Using solid-phase microextraction combined with gas chromatography-mass spectrometry for the study of the volatile products of biosynthesis released by plants and microorganisms

Published data on the methods and results of study of profiles of volatile biologically active compounds are summarized and discussed. The leading role of gas chromatography-mass spectrometry combined with headspace solid-phase microextraction as an optimum analytical method for determining the qualitative and quantitative composition of volatile organic compounds in in vivo experiments is substantiated. The results of investigation of volatile organic compounds produced by micromycetes of the genus Fusarium are reviewed.     

Application of Head-Space Analysis with Passive Adsorption for Forensic Purposes in the Automated Thermal Desorption-Gas Chromatography-Mass Spectrometry System

Offenders often use petroleum products as accelerants to commit an arson. A multi-component mixture of organic compounds isolated from the fire debris significantly differs from the initial one. These changes result from many factors, i.e. evaporation of the volatile components or presence of some organic compounds in the sample, which do not originate from the petroleum product (e.g. extinguishing medium components, products of pyrolysis of the burned material). The aim of presented research was to evaluate the influence of these factors. A series of experiments were carried out, and the analytical procedure was worked out. The headspace analysis with passive adsorption or the liquid extraction with ultrasonification was used for separation and concentration of the analytes. The mixture of organic compounds (accelerants, pollutants) was identified by the use of gas chromatography hyphenated with mass spectrometry. Principal component analysis (PCA) and likelihood ratio approach (LR) were applied to distinguish between evaporated samples of kerosene and diesel fuel. The elaborated procedure was verified both, witch inter-laboratory tests and using it for examinations of simulated fire debris.     

Determination of trace elements in seawater and river water by atomic absorption spectrometry with the use of an electrothermal crucible atomizer with two evaporation zones for solid samples

Direct and sorption-atomic absorption spectrometric determination methods were developed for dissolved and suspended Cd, Pb, and Tl species in seawater and river water were developed. These methods involve the step of ashing solid matrices (suspension or suspension + concentrate) in the crucible-rod system followed by the simultaneous atomization of a thermally modified sample and a condensate of volatile components. A crucible-cell-rod three-chamber graphite electrothermal atomizer with two evaporation zones and a common isothermal analytical zone, which were heated independently, was proposed for the analysis of these matrices. The approach proposed improved the metrological characteristics of the results of determining volatile metals in samples with high organic matter contents.     

Development of a solid-phase microextraction method with micellar desorption for the determination of chlorophenols in water samples. Comparison with conventional solid-phase microextraction method

A novel analytical method is presented for the determination of chlorophenols in water. This method involves pre-concentration by solid-phase microextraction (SPME) and an external desorption using a micellar medium as desorbing agent. Final analysis of the selected chlorophenols compounds was carried out by high-performance liquid chromatography (HPLC) with diode array detection (DAD). Optimum conditions for desorption, using the non-ionic surfactant polyoxyethylene 10 lauryl ether (POLE), such as surfactant concentration and time were studied. A satisfactory reproducibility for the extraction of target compounds, between 6 and 15%, was obtained, and detection limits were in the range of 1.1-5.9ngmL(-1). The developed method is evaluated and compared with the conventional one using organic solvent as a desorbing agent. The method was successfully applied to the determination of chlorophenols in water samples from different origin. This study has demonstrated that solid-phase microextraction with micellar desorption (SPME-MD) can be used as an alternative to conventional SPME method for the extraction of chlorophenols in water samples.     

