空气中苯系物测定有关问题的探讨

对HJ 584–2010《环境空气苯系物的测定活性炭吸附/二硫化碳解吸–气相色谱法》和HJ 583–2010《环境空气苯系物的测定固体吸附/热脱附–气相色谱法》进行解析,结合监测工作实际情况,从采样、分析各个关键环节总结归纳了方法要点,提出了实际应用中的注意事项。为环保监测系统进行空气中苯系物测定方法的选择及正确应用提供借鉴。     

Determination of gas-liquid partition coefficients by automatic equilibrium headspace-gas chromatography utilizing the phase ratio variation method

Summary The new phase ratio variation method is described which represents a convenient way for the determination of gas-liquid partition coefficients for practical purposes, utilizing equilibrium headspace-gas chromatography (EHS-GC). This method is based on the relationship between reciprocal peak area and the phase ratio in the vial containing the sample solution; it involves regression analysis of the EHS-GC measurements of a number of sample vials containing the same sample solution but with a wide variation of phase ratios. Examples are given for both aqueous systems and systems consisting of a stationary (liquid) phase used as the solvent; comparison of the measured values with results obtained by other methods shows satisfactory agreement. A critical discussion of the conditions influencing the accuracy of the analytical results is given.Symbols which specifically refer to gas chromatography (GC), to equilibrium headspace sampling (EHS) and to EHS-GC are marked by the corresponding acronym.     

Novel Sampling for the Determination of Naphthalene in Air by Gas Chromatography–Mass Spectrometry

Here are reported two new sampling method approaches for the determination of naphthalene in ambient air for concentrations from 0.25 to 18.7?µg/L. The first method used for gas phase naphthalene analysis produced an average recovery of 88.8% and the second method using headspace sampling produced an average recovery of 93.8%. The second method showed better recovery than the former, so it was used for subsequent comparative gas-phase determination of naphthalene. The second method was validated at various naphthalene concentrations and humidity using a naphthalene gas generator to produce various naphthalene standards and a naphthalene-monitoring instrument. The naphthalene concentrations generated using the gas generator and determined second sampling method with gas chromatography–mass spectrometry (GC–MS) were compared to the sensor measurements and were in good agreement. In summary, the sampling methods presented provided reliable gas-phase naphthalene determination when coupled with GC–MS.     

茶多酚的色谱分析法

 对茶多酚的主要成分――儿茶素的色谱分析法进行了综述。重点介绍了应用最多的反相高 效液相色谱法,同时简述了平板色谱法、气相色谱法以及目前出现的新的色谱分析方法。     

离子色谱法在城市和背景区域SO2监测中的应用

介绍用无动力采样技术采集样品、离子色谱法分析SO2污染物浓度的监测方法。国际实验室间分析结果的比对实验表明，离子色谱法具有快捷、准确及自动化程度较高等优点。该方法在城市和背景区域环境空气背景值研究，如SO2污染物迁移规律、空气质量预测预报模型验证及远距离传输等方面具有很大的实用价值。     

氨基酸分析方法的研究进展

对目前应用于氨基酸分析的主要方法作了较详细评述。这些方法包括柱后衍生高效阳离子交换色谱法、柱前衍生反相高效液相色谱法、高效阴离子交换色谱-积分脉冲安培检测法等。引用文献73篇。     

氢气的分析方法研究

介绍了低纯度氢气和高纯度氢气的不同分析检测方法。对于纯度小于99.99%的氢气,其分析方法主要有爆炸法、吸收法、膜分离法和气相色谱法;对于纯度大于99.99%的氢气,其分析方法主要有变温浓缩的热导池气相色谱法、配有光电离子化检测器(DID)的气相色谱法和色谱-质谱联用法。     

Exploiting the versatility of vacuum‐assisted headspace solid‐phase microextraction in combination with the selectivity of ionic liquid‐based GC stationary phases to discriminate Boswellia spp. resins through their volatile and semivolatile fractions

The frankincense resins, secreted from Boswellia species, are an uncommon example of a natural raw material where every class of terpenoids is present in similar proportions. Diterpenoids (serratol, incensole, and incensole acetate) are used to discriminate samples from different species and origins. Headspace solid‐phase microextraction has been used for frankincense analysis, although it requires long sampling time for medium‐ to low‐volatility markers; headspace solid‐phase microextraction under vacuum can overcome this limit. Gas chromatography is used for analysis but the separation of incensole and serratol needs polar stationary phases. In this study, we develop a method to discriminate frankincenses based on vacuum‐assisted headspace solid‐phase microextraction combined with fast gas chromatography‐mass spectrometry with ionic liquid–based stationary phases. The optimized conditions for solid samples were: air evacuation below 0°C, 15 min of incubation time, and 15 min of extraction time. Losses of volatiles due to vial air‐evacuation in the presence of the sample were minimized by sample amount above 100 mg and low sample temperature. Fast gas chromatography provides the baseline separation of all markers in 20 min. By applying vacuum sampling and fast gas chromatography, the total analysis was reduced to 50 min compared to 120 min (60 min sampling plus 60 min analysis) as previously reported. The method was successfully applied to commercial frankincense samples.     

