Multiresidue determination of organophosphorus and organochlorine pesticides in human biological fluids by capillary gas chromatography

Two multiresidue analytical methods for the simultaneous determination of organophosphorus and organochlorine pesticides in human urine and serum samples are described. The first approach is based on liquid-liquid microextraction with dichloromethane, and the second uses solid-phase extraction with C18. In both methods, the extracts are analyzed by capillary gas chromatography using nitrogen-phosphorus detection (NPD) and electron-capture detection (ECD). Limits of detection of the overall procedure of analysis are at the low ng mL(-1) level. Stability experiments have been performed with spiked urine and serum samples stored at 4 degrees C for 1 month. Finally, the solid-phase extraction procedure was applied to real-world samples. Quantification was performed by NPD or ECD, and peak identity was confirmed by use of mass-selective detection (MSD).     

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.     

环境样品中双酚类化合物的固相萃取研究进展

双酚类化合物作为一类内分泌干扰物广泛存在于环境介质中,经过多种途径迁移至人体后,可对人体产生内分泌毒性、细胞毒性、基因毒性、生殖毒性、二噁英毒性和神经毒性,已被加拿大政府风险评估识别为进一步优先控制名录。随着环境领域对双酚类化合物的广泛关注,相关研究工作逐渐向水、沉积物、灰尘和生物样品等多介质开拓。但是,由于不同环境样品在基质复杂性和污染物浓度水平等方面存在显著差异,开发提取效率高、净化选择性好、普适性强、操作简单、高通量的提取和净化方法,有助于实现环境介质中双酚类化合物的高灵敏、批量检测。近年来,新型前处理技术发展迅速,尤其是固相萃取技术,在双酚类化合物提取与净化方面取得了长足的发展,不仅在一定程度上克服了传统提取净化方法存在的耗时、耗力和耗溶剂等不足,而且为新型污染物分析提供了更多的技术支持。该文简述了典型双酚类化合物的理化性质、用途用量和环境危害,重点围绕新型固相萃取吸附剂开发和固相萃取模式转变两个方面,总结了固相萃取在双酚类化合物提取净化方法方面取得的进展。商品化固相萃取产品普适性强,在环境监测领域应用范围较广,适用于双酚类化合物的产品种类有限;新型吸附剂研发聚焦吸附容量(如介孔硅材料、碳纳米材料、金属-有机框架材料、环糊精)和选择性(如分子印迹聚合物和混合模式离子交换聚合物)两个方面,种类多样化可满足不同检测需求;越来越多的高灵敏分析仪器不断推向市场,为适应新的发展形势,固相萃取模式正逐渐向微型化、自动化、简易化等方向发展,如QuEChERS、固相微萃取、磁固相萃取等。     

Multiresidue determination of organophosphorus and organochlorine pesticides in human biological fluids by capillary gas chromatography

Two multiresidue analytical methods for the simultaneous determination of organophosphorus and organochlorine pesticides in human urine and serum samples are described. The first approach is based on liquid–liquid microextraction with dichloromethane, and the second uses solid-phase extraction with C₁₈. In both methods, the extracts are analyzed by capillary gas chromatography using nitrogen-phosphorus detection (NPD) and electron-capture detection (ECD). Limits of detection of the overall procedure of analysis are at the low ng mL^–1 level. Stability experiments have been performed with spiked urine and serum samples stored at 4?°C for 1 month. Finally, the solid-phase extraction procedure was applied to real-world samples. Quantification was performed by NPD or ECD, and peak identity was confirmed by use of mass-selective detection (MSD).     

Methods for determination of polybrominated diphenyl ethers in environmental samples - review

Polybrominated diphenyl ethers (PBDEs) are a group of persistent organic pollutants. They are used as flame retardants in plastics, paints, varnishes and textile materials. PBDEs pose great risk to the environment because of their high persistence and ability to get into the environment easily due to the lack of chemical bonds with the matrix of materials, to which they are added. Global research studies confirmed the occurrence of those compounds in the majority of elements of water and land environment. Analysis of PBDEs in environmental samples is one of the specific analytical methods of criteria that comprise low detection limits and high selectivity. The analysis of PBDEs in environmental samples is one of the specific analytical methods, in which the main criteria are low detection limits and high selectivity. In this article, a literature review of methods for environmental sample preparation and analysis of the PBDE content was presented. The article discusses the potential of modern extraction techniques such as: solid-phase microextraction, single-drop microextraction, dispersive liquid-liquid microextraction, microwave-assisted extraction, cloud point extraction, hollow fibre-liquid phase microextraction and others for the separation of PBDEs from environmental samples with a complex matrix. Among the methods for qualitative and quantitative determination of PBDEs, a particular focus was put on gas chromatography/mass spectrometry with various injection techniques and different types of sample ionisation.     

