荧光光度法测定室内空气中的甲醛

针对室内空气中低浓度甲醛的测定,在不增加采样流量和采样时间的情况下,本文利用荧光光度法很好地测定了室内空气中低浓度的甲醛,试验证明该方法具有灵敏度高,检出限低,精密度和准确度好的特点。     

荧光光度法测定室内空气中的甲醛

针对室内空气中低浓度甲醛的测定,在不增加采样流量和采样时间的情况下,本文利用荧光光度法很好地测定了室内空气中低浓度的甲醛,试验证明该方法具有灵敏度高,检出限低,精密度和准确度好的特点。     

荧光光度法测定室内空气中的甲醛

针对室内空气中低浓度甲醛的测定,在不增加采样流量和采样时间的情况下,本文利用荧光光度法很好地测定了室内空气中低浓度的甲醛,试验证明该方法具有灵敏度高,检出限低,精密度和准确度好的特点.     

室内空气中VOC全采样多项快速检测技术研究

采用硅烷化处理内壁的不锈钢采样罐采集室内空气样品,三级冷阱预浓缩,气相色谱-质谱仪联用分析室内空气中挥发性有机物(VOC)。选取100、50、25、10、52、ppb浓度点VOC标准气体绘制标准曲线,曲线的线性相关系数R≥0.99,每个浓度点重复测定的相对标准偏差RSD<5%(n=6),平均相对标准偏差MRSD<5%(n=6)。现场采样分析结果,平行样测定结果之差与平均值比较的相对偏差<10%。本检测方法的扩展不确定度10.6%。方法可实现对现场挥发性有机气体的全采样、全分析,避免了因吸附剂的选择吸附性所引起的采样、分析误差。     

室内空气中甲醛检测及去除方法分析

针对人们对室内空气中甲醛危害的关注问题,本文分析并总结了国家及行业标准中对室内空气中甲醛的限量及检测方法。同时分析当前文献研究中对甲醛去除的方法,主要分为吸附法、催化氧化法、生物降解法,进一步探讨甲醛检测和去除方法的进展及方向。     

室内空气中甲醛的概述

介绍甲醛的理化性质、室内空气中甲醛的主要来源及甲醛对人体的危害,并简要概述室内空气中甲醛的检测方法。     

Interscan 4160型甲醛分析仪测定室内空气中甲醛浓度不确定度的评定

采用Interscan 4160型甲醛分析仪测定室内空气中甲醛浓度，对测量结果的不确定度影响因素进行了分析，并对各不确定度分量和测量结果的不确定度进行了评定。     

甲醛气体传感器研究进展

甲醛是室内空气的主要污染物之一，随着人们对室内空气污染的日益关注，对甲醛的准确及时检测显得更加重要。目前检测甲醛气体最为快速的方法就是传感器法。在综合分析了国内外甲醛气体传感器的研究现状的基础上，着重就测定甲醛的电化学传感器、基于化学发光的传感器、金属氧化物传感器、电子鼻、声表面波传感器的特性进行了阐述与剖析，指出了甲醛气体传感器存在的问题，并预测了其发展趋势。     

甲醛快速测定仪测试性能研究

通过考察甲醛快速测定仪分析方法的线性范围、灵敏度、准确度、精密度及方法扩展不确定度等技术指标，研究环境因素如空气中干扰物、温度、湿度、风速等的影响，比较甲醛快速测定仪与国家标准方法在测试甲醛标准气体或室内空气测试结果的差异。结果证实甲醛快速测定仪分析方法的特性优异、测试结果受环境因素影响小与国家标准方法测试结果相关性好，适合测试室内空气中的甲醛气体。     

室内甲醛污染控制效果的探讨

针对室内空气中甲醛污染的现状,本文分析了控制室内小气候、建材甲醛的去除和室内空气净化对甲醛污染的控制效果,认为可以通过高温烘赶、加强通风、人造板中的甲醛去除和各种净化空气措施来减少室内甲醛污染。     