顶空-毛细管气相色谱法预测变压器潜伏性故障的初步探讨

本文选用自动顶空毛细管气相色谱分流进样体系对多种空白变压器油、正常变压器油及故障变压器油进行了分析,探讨用这种方法对变压器故障判断的可能性。     

Novel techniques for enhancing sensitivity in static headspace extraction-gas chromatography

Static headspace extraction-gas chromatography (SHE-GC) is one of the most commonly used techniques for the analysis of volatile compounds. It is considered by most to be a mature technique and to an extent this is true: there are many users from outside the traditional chromatography research community developing and publishing SHE-GC methods and there are numerous instruments and devices for SHE-GC commercially available. However, research on new SHE-GC methods continues. In this review, several interesting new developments in SHE-GC are described using examples from the past three years’ literature. First, the fundamental theory of SHE-GC is reviewed to provide a basis and common theme for the discussion of new methods. Next, several areas of SHE-GC research are explored: new sampling configurations, analyte derivatization and ionic liquids as solvents. These are all means for enhancing partitioning of the analyte into the vapor phase, thus improving analytical sensitivity of the overall SHE-GC method. Ideally, partitioning of analytes into the vapor phase is increased while partitioning of matrix components is not, or is decreased. There are many aspects of the seemingly straightforward process in SHE-GC that require further fundamental research to extend the application range of SHE-GC and to make method development more systematic.     

Chromatographic Techniques for the Determination of Free Phenol in Foundry Resins

Phenol is a toxic compound present in a wide variety of foundry resins. Its quantification is important for the characterization of the resins as well as for the evaluation of free contaminants present in foundry wastes. Two chromatographic methods, liquid chromatography with ultraviolet detection (LC-UV) and gas chromatography with flame ionization detection (GC-FID), for the analysis of free phenol in several foundry resins, after a simple extraction procedure (30 min), were developed. Both chromatographic methods were suitable for the determination of phenol in the studied furanic and phenolic resins, showing good selectivity, accuracy (recovery 99–100%; relative deviations <5%), and precision (coefficients of variation <6%). The used ASTM reference method was only found to be useful in the analysis of phenolic resins, while the LC and GC methods were applicable for all the studied resins. The developed methods reduce the time of analysis from 3.5 hours to about 30 min and can readily be used in routine quality control laboratories.     

Thin-layer chromatography/electrospray ionization triple-quadrupole linear ion trap mass spectrometry system: analysis of rhodamine dyes separated on reversed-phase C8 plates

The direct analysis of separated rhodamine dyes on reversed-phase C(8) thin-layer chromatography plates using a surface sampling/electrospray emitter probe coupled with a triple-quadrupole linear ion trap mass spectrometer is presented. This report represents continuing work to advance the performance metrics and utility of this basic surface sampling electrospray mass spectrometry system for the analysis of thin-layer chromatography plates. Experimental results examining the role of sampling probe spray end configuration on liquid aspiration rate and gas-phase ion signal generated are discussed. The detection figures-of-merit afforded by full-scan, automated product ion and selected reaction monitoring modes of operation were examined. The effect of different eluting solvents on mass spectrum signal levels with the reversed-phase C(8) plate was investigated. The combined effect of eluting solvent flow-rate and development lane surface scan rate on preservation of chromatographic resolution was also studied. Analysis of chromatographically separated red pen ink extracts from eight different pens using selected reaction monitoring demonstrated the potential of this surface sampling electrospray mass spectrometry system for targeted compound analysis with real samples.     

离子色谱中的安培检测方法及其应用

介绍了离子色谱中的安培检测方法(包括恒电位安培检测法、脉冲安培检测法和积分脉冲安培检测法)的原理和应用。脉冲安培检测法与高效阴离子交换色谱结合(HPAEC-PAD)是一种新的分析糖类化合物的方法;积分脉冲安培检测法与高效阴离子交换色谱结合(HPAEC-IPAD)是一种新的氨基酸分析方法。     

Analysis of enhanced oil recovery formulations

Summary Methods for the determination of low levels of surfactants in produced oil field brines have been developed. Alkylbenzene sulfonates (ABS) and alkylether sulfates can be quantified at very low levels by high-performance liquid chromatography (HPLC) and mobile-phase ion chromatography (MPIC), respectively. These methods proved to be rapid, selective, and gave results in excellent agreement with traditional low-phase titration techniques. Although this paper records the use of these methods for analysis of oil field produced fluids, they should be easily adaptable to other situations wherein the analysis of these two classes of surfactants is required.     

