便携式GC-MS在有机气体应急监测中的优越性

结合应急监测的需要,针对在污染事故中对有机污染物难以快速定性、定量问题,分析了便携式GC-MS的性能特点,对应急监测仪器选用有着重要指导意义.     

酚二磺酸光度法和紫外分光光度法分析水中硝酸盐氮的比对

采用同一标准液和天然水样用酚二磺酸光度法和紫外分光光度法测定硝酸盐氮，进行比对分析，同时调查云南省内用此两种方法密码样考核的情况。得出紫外分光光度法操作简便、化学试剂污染小、获取数据及时，是值得推介的先进方法。     

水中硫化物测定方法的改进

对亚甲基蓝分光光度法测水中硫化物的预处理装置进行改进，改进后的装置操作较为简便，回收率达92％—99％。     

固相微萃取-便携式GC/MS快速测定水中痕量有机磷农药

采用固相微萃取-便携式气相色谱/质谱联用法（In situ SPME/GC-MS）分析地表水和废水中6种有机磷农药，通过优化测定条件，使6种有机磷农药在200 μg/L~500 μg/L范围内线性良好。方法检出限为033 μg/L～122 μg/L，低、高质量浓度标准溶液6次测定结果的RSD为68%~175%，加标回收率为849%~109%，与实验室方法的测定结果基本一致。     

便携式分光光度计在地表水环境应急监测中的适用性分析

考察了便携式分光光度计对地表水中化学需氧量(COD)、氨氮(NH_3-N)、氟化物(F~-)、总磷(TP)和六价铬(Cr~(6+))的应急监测的适用性。对方法精密度和准确度进行测定,并将便携式方法与实验室方法的测定结果进行比对。结果表明,方法精密度为2.3%~7.4%,标准样品除Cr6+外,其他均在保证值范围内;加标回收率为86.0%~110%,2种方法比对的相对偏差为2.9%~6.4%。该方法精密度与准确度良好,可以较好地应用于地表水环境应急监测中。     

Tailpipe emission characterizations of diesel-fueled forklifts under real-world operations using a portable emission measurement system

Non-road equipment is one of the key contributing sources to air pollution. Thus, an accurate development of emission inventory from non-road equipment is imperative for air quality management, especially for equipment with a large population such as diesel-fueled forklifts. The objective of this paper is to characterize duty-cycle based emissions from diesel-fueled forklifts using a portable emission measurement system (PEMS). Three duty-cycles were defined in this study, including idling, moving, and working (active duty operation) and used to characterize in-use emissions for diesel-fueled forklifts. A total of twelve diesel-fueled forklifts were selected for real-world emission measurements. Results showed that fuel-based emission factors appear to have smaller variability compared to time-based ones. For example, the time-based emission factors for CO, HC, NO, and PM_2.5 for forklifts were estimated to be 16.6–43.9, 5.3–15.1, 26.2–49.9, 5.5–11.1 g/hr with the fuel-based emission factors being 12.1–20.3, 4.1–8.3, 19.1–32.4, 3.5–6.5 g/kg-fuel, respectively. NO emissions appear to be the biggest concern for emissions control. Furthermore, most of the emissions factors estimated from this study are significantly different from those in both National Guideline for Emission Inventory Development for Non-Road Equipment in China and well-developed emission factor models such as NONROAD by US EPA. This implies that localized, preferably fuel-based emission factors should be adjusted based on real-world emission measurements in order to develop a representative emission inventory for non-road equipment.     

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.     

便携式GC-MS在应急监测中的应用

建立了便携式GC-MS测定空气和水体中挥发性有机物(VOCs)的方法,能快速、有效地对空气中37种和水体中54种挥发性有机物进行现场定性和定量。具有相关性好、检出限低、精密度好、准确度高的特点,适用于空气和水体中挥发性有机物的应急监测工作。     

便携式GC-MS快速测定水中苯胺

采用便携式GC-MS测定水体中的苯胺，并对水样中离子强度和顶空分析的平衡时间进行优化。试验表明，苯胺在10．0μg/L～200μg/L范围内有较好的线性，r为0．998；方法检出限为5．8μg/L；回收率为92．8％～96．7％；RSD为3．2％～8．6％。用54种VOCs混合标样对苯胺标液进行干扰试验，结果试验条件下苯胺与VOCs得到有效分离。     

便携式质谱仪应用于交通干线苯系物污染特征分析

介绍了EcoSys-P便携式质谱仪在无车日前后对交通干线环境空气中苯系物现场监测中的情况,同时该方法与经典的气相-质谱联机进行了对比试验,相对偏差≤25%,能够满足交通干线环境空气苯系物的现场监测要求.