Absorption of lean formaldehyde from air with Na2SO3 solution

Formaldehyde is a major indoor pollutant over the world and its high release over the national standards in developing countries, such as China, harms people's health seriously. In this work, an investigation is carried out in a stirred vessel with a plain gas-liquid interface for the absorption of lean formaldehyde from pollution air by Na(2)SO(3) solution at 25 degrees C. Experiments are conducted with Na(2)SO(3) concentrations of 0.01-0.30kmolm(-3). The results show that the Na(2)SO(3) solution is an effective absorbent to remove lean formaldehyde from polluted air. The experiments reveal that the absorption rate is considerably influenced by the gas flow rate and formaldehyde concentration. The Na(2)SO(3) concentration has little effect on the absorption rate, and the loading content of formaldehyde reduces the absorption rate only if the formaldehyde concentration approaches or exceeds the concentration of Na(2)SO(3) solution. A theoretical model is developed and used to successfully calculate the absorption rate with the overall relative deviation of less than 15% to the experimental data. A possible process of the absorption method is also proposed in this paper. The analysis shows that the proposed process is feasible in removing formaldehyde from indoor air.     

Development of a compound-specific carbon isotope analysis method for atmospheric formaldehyde via NaHSO3 and cysteamine derivatization

A novel method has been developed for the compound-specific carbon isotope analysis of atmospheric formaldehyde using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The method allows the determination of the delta13C value for atmospheric formaldehyde at nanogram levels with higher precision and lower detection limit. In the present work, atmospheric formaldehyde was collected using NaHSO3-coated Sep-Pak silica gel cartridges, washed out by water, then derivatized by cysteamine of known delta13C value, and the delta13C value of its derivative (thiazolidine) determined by GC/C/IRMS. Finally, the delta13C value of atmospheric formaldehyde could be calculated by a simple mass balance equation between formaldehyde, cysteamine, and thiazolidine. Using three formaldehydes with different delta13C values, calibration experiments were carried out over large ranges of formaldehyde concentrations. The carbon isotope analysis method achieved excellent reproducibility and high accuracy. There was no carbon isotopic fractionation throughout the derivatization processes. The differences in the carbon isotopic compositions of thiazolidine between the measured and predicted values were always <0.5 per thousand, within the specifications of the GC/C/IRMS system. The present method was also compared with the previous 2,4-dinitrophenylhydrazine derivatization method, and this method could be performed with lower analytical error and detection limit. Using this method, four 6-h ambient atmospheric formaldehyde samples were consecutively collected from 8 to 9 March 2005. The results showed that the delta13C values of atmospheric formaldehyde were different during the daytime and nighttime. This method proved suitable for the routine operation and may provide additional insight on sources and sinks of atmospheric formaldehyde.     

Formaldehyde removal by potted plant-soil systems

Formaldehyde is a major indoor air pollutant. Formaldehyde removal from indoor air conduces to decrease the health risk for urban inhabitants. In this study, a dynamic chamber technique was employed to investigate formaldehyde removal by potted spider plant (Chlorphytum comosum), aloe (Aloe vera) and golden pothos (Epipremnum aureum) with potted soils. The results showed that the potted plant-soil systems could remove formaldehyde from air in a long time. The spider plant-soil system had the highest formaldehyde removal capacity compared with others. Higher metabolisms in plants and microorganisms in daytime may give a reasonable explanation for higher formaldehyde removal capacities for plant-soil systems in daytime. The order of formaldehyde removal capacity for the three plant species agreed well with the sequence of formaldehyde dehydrogenase activities from plant leaves. Formaldehyde removal by plant may be diffusion-limited rather than reaction-limited since the detached formaldehyde dehydrogenase activities from the leaves of the three plant species were higher than in vivo metabolic capacities. Formaldehyde in air can be largely absorbed and metabolized by the microorganisms in the potted soils indicating that further elevating formaldehyde removal capacity for plant-soil system will be realized by increasing exposed surface of potted soil.     

Isotopic analysis of atmospheric formaldehyde by gas chromatography isotope ratio mass spectrometry

Little is known about the isotopic composition of formaldehyde in the atmosphere, a chemical intermediate in hydrocarbon oxidation. Here, we present a promising new method to analyze the carbon (delta 13C) and hydrogen (delta D) isotopic composition of atmospheric formaldehyde. The direct isotopic analytical technique described uses continuous-flow gas chromatography-isotope ratio mass spectrometry, which provides flexibility for either isotopic analysis without correction for derivative functional groups. Current levels of precision of measurement are +/-1.1 and +/-50 per thousand (1 sigma) for delta 13C and delta D analyses, respectively. Concentration of formaldehyde in ambient air is also determined, coincident with isotopic measurement, to a precision of +/-15%. The method has the required sensitivity for analyses of formaldehyde in urban air on relatively small volume grab samples of whole air (10-70L STP), potentially providing high temporal resolution. This is particularly advantageous for studying formaldehyde given its short lifetime and large variability in the atmosphere.     

