1 0 ml水样可获得 0 .5 μg/ L的检测下限。方法的精密度优于 4 % ,回收率大于 95 %。     

蒸馏水吸收直接进样气相色谱法测定空气中的甲醛

用蒸馏水吸收富集室内空气中的甲醛,直接进样,经毛细管柱GC/FID测定样品中的甲醛,以保留时间定性,以峰面积定量。     

激光散射法和便携式氢火焰离子化检测器法直读监测油烟排放

餐饮业油烟排放具有排放浓度不稳定、波动较大、排放时间短等特性,存在瞬时排放高值现象,油烟"看得见"和"闻得着"的问题依然存在,因此对油烟实现快速、及时、直读监测尤为必要。基于一种浓度可控且稳定的油烟产生技术,对直读激光散射法与经典手工称重法测定油烟颗粒物浓度值的数据线性关系进行了分析,发现2种方法数值的相关系数达0.99,通过直读修正激光散射法可以有效地测定油烟颗粒物浓度,并测定了不同水汽含量下油烟颗粒物排放情况,发现当相对湿度超过70%时,油烟颗粒物浓度测定值会发生突变。使用便携式氢火焰离子化检测器法(FID)和光离子化检测器法(PID)测定了不同油温下油烟中非甲烷总烃(NMHC)浓度,发现FID对油烟中NMHC的变化反应及时,能够较好地测定油烟中挥发性有机物的排放量。     

室内空气中芳香烃的测定与污染源模拟

采用Ｔｅｎａｘ树脂吸附－热解吸／氢火焰气相色谱法定量测定室内空气中芳香烃类有机的。现场采样测定了某办公楼装修前后室内空气环境中芳香烃浓度。     

Development,validation and application of a method to analyze phenols in water samples by solid phase micro extraction-gas chromatography-flame ionization detector

In this work the development, validation and application of method using Solid Phase Microexctration (SPME) for the analyses of five pollutants (phenol, 2-nitrophenol, 2,4-dimethylphenol, 2,4-dichlorophenol and 4-chloro, 3-methyl phenol) in supplying water, using gas chromatography (GC) with flame ionization detector (FID) is described. The optimal conditions obtained for SPME were: fiber type: Poliacrylate (PA); extraction time: 40 minutes; extraction temperature: 70°C; amount of salt added to sample (NaCl): 15%; desorption temperature: 8 minutes. The parameters studied in the method validation were: limit of detection (0.3 and 3.5 μ g.L^{? 1}); precision, measured by the variation coefficient (between 2.1 and 8.8%); calibration curve and linearity, by using the external standardization method (between 1 and 50 50 μ g.L^{? 1}). After the methodology development, samples of water collected in Atibaia River (São Paulo - Brazil) were analyzed, using the optimized methodology. Three water samples collected in the rain season showed a peak with retention time close to 4-chloro, 3 methyl phenol further analyzed by Gas Chromatography-Mass Spectrometry for the identity confirmation. In spite of the fact that none target compounds were found in the river water samples analyzed, the presence of two phenols different from those investigated (p-terc butyl phenol; butylated hydroxytoluene) were detected. These results together with the results of the limit of detection (that showed to be lower than the maximum concentration of phenols demanded by different environment control agencies), and the results of the validation, indicate the applicability of this method for the analysis of selected phenols in river water samples.     

Field Detector Evaluation of Organic Clay Soils Contaminated with Diesel Fuel

Due to numerous types of uncontrolled petroleum releases into the environment such as leaking storage tanks, spills, and improper disposal of petroleum wastes, there is a need for quicker, more efficient methods to determine the levels of soil contamination for site remediation. The portable field detectors used most often in preliminary site evaluations are the flame ionization detector (FID) and the photoionization detector (PID). This research explored the relationship between these two instruments in analysis of two clay soil sites contaminated with diesel fuel. As in previous research, a log-log linear correlation was found between the PID and FID instruments for diesel fuel-contaminated soil at each site (R 2 > 0.91). Also, the correlation factors (0.64 and 0.60) between the field instruments at each site were found to be similar. It was asserted that either field instrument can be used to delineate the diesel fuel contamination at that site based upon a previously calculated correlation between the two instruments, and an overall numerical correlation between the field instruments can be used at various sites of similar soil and contamination characteristics. The implementation of the relationships between these two instruments could facilitate and accelerate site characterization in the future.     

