聚丙烯酰胺浓度检测方法研究进展

综述了淀粉-碘化镉比色法、浊度法、凝胶色谱法、超滤浓缩薄膜干燥法、化学发光定氮法、氨电极法等6种检测HPAM浓度的技术,讨论了各种方法的测定原理、测定条件、技术参数、优缺点和最新研究进展等,可为研究与技术人员选用适宜的聚丙烯酰胺检测方法提供参考。     

两种测定氧化钙的方法对比

分别以钙试剂羧酸钠及钙黄绿素-酚酞作为指示剂测定矿石中CaO含量的方法对比。     

间接碘量法测定高锰酸钾溶液的浓度

采用稍少量的KMnO4进行溶液配制,探讨了间接碘量法标定KMnO4溶液浓度的原理和方法。此方法比Na2C2O4标定法操作简便,节约近半时间,结果较准确。     

Facile Method for Determining the Aspect Ratios of Mineral Dust Aerosol by Electron Microscopy

Mineral dust is the second largest atmospheric emission by mass and one of the least understood sources. The shape of the particles depends on their composition and has implications for particle optical properties and reactive surface area. Mineral dust particles are often approximated as spheroids to model their optical properties. In this study, scanning electron microscopy (SEM) is used to measure the aspect ratios of calcite, quartz, NX-illite, kaolinite (KGa-1b and KGa-2), and montmorillonite (STx-1b and SWy-2). In addition to traditional SEM images of the top of the particles, the SEM substrates are oriented approximately normal to the electron beam in order to image the side of the particles. In this manner, aspect ratios for the top and side orientation of the particles are determined. Calcite particles have an aspect ratio of approximately 1.3 in both orientations, while quartz particles have an aspect ratio of 1.38 in the top orientation and 1.64 in the side orientation. The clay minerals studied all exhibited plate-like structures with aspect ratios of 1.35 to 1.44 for the top orientation and 4.80 to 9.14 for the side orientation. These values are used to estimate the specific surface areas (SSAs) of the minerals, which are compared to Brunauer-Emmett-Teller (BET) surface area measurements. Through this study, we present a simple method for determining the aspect ratios of aerosolized samples, rather than relying on literature values of model systems. As a result, this technique should provide a better method for determining the optical properties of mineral dust particles.

Copyright 2014 American Association for Aerosol Research     

过滤常数确定方法的探讨

本文对现行三种确定过滤常的方法进行了方差分析和统计检验，结果表明，通常采用的微分法可能带来比较显著的误差，而不常用的积分法的误差最小。     

水硬度的测定方法

概述了水硬度的分析测定方法,主要介绍了EDTA络合滴定法,分光光度法,原子吸收法,ICP-AES法,离子色谱法,自动电位滴定法,离子选择性电极-流动技术法几种测定方法,对比了各种方法的优劣,并指出测定方法的发展方向。     

牛奶中掺入尿素的两种快速检测方法

建立了对二甲氨基苯甲醛法和亚硝酸盐-格里斯试剂法对牛奶中掺入尿素的快速检测方法。通过对显色剂剂量和酸度等反应条件的研究和选择，确定了两种方法的最佳实验条件。     

A Novel Optical Instrument for Estimating Size Segregated Aerosol Mass Concentration in Real Time

A novel optical instrument has been developed that estimates size segregated aerosol mass concentration (i.e., PM ₁₀ , PM ₄ , PM _2.5 , and PM ₁ ) over a wide concentration range (0.001–150 mg/m ³ ) in real time. This instrument combines photometric measurement of the particle cloud and optical sizing of single particles in a single optical system. The photometric signal is calibrated to approximate the PM _2.5 fraction of the particulate mass, the size range over which the photometric signal is most sensitive. The electrical pulse heights generated by light scattering from particles larger than 1 micron are calibrated to approximate the aerodynamic diameter of an aerosol of given physical properties, from which the aerosol mass distribution can be inferred. By combining the photometric and optical pulse measurements, this instrument can estimate aerosol mass concentrations higher than typical single particle counting instruments while providing size information and more accurate mass concentration information than traditional photometers. Experiments have shown that this instrument can be calibrated to measure aerosols with very different properties and yet achieve reasonable accuracy.     

A single-particle characterization of a mobile Versatile Aerosol Concentration Enrichment System for exposure studies

Background  

An Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to investigate the size and chemical composition of fine concentrated ambient particles (CAPs) in the size range 0.2–2.6 μm produced by a Versatile Aerosol Concentration Enrichment System (VACES) contained within the Mobile Ambient Particle Concentrator Exposure Laboratory (MAPCEL). The data were collected during a study of human exposure to CAPs, in Edinburgh (UK), in February-March 2004. The air flow prior to, and post, concentration in the VACES was sampled in turn into the ATOFMS, which provides simultaneous size and positive and negative mass spectral data on individual fine particles.     