Complexation as the most important factor in the fate and transport of heavy metals in the Dnieper water bodies

The results of long-term investigations of the concentrations of dissolved forms of some heavy metals (Mn, Cu, Zn, Pb, Cr, Cd) and their species in the water of the Dnieper reservoirs and the Dnieper-Bug estuary are considered. Chemiluminescent methods, anodic stripping voltammetry, membrane filtration, ion-exchange, and gel-permeation chromatography were used for study of the speciation of the metals. It has been found that binding of heavy metals into complexes with dissolved organic matter (DOM) is the dominant factor of their stabilization in solution. The molecular weight distribution of organic metal complexes and their chemical nature, as well as the potential complexing ability of DOM were investigated. Humic substances, particularly fulvic acids, play a major role in the complexation. These ligands bind from 45 to 80% of metals in the form of organic complexes. Metal complex compounds of relatively low molecular weight (<5 kDa) predominated in the organic complexes.     

Optimization of analytical quality control for long-term monitoring of metals and volatile organic compounds in groundwater

Statistical analysis of historical results for matrix spikes (MS), matrix spike duplicates (MSD), and laboratory control samples (LCS) from aqueous samples analyzed for metals and volatile organic compounds was performed to determine whether the MS/MSD provided substantive information apart from that provided by the LCS. The statistical analysis showed that the mean recovery of all analytes from MS/MSD closely approximated the mean recovery of all analytes from the LCS. Average bias, skewness, and kurtosis were also assessed for both data sets. The evaluation provided strong evidence for the use of LCS recoveries as performance indicators of probable MS/MSD recoveries of metals and volatile organic compounds from groundwater.     

Determination of VOC and TVOC in Air Using Thermal Desorption GC-MS – Practical Implications for Test Chamber Experiments

The determination of volatile organic compounds (VOC) species and concentrations are important for the evaluation of indoor air quality. Numerous methods exist for the determination of levels of both VOC and TVOC (total volatile organic compounds). These include the use of direct-reading instruments as well as gas chromatographic techniques. The benefits and drawbacks of the various methods are well known, and none provide precise measurement of the complex VOC mixtures that constitute TVOC in indoor air. A specific approach for TVOC measurement has been proposed in Europe in ECA-report no.19 to overcome these shortcomings. On this basis a practical analytical method was developed and applied to emission test chamber studies. Special focus was required on compounds of high volatility and the preparation of calibration standards.     

Analysis of volatile organic compounds in indoor environments using thermal desorption with comprehensive two‐dimensional gas chromatography and high‐resolution time‐of‐flight mass spectrometry

Building‐related health effects are frequently observed. Several factors have been listed as possible causes including temperature, humidity, light conditions, presence of particulate matter, and microorganisms or volatile organic compounds. To be able to link exposure to specific volatile organic compounds to building‐related health effects, powerful and comprehensive analytical methods are required. For this purpose, we developed an active air sampling method that utilizes dual‐bed tubes loaded with TENAX‐TA and Carboxen‐1000 adsorbents to sample two parallel air samples of 4 L each. For the comprehensive volatile organic compounds analysis, an automated thermal desorption comprehensive two‐dimensional gas chromatography high‐resolution time‐of‐flight mass spectrometry method was developed and used. It allowed targeted analysis of approximately 90 known volatile organic compounds with relative standard deviations below 25% for the vast majority of target volatile organic compounds. It also allowed semiquantification (no matching standards) of numerous nontarget air contaminants using the same data set. The nontarget analysis workflow included peak finding, background elimination, feature alignment, detection frequency filtering, and tentative identification. Application of the workflow to air samples from 68 indoor environments at a large hospital complex resulted in a comprehensive volatile organic compound characterization, including 178 single compounds and 13 hydrocarbon groups.     