Determination of polychlorinated biphenyls in ambient air by gas chromatography coupled to triple quadrupole tandem mass spectrometry

A multiresidue method for determining 22 polychlorinated biphenyls (PCBs) in air has been developed and validated by gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS) using a triple quadrupole analyzer (QqQ). The method was validated in terms of both steps of sampling and analysis. The sampling method, which is based on active sampling using polyurethane foam (PUF) as adsorbent, was validated by generating standard atmospheres. The retention capacity of this sampling sorbent allows up to 5 m³ of air to be sampled without any breakthrough for most compounds. Two solvent extraction methods were compared: sonication and Soxhlet extraction with a mixture of n-hexane:diethyl ether (95:5 v/v). Both extraction methods yielded similar results, but the first one required less solvent and time. The method exhibited good accuracy (80.3–99.8%), precision (2.2–15.2%) and lower limits that allowed quantification and confirmation at levels as low as 0.008 ng/m³. Finally, the method was applied to the analysis of PCBs in the air in areas near to a municipal solid-waste landfill and directly above the refuse in the landfill, where it indicatedd the presence of some of the target compounds. Figure General chemical structure of polychlorinated biphenyls     

Evaluation of different two‐dimensional chromatographic techniques for proteomic analysis of mouse cardiac tissue

In proteomics experiments the first critical step after sampling is certainly sample preparation. Multidimensional chromatography techniques have emerged as a powerful tool for the large‐scale analysis of such complex samples as biological samples. In order to evaluate these separation techniques, microgram quantities of protein extracted from mouse heart tissue were fractionated by four different chromatographic methods. Regarding peptide‐level fractionation, the first dimension of separation was performed with high‐pH reversed‐phase chromatography (pH‐RP) and strong cation exchange chromatography (SCX). Regarding protein‐level fractionation, C₈ protein reversed‐phase (C₈‐RP Prot) and high‐recovery protein reversed‐phase (hr‐RP Prot) were used instead. The second dimension consisted of a reversed‐phase nano‐HPLC on‐Chip coupled to an electrospray ionization quadrupole time‐of‐flight mass spectrometer for tandem mass spectrometric analysis. The performance and relative fractionation efficiencies of each technique were assessed by comparing the total number of proteins identified by each method. The peptide‐level pH‐RP and the hr‐RP Prot protein‐level separations were the best methods, identifying 1338 and 1303 proteins, respectively. The peptide‐level SCX, with 509 proteins identified, was the worst method. Copyright © 2010 John Wiley & Sons, Ltd.     

Rapid on-line analysis of low molecular weight hydrocarbons using glass capillary gas chromatography

Rapid analysis is important for on-line chromatography. Gaseous or vaporized samples have been injected via heated gas sampling valves of less than 500 μl dead volume. The critical sampling and split problems could be solved by temperature programming. The general analysis described could be successfully used inter alia in scouting reactions.     

Quantitative analysis of the compounds in synthesis mixtures of 2,2-dimethyl-3-hydroxypropionaldehyde by RP-HPLC and GC

Summary RP-HPLC and GC methods are described for the determination of the compounds in synthesis mixtures of 2,2-dimethyl-3-hydroxypropionaldehyde (DHPAL). Special attention is paid to the analysis of DHPAL. Conditions for analysis are developed so that no derivatization is needed despite the equilibrium reactions typical of hydroxy aldehydes. Different solvent matrices, pH and sample concentrations are tested in sampling and analysis. Linearity of the calibration lines and precision of the methods are evaluated for all compounds. Detection limits of different compounds are calculated for both methods.     

色谱技术在药物-血浆蛋白相互作用研究中的应用进展

小分子药物进入人体血液循环系统后与人血清白蛋白(HSA)、α₁ -酸性糖蛋白(AGP)等血浆蛋白存在广泛的相互作用,这些相互作用深刻影响药物在体内的分布及其与靶标蛋白的结合,进而影响药物效应的发挥。深入探究药物与血浆蛋白间的相互作用对于候选药物的成药性优化、新药研发、联合用药的风险评控等意义重大。而发展高效、灵敏、准确的分析检测方法是开展药物-血浆蛋白相互作用研究的关键。近年来,色谱技术由于其高通量、高分离性能、高灵敏度等特点在该领域得到了广泛的应用,包括测定血浆蛋白翻译后修饰对药物结合的影响,多种药物的竞争性结合等。其中,高效亲和色谱(HPAC)和毛细管电泳(CE)应用最为广泛,能够通过多种分析方法获取结合常数、结合位点数、解离速率常数等相互作用信息。该文着重综述了HPAC和CE在药物-血浆蛋白相互作用研究中的常用策略及最新研究进展,包括HPAC中常用的前沿色谱法、竞争洗脱法、超快亲和提取法、峰值分析法和峰衰减分析法,以及CE中常用的亲和毛细管电泳法(ACE)和毛细管电泳前沿分析法(CE-FA)等。最后,该文还对当前色谱方法存在的不足进行了总结,并对色谱技术在药物-血浆蛋白相互作用研究领域的应用前景和发展方向进行了展望。