Feasibility of collection and analysis of airborne carbonyls by on-sorbent derivatization and thermal desorption

The most commonly used method for analysis of airborne carbonyls is to collect the analytes on solid sorbents coated with a suitable derivatization agent, followed by solvent desorption and liquid injection for analysis by high-pressure liquid chromatography. We have explored a new approach by combining on-sorbent derivatization and thermal desorption to measure airborne carbonyls. More specifically, carbonyls in the air are collected onto an O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA)-coated Tenax sorbent packed in a tube with dimensions identical to those of a gas chromatography (GC) injector liner. The derivatives are then released by in-injection port thermal desorption to a GC column for analysis. Gaseous carbonyls, including formaldehyde, acetaldehyde, benzaldehyde, glyoxal, and methylglyoxal, at ppbv levels are shown to be effectively collected (> or = 92% collection efficiency) onto the sampling tubes at a flow rate of 20 mL/min under both < 1% and 71% relative humidity. The collection efficiency drops as the sampling flow rate increases, and the degree of decrease is compound dependent. The derivatization agent, at a level of approximately 127 nmol/tube, is thermally desorbed and eluted from the GC column without compromising the determination of any carbonyl-PFBHA derivatives. Detection limits of low ppbv to sub-ppbv are achieved for a sample air volume of 4.8 L. Using this new method, we have measured formaldehyde, acetaldehyde, benzaldehyde, glyoxal, and methylglyoxal to be 4.9-16.3, 0.6-8.2, <5.9, 0.5-4.1, and <2.4 ppbv, respectively, in the ambient atmosphere at the university bus stop. This method is less labor intensive than the solvent desorption technique and avoids use of organic solvents. Other classes of airborne polar species can be measured through the same approach by selecting an appropriate derivatization agent.     

负离子空气净化灯对室内空气中甲醛的治理作用

为有效解决室内空气中甲醛治理问题,采用模拟室内环境污染状况,通过负离子空气净化灯在开灯前后室内空气中甲醛含量变化的实验方法进行论证,得出负离子空气净化灯在开灯后,能产生大量的负氧离子,对净化空气质量,特别是降低空气中的甲醛含量,有较好的治理效果,对改善人类生活环境有积极的作用。     

An application of artificial neural networks for modeling formaldehyde emission based on process parameters in particleboard manufacturing process

Volatile organic compounds refer to a large class of carbon-based chemicals capable of evaporating easily into the air at room temperature. Formaldehyde is one of the best known volatile organic compounds, and long-term exposure to formaldehyde emission from wood-based building products in indoor air may cause many adverse health effects. This paper presents an implementation of artificial neural networks for modeling the formaldehyde emission from particleboard as a wood-based product based on wood-glue moisture content, density of board and pressing temperature, with the experimental data collected from Petinarakis and Kavvouras (Wood Res 51(1):31–40, 2006). With the constructed model, formaldehyde emission of particleboard could be predicted successfully, and the intermediate formaldehyde emission values not obtained from experimental investigation could be predicted for different combinations of manufacturing parameters. The results proved that the artificial neural network is a promising technique in predicting the formaldehyde emission from particleboard. In this regard, the findings of this study will help the manufacturing industries in obtaining the intermediate values of the formaldehyde emission without performing further experimental activity. The model thus may save time, reduce the consumption of experimental materials and design costs.     

棕纤维弹性床垫甲醛释放量测定方法的研究

采用干燥器法、气候箱法、气体分析法对棕纤维弹性床垫中的甲醛进行收集,并用酚试剂分光光度法对收集的甲醛进行检测。检测结果表明,不同方法收集的棕纤维弹性床垫甲醛释放量具有一定的相关性,不同收集方法间呈线性关系。