Examination of non-volatile organic compounds in red wines made in Eger

At present the analytical investigation of human consumption products, with special regard to the environmental and health connections, is basically important all over the world. Recently in several countries it was almost impossible to sell wine without a certificate of quality, based on modern, instrumental analytical methods. There is well-known medical–biological evidence, which has proved the antioxidant and vein wall-protecting effects of the wines in the case of frugal ingestion. On the other hand, they also play a part in the prevention of heart attacks. Regarding these biological effects the most important constituents of wines are the flavonoids, anthocyanidins, and their glycosides. Anthocyanins can be identified first of all in red wines. The organic constituents have characteristic antioxidant effects, which can play an important role in health protection. During our investigation we have studied the volatile and non-volatile organic compounds in different types of wines made in Eger and Tokay (Hungary). In our opinion these types of research projects have unique importance, from the economic viewpoint and in that they are not negligible in a national context. The separation and determination of volatile compounds was carried out by applying a Finnigan GSQ GC-MS apparatus and the non-volatile ones with HPLC-DAD and FAB MS techniques.     

Preparation of iron,aluminium, calcium,magnesium, and zinc humates for environmental applications

A few non-conventional humate sorbents, i.e. iron humate (FeH), aluminium humate (AlH), calcium humate (CaH), magnesium humate (MgH), and zinc humate (ZnH), were prepared from a commercial product Fortehum L/K (Humatex, Bílina, Czech Republic). The metal content in humates was determined by X-ray fluorescence analysis, the organic elements (C, H, N, and S) were analysed by an Elementar Vario III and the functional groups were determined by classical methods using KBr pellets and diffuse reflection infrared spectroscopy (DRIFTS). FeH, AlH, and ZnH were tested as sorbents for the removal of inorganic or organic pollutants (metals, inorganic ions, dyes, and chlorophenols) from waste water. Sorption properties decreased in order: ZnH, AlH, FeH. CaH and MgH are partly soluble and therefore they are not usable as sorbents. However, their ion-exchange abilities for heavy metals are excellent which makes them usable for phytoremediation and bioremediation.     

Comparison of different methods for the determination of volatile organic compounds in water samples

The aim of this work was to compare the characteristics of three methods, membrane inlet mass spectrometry (MIMS), purge-and-trap gas chromatography-mass spectrometry (P&T) and static headspace gas chromatography (HSGC), for the determination of volatile organic compounds in water samples as used in routine analysis. The characteristics examined included linear dynamic ranges, detection limits of selected environmentally hazardous volatile organic compounds (e.g. toluene, benzene and trichloroethene) in water, required analysis time and reproducibility of the analytical methods. The MIMS and P&T methods had the lowest detection limits for all the tested compounds, ranging from 0.1 to 5 mug 1(-1). Linear dynamic ranges using the MIMS method were about four orders of magnitude and using the P&T method about two orders of magnitude. Detection limits of the HSGC method were 10-100 times higher than those of the other two methods, but the linear dynamic ranges were larger, even up to six orders of magnitude. The analysis time per sample was shortest for the MIMS method, from 5 to 10 min, and ranged around from 35 to 45 min for the HSGC and P&T methods. The reproducibilities of the methods were of the same order of magnitude, in the range of 1-13%. Agreement between the analytical results obtained for spiked samples and for environmental water samples by the three different methods was very good.     

Application of ultrasound-assisted extraction to the determination of contaminants in food and soil samples

The application of ultrasound-assisted extraction (UAE) to the sample preparation of environmental and food samples has increased in the last years. This technique has been used in the development of methods for the analysis of numerous contaminants, including organic compounds (pesticides, pharmaceuticals, polycyclic aromatic hydrocarbons, polyhalogenated flame retardants, etc.) and heavy metals. The aim of this work is to review the application of this extraction procedure to the analysis of contaminants in food and soil and the comparison of its use with other well-established extraction procedures. The advantages and disadvantages of this technique together with the possibility of coupling UAE with other analytical techniques will be also discussed.     