分光光度法测定菠菜中铁含量的不确定度评定

目的:建立分光光度法测菠菜中铁的含量不确定度评定的数学模型。方法:根据JJF 1059.1-2012《测量不确定度评定与表示》,从测量过程各步骤分析不确定度来源,并对已识别来源的不确定度影响进行评价和分析。结果:测量菠菜中铁含量结果的不确定度主要来源于测量重复性、铁标准溶液、试样溶液的配置和试样的称量。当菠菜中铁含量为8.94 mg/kg时,其扩展不确定度为±0.14 mg/kg(k=2)。结论:该研究可为实验室评定蔬菜中铁含量的测定结果质量提供参考。     

Methods of Aerosol Measurement before the 1960s

ABSTRACT

The time period before the 1960s can be described as the classical age of aerosol science and aerosol measurement. The measurement philosophy during this period was different from that of the period after the 1960s. Particle number concentration was considered the most important parameter. Optical microscopy was the determinative procedure for sample evaluation, for particle counting, and for size measurement. The most frequently used sampling methods were impaction and impingement, thermal and electrostatic precipitation, and filtration. Condensation samplers, as well as manual condensation nuclei counters, were used also. Manual and simple light scattering and light absorption methods played an already important role. Ultramicroscopy and nephelometry were commonly used methods. Elutriators and aerosol centrifuges were used for determining aerodynamic particle sizes, particle shape factors, and mass size distributions. Chemical aerosol analysis was in a developing state. Silica, silicates, and heavy metals were the most often detected dust and aerosol components. Titration, colorimetry, photometry, and polarography were the most commonly used analytical procedures. Practically no automatic or computer-supported measurement or analytical equipment was available at this time. Sampling instruments often were made in the laboratory, rather than produced commercially.     

Coarse Aerosol Concentration Over the North Polar Waters of the Atlantic

This paper presents the data obtained during the polar research cruises of the r/v Oceania in 1995–2001. The aerosol size distributions were measured using the laser particle counter CSASP-100-HV-SP. The size spectral density between diameters 0.5–15 μ m was found to fit the following form: dN/dr = n(2 r) = exp (a2 r + b) , where: a = ? 0.29 and b are functions of wind speed. Additionally, poor precision of the sea spray emission determination using only the aerosol concentration data measured at one altitude was confirmed.     

提高水煤浆成浆浓度的几种方法

从煤质特性、粒度分布、水煤浆添加剂三个方面分析对水煤浆成浆浓度的影响。论述了提高水煤浆成浆浓度的几种常用方法,即合适的粒度分布、高效添加剂、制浆工艺与配煤技术。     

食品及饲料中三聚氰胺的检测方法

近年来,在食品和饲料中频频出现三聚氰胺,给食品安全带来了威胁,对食品和饲料中三聚氰胺的检测已成为必须。文章对国内外检测食品和饲料中三聚氰胺的分析方法进行了综述。     

Characterization of Indoor-Outdoor Aerosol Concentration Relationships during the Fresno PM Exposure Studies

Particle size distributions were measured indoors and outdoors of a single, detached residence during the Fresno particulate matter exposure studies in winter (February 1-28, 1999) and spring (April 18-May 16, 1999). Data was collected for particle sizes ranging from about 0.01 to 2.5     

阴离子表面活性剂(AS)的测定方法研究

阴离子表面活性剂(AS)能改变两相间的表面张力,具有润湿、起泡、洗涤的作用。阴离子表面活性剂(AS)随着生活废水排放到环境中会导致水质恶化,进而对水生生物和环境造成危害,阴离子表面活性剂已成为水体污染的监测指标之一。笔者介绍了近年来阴离子表面活性剂的测定方法,如共振光散射法、流动注射分析法、色谱法、紫外分光光度法、可见分光光度法、荧光光度法和联用法,并对今后阴离子表面活性剂检测方法的研究方向提出了建议。     

Condensation Particle Counters Combined with a Low-Pressure Impactor for Fast Measurement of Mode-Segregated Aerosol Number Concentration

An integrated airborne system comprising two condensation particle counters (CPCs, models 3771 and 3772, TSI Inc.) and a low-pressure impactor (LPI) has been developed (LPI-CPCs) for fast measurement of mode-segregated aerosol number concentration. The CPC 3771 is connected to the LPI to measure aerosol number concentrations below 0.17 μm in aerodynamic diameter, while the CPC 3772 directly measures the total aerosol number concentration. The former approximately corresponds to the Aitken mode fraction of the aerosol number concentration. The key concept is that the cutoff diameter of the LPI (aerodynamic diameter at which the transmission efficiency is 50%) is controlled by simultaneously modifying the pressure and flow rate through the LPI. The instrument was deployed onboard the King Air B200T aircraft during the Aerosol Radiative Forcing in East Asia (A-FORCE) conducted over the western Pacific in the spring of 2009. The results from the aircraft measurements, together with those from laboratory experiments, are used to demonstrate the in-flight performance of the instrument. We propose that fast airborne measurement of mode-segregated aerosols by LPI-CPCs is useful for a better understanding of the variability of aerosol number concentration in the troposphere.

Copyright 2013 American Association for Aerosol Research     

A Microscope-Based Particle Counting System for Determining Collected Aerosol Mass During the Calibration of a Cascade Impactor

It is shown that a simple optical particle-counting system can be efficiently and accurately used for determining the mass of collected particles during the calibration of a cascade impactor. For particles larger than 1 mu m in diameter, the limit of detection was enhanced by a factor 5 compared to the traditional spectrophotometer-based method.     

双子表面活性剂浓度的测量方法

双子表面活性剂是一类带有两个疏水链、两个亲水链和一个联接基团的化合物.两个亲水基通过联结基团靠化学键联接,由此使两个表面活性剂单体相当紧密地结合,联结基团的介入及其化学结构、联接位置的变化,使双子表面活性剂结构具有多样化,从而具有更优良的物理化学性质及界面活性.双子表面活性剂一般通过绘制表面张力随浓度的变化曲线来测定;还可根据稳态荧光探针法进行测定,但此种方法需要实验设备要求较高,所以通常选用测量表面张力值法来测量双子表面活性剂的浓度.