Brazilian Oil Spills Chemical Characterization--Case Studies

In the last decade, PETROBRAS has experienced some significant oil spills cases and the PETROBRAS Research Center has played an important role in the company emergency response program by characterizing the spilled oil, monitoring the affected ecosystem, determining the fate of the oil in the environment, and, subsequently, helping the company in assessing the environmental damage. This paper presents the use of advanced chemical analytical techniques (GC/FID, P&T/GC/PID and GC/MS) in some Brazilian oil spill studies in order to determine fractions and individual petroleum hydrocarbons in different matrices such as water, groundwater, sediment, sand, fish and the spilled oil itself. The spill studies encompassed crude and fuel oil releases on land and coastal ecosystems, related to the incidents in Guanabara Bay (Rio de Janeiro), Barigui and Iguassu Rivers (Parana) and Sao Sebastiao Channel (Sao Paulo). Total petroleum hydrocarbons (TPH), n -alkanes, isoprenoids, unresolved complex mixtures (UCM), volatile monoaromatic compounds--benzene, toluene, ethylbenzene and xylenes (BTEX), parent and alkylated homologues polycyclic aromatic hydrocarbons (PAH), and terpanes and steranes were characterized for determining correlation to the spilled oil and other known oil sources and environmental assessment. Some of the acute ecotoxicity data for water and sediment samples is also presented.     

Volatile organic compounds at swine facilities: A critical review

Volatile organic compounds (VOCs) are regulated aerial pollutants that have environmental and health concerns. Swine operations produce and emit a complex mixture of VOCs with a wide range of molecular weights and a variety of physicochemical properties. Significant progress has been made in this area since the first experiment on VOCs at a swine facility in the early 1960s. A total of 47 research institutions in 15 North American, European, and Asian countries contributed to an increasing number of scientific publications. Nearly half of the research papers were published by U.S. institutions.Investigated major VOC sources included air inside swine barns, in headspaces of manure storages and composts, in open atmosphere above swine wastewater, and surrounding swine farms. They also included liquid swine manure and wastewater, and dusts inside and outside swine barns. Most of the sample analyses have been focusing on identification of VOC compounds and their relationship with odors. More than 500 VOCs have been identified. About 60% and 10% of the studies contributed to the quantification of VOC concentrations and emissions, respectively. The largest numbers of VOC compounds with reported concentrations in a single experimental study were 82 in air, 36 in manure, and 34 in dust samples.The relatively abundant VOC compounds that were quantified in at least two independent studies included acetic acid, butanoic acid (butyric acid), dimethyl disulfide, dimethyl sulfide, iso-valeric, p-cresol, propionic acid, skatole, trimethyl amine, and valeric acid in air. They included acetic acid, p-cresol, iso-butyric acid, butyric acid, indole, phenol, propionic acid, iso-valeric acid, and skatole in manure. In dust samples, they were acetic acid, propionic acid, butyric acid, valeric acid, p-cresol, hexanal, and decanal. Swine facility VOCs were preferentially bound to smaller-size dusts.Identification and quantification of VOCs were restricted by using instruments based on gas Chromatography (GC) and liquid chromatography (LC) with different detectors most of which require time-consuming procedures to obtain results. Various methodologies and technologies in sampling, sample preparation, and sample analysis have been used. Only four publications reported using GC based analyzers and PTR-MS (proton-transfer-reaction mass spectrometry) that allowed continuous VOC measurement. Because of this, the majority of experimental studies were only performed on limited numbers of air, manure, or dust samples. Many aerial VOCs had concentrations that were too low to be identified by the GC peaks.Although VOCs emitted from swine facilities have environmental concerns, only a few studies investigated VOC emission rates, which ranged from 3.0 to 176.5 mg d⁻¹ kg⁻¹ pig at swine finishing barns and from 2.3 to 45.2 g d⁻¹ m⁻² at manure storages. Similar to the other pollutants, spatial and temporal variations of aerial VOC concentrations and emissions existed and were significantly affected by manure management systems, barn structural designs, and ventilation rates.Scientific research in this area has been mainly driven by odor nuisance, instead of environment or health concerns. Compared with other aerial pollutants in animal agriculture, the current scientific knowledge about VOCs at swine facilities is still very limited and far from sufficient to develop reliable emission factors.     

吹脱捕集GC/FID法测定海河水中挥发性有机物

采用吹脱捕集GC/FID法对海河干流水中挥发性有机物进行定性、定量分析。共检测出 39种挥发性有机物 ,不同化合物的回收率为 84 2 %～ 143 2 % ,相对偏差为 1 5 %～ 9 6 %。当水样体积为 2 5mL时 ,方法检测限为 0 0 0 1μg/L～ 0 4μg/L。     

我国大气VOCs监测现状及挑战

对我国开展大气VOCs监测的必要性、监测现状以及主要使用的监测方法进行了分析。目前,我国已初步建立了大气VOCs手工与自动监测网络,主要采用预浓缩-热脱附-气相色谱-质谱/氢火焰离子化检测器法进行PAMS组分和TO-15组分分析,利用高效液相色谱法进行13种醛、酮类组分分析。目前大气VOCs监测还存在数据质量、灵敏度有待提高,不同设备或方法监测结果一致性较差等问题。为此在VOCs监测过程中应进一步加强质量保证与质量控制,并尝试通过提高预浓缩装置除水和干扰物效率、提升进样量等多种手段提高监测灵敏度。