Hydrothermal liquefaction of cypress: Effects of reaction conditions on 5-lump distribution and composition

Effects of reaction temperature, reaction time and water amount on the hydrothermal liquefaction of cypress, were studied in this paper. The reaction system was divided into gas lump, water-soluble oil lump, heavy oil lump, volatile organic compounds lump, and solid residue lump. Results showed that temperature was the critical parameter for 5-lump distribution in the cypress hydrothermal conversion process. The higher temperature and longer reaction time were not usually suitable for the production of bio-oil (water-soluble oil and heavy oil). The increase in the yields of gas and volatile organic compounds was also observed as temperature was increased. However, the yield of the volatile organic compounds increased first, and then decreased with the reaction time and the water amount. High amount of water led to high conversion and bio-oil yield. The FT-IR analysis of the solid residues showed that the major peaks of cypress diminished after 280 °C. The GC–MS analysis showed that the volatile organic compounds, water-soluble oil and heavy oil comprised a mixture of organic compounds of 5–7, 5–10 and 7–26 carbons, respectively, which mainly included furfural, phenol, acids, furans and their derivatives. The WSO had similar elemental compositions but the HO had a higher content of carbon and a lower concentration of oxygen as compared to cypress.     

地质环境样品中挥发酚分析现状与进展

挥发酚被列为环境优先控制的有机污染物,已成为评价环境污染的重要指标之一。该文简述了挥发酚的化学性质及地质环境来源,概括了国内外挥发酚测定的相关标准方法,从样品预处理技术和检测技术两方面综述了近年来地质环境样品中挥发酚分析的研究现状。重点对溶剂萃取、蒸馏、固相萃取、固相微萃取和吹扫捕集等样品预处理技术,以及4-氨基安替比林分光光度法、紫外和荧光分光光度法、溴化容量法、气相色谱法、液相色谱法和酚生物传感器法等技术在地质环境样品中挥发酚分析上的应用进行了较为全面的总结,并对其未来的发展趋势进行了展望,为进一步研究挥发酚的分析技术及其环境应用提供参考。     

Rapid Simultaneous Determination of Volatile Organic Compounds in Mattress Fabric by Headspace–Gas Chromatography–Mass Spectrometry

An analytical method for simultaneously determining 32 volatile organic compounds in mattress fabrics based on static headspace coupled to gas chromatography and mass spectrometry detection was established. Samples were cut into 5?×?5?mm small pieces and placed in a 20?mL headspace vial at 90° for 30?min. To achieve the optimum conditions for the analysis, several parameters including the heating temperature, heating time, sample weight, and injection time were investigated. The results demonstrated that the most important parameter influencing the sensitivity of the analysis was the heating temperature. The optimum method showed good linearities with correlation coefficients ranged from 0.9944 to 0.9998. The limits of detection and quantification for the target compounds were in the ranges of 0.004–0.032 and 0.013–0.099?µg/?g, respectively. The method was successfully applied to determine the volatile organic compounds in six categories of mattress fabrics. The results showed that some volatile organic compounds were found, such as naphthalene, hexadecane, and 1,4-diisopropylbenzene. Moreover, the concentrations of 32 volatile organic compounds decreased following the order of jute, terylene, polyester, velboa, nylon, and cotton samples in the study. These results indicated that the method is fast, accurate, and successful for determining volatile organic compounds in mattress fabrics.     

海湾河口表层沉积物中重金属形态连续萃取方法的优化研究

采用单一萃取程序对建立的重金属形态连续萃取方法的萃取条件进行优化.分别以Ca和Mg、Fe、有机质(OM)和酸可挥发性硫(AVS)作为萃取剂释放酸溶态、还原态、有机质结合态和硫化物结合态等重金属目标形态的表征参量,考察萃取剂对相应目标形态的萃取能力和选择性.分别根据表征参量和重金属在萃取溶液中的含量变化确定最优萃取时间和萃取样液比.结果表明,优化萃取条件后,萃取剂对目标形态重金属均有很强的释放能力.酸溶态萃取剂对其它非残留态影响很小;还原态萃取剂除对酸溶态有少量提取外,对其它形态影响较小;有机质结合态萃取剂对硫化物结合态有少量萃取,对其它形态影响较小.硫化物结合态在酸溶态、还原态和有机质结合态之后萃取,避免了对这三种形态的影响.优化后的连续萃取方法对重金属形态有较好的选择性,可对海湾和河口表层沉积物中重金属的目标形态进行较为合理地分离和评价.     

Evaluation of Coriolis Micro Air Sampling to Detect Volatile and Semi-Volatile Organic Compounds

There are several analytical procedures available for the monitoring of volatile organic compounds (VOCs) in the air, which differ mainly on sampling procedures. The Coriolis micro air sampler is a tool normally designed for biological air sampling. In this paper, the Coriolis micro bio collector is used to evaluate its ability to sample organic contaminants sampling and detecting them when combined GC-MS. We also compare the use of the Coriolis micro with a standardized sampling method, which is the use of a lung box with a Nalophan^® bag. The results show that the Coriolis micro sampling method is suitable for the sampling of organic contaminants. Indeed, the Coriolis micro allows to sample and detect mainly semi-volatile molecules, while the lung box/Nalophan^® bags allow to sample more volatile molecules (highly volatile and volatile). These results were confirmed in the controlled air lab with a slight difference with the field. The simultaneous use of the both techniques allow to sample and detect a larger number of molecules with specific physicochemical properties to each sampling technique. In conclusion, the Coriolis micro can sample and detect volatile organic compounds present in air. We have shown that the development of alternative sampling methods and the use of non-target analysis are essential for a more comprehensive risk assessment. Moreover, the use of the Coriolis micro allows the detection of emergent molecules around the Thau lagoon.     

Analysis of irradiated food

Foods, e.g. chicken, shrimps, frog legs, spices, different dried vegetables, potatoes and fruits are legally irradiated in many countries and are probably also exported into countries, which do not permit irradiation of any food. Therefore all countries need analytical methods to determine whether food has been irradiated or not. Up to now, two physical (ESR-spectroscopy and thermoluminescence) and two chemical methods (o-tyrosine and volatile compounds) are available for routine analysis. Several results of the application of these four mentioned methods on different foods are presented and a short outlook on other methods (chemiluminescence, DNA-changes, biological assays, viscometric method and photostimulated luminescence) will be given.     

土壤中挥发性有机化合物的GC-MS测定

利用气相色谱－质谱联用技术，对某废弃化工厂原厂区及附近农田的土壤中可能存在的60种挥发性有机化合物进行了定性和定量分析；采用质量保证和质量控制步骤对分析结果进行监测，结果令人满意。     

Inter-laboratory trials for analysis of perfluorooctanesulfonate and perfluorooctanoate in water samples: Performance and recommendations

The ISO 25101 (International Organization for Standardization, Geneva) describes a new international standard method for the determination of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) in unfiltered samples of drinking and surface waters. The method is based on the extraction of target analytes by solid phase extraction, solvent elution, and determination by high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). For the determination of the performance of this method, more than 20 laboratories from 9 different countries participated in an inter-laboratory trial in 2006. In addition, inter-laboratory trials were conducted in 2008 and 2009 for the analysis of perfluoroalkylsubstances (PFASs), including PFOS and PFOA, in water samples by following the protocols of Japanese Industrial Standard (JIS). Overall, the repeatability coefficients of variation (i.e., within-laboratory precision) for PFOS and PFOA in all water samples were between 3 and 11%, showing a adequate precision of the ISO and JIS methods. The reproducibility coefficients of variation (i.e., between-laboratory precision) were found to vary within a range of 7–31% for surface water and 20–40% for wastewater. The recoveries of PFOS and PFOA, as a measure of accuracy, varied from 84 to 100% for surface water and from 84 to 100% for wastewater among the samples with acceptable criteria for internal standards recovery. The determined concentrations of PFASs in samples compared well with the “true” values. The results of the inter-laboratory trial confirmed that the analytical methods are robust and reliable and can be used as a standard method for the analysis of target compounds in water samples.