Troubleshooting in the trace analysis of organochlorine pesticides in water samples

Summary As a consequence of the high toxicity of organochlorine pesticides their presence in water for human consumption is limited by legislation. To determine these compounds at trace levels, an extraction procedure and a highly sensitive analytical technique is necessary. In this work we have used laminar disks for the solid-phase extraction of 21 organochlorine pesticides from water. The analytical technique selected is gas chromatography with electron-capture detection. A solid-phase extraction procedure is proposed, and some problems has been encountered. Low recovery of some pesticides has been obtained, because of their adsorption by the walls of containers. To prevent this adsorption, addition of 20% methanol before the sampling step is proposed. Adsorption of pesticides by the organic matter present in water samples was also observed. Pesticides can be adsorbed by the membrane filters usually used to remove suspended particulate matter from water samples. Different kinds of filters have been tested, and the occurrence of the problem has been confirmed. The use of laminar disks in this work has overcome this problem.     

食品及环境样品中双酚类物质的前处理及检测方法研究进展

双酚类物质作为一种环境内分泌干扰物,广泛存在于食品包装材料及环境介质中,对生态环境造成污染,也对人体健康产生一定危害。双酚残留是目前重要的食品安全问题,检测食品和环境样品中的双酚类物质的含量对人体健康具有重要的意义。由于残留目标物浓度通常较低,且实际样品存在基质干扰,因此需经一定的样品前处理,并结合仪器分析方法,提高检测效率,增强分析灵敏度与可靠性。常用的前处理分析方法主要有液液萃取、微波辅助萃取、固相萃取、固相微萃取、基质分散固相萃取、QuEChERS等,常用仪器分析方法包括液相色谱法、气相色谱法、毛细管电泳法、酶联免疫吸附测定法、生物传感器法等。该文综述了食品及环境样品中双酚类物质的样品前处理及仪器分析方法,为双酚类化合物的残留监测提供了参考依据。     

Sample preparation for planar chromatography

High-performance thin-layer chromatography has favorable properties for high-throughput separations with a high matrix tolerance. Sample preparation, however, is sometimes required to control specific matrix interferences and to enhance the detectability of target compounds. Trends in contemporary applications have shifted from absorbance and fluorescence detection to methods employing bioassays and mass spectrometry. Traditional methods (shake-flask, heat at reflux, Soxhlet, and hydrodistillation) are being challenged by automated instrumental approaches (ultrasound-assisted and microwave-assisted solvent extraction, pressurized liquid extraction, and supercritical fluid extraction) and the quick, easy cheap, efficient, rugged, and safe extraction method for faster and streamlined sample processing. Liquid-liquid extraction remains the most widely used approach for sample clean-up with increasing competition from solid-phase extraction. On-layer sample, clean-up by planar solid-phase extraction is increasingly used for complex samples and in combination with heart-cut multimodal systems. The automated spray-on sample applicator, the elution head interface, biological detection of target and non-target compounds, and straightforward mass spectrometric detection are highlighted as the main factors directing current interest toward faster and simpler sample workflows, analysis of more complex samples, and the determination of minor contaminants requiring high concentration factors.     

Microwave-assisted micellar extraction coupled with solid-phase extraction for preconcentration of pharmaceuticals in molluscs prior to determination by HPLC

A simple and specific analytical method was developed and tested for the determination of pharmaceuticals in mollusc samples. A combination of microwave-assisted micellar extraction (MAME) and solid-phase extraction (SPE) using a non-ionic surfactant, polyoxyethylene 10 lauryl ether, was examined to extract and determine simultaneously a group of pharmaceuticals such as carbamazepine, clorfibric acid, ketoprofen, naproxen, bezafibrate and ibuprofen by liquid chromatography using UV-diode array detector. The MAME extraction performance was evaluated by studying various parameters such as the volume and concentration of surfactant and microwave conditions. Finally, an OASIS HLB cartridge was used as an optimum SPE sorbent to clean up the extracts and preconcentrate the selected analytes. The proposed method showed satisfactory linearity and reproducibility (between 3 and 15%), as well as detection limits ranging from 30 to 220 ng/g. Finally, the method was successfully applied to the determination of the target pharmaceuticals in various kinds of mollusc samples. This study has demonstrated that microwave-assisted micellar extraction with solid-phase extraction may be used as a viable alternative to conventional methods for the extraction of pharmaceuticals in this type of matrices.     

Recent applications of atomic spectroscopy coupled with magnetic solid-phase extraction techniques for heavy metal determination in environmental samples: A review

Atomic spectroscopy is the most popular approach to determine the presence of heavy metals in the environment. Heavy metals are potentially toxic and have various negative effects on many living organisms, including humans. With the rapid increase in the variety of industries and human activities, large amounts of heavy metals are released into the atmosphere, water, and soil. Heavy metal analysis of environmental samples is very important for determining the exposure limits. Environmental samples are highly complex matrices, and various sample preparation techniques have been developed for the extraction of heavy metals from them, including magnetic solid-phase extraction (MSPE). The use of MSPE in heavy metal analysis has recently gained significant attention owing to a number of advantages. MSPE technique overcomes main issues such as phase separation, handling, and column packing. The use of magnetic adsorbents in sample preparation has grown over the past few years, making MSPE a promising technique for sample preparation. The objective of this review article is to provide the latest applications of MSPE coupled with atomic spectroscopy for heavy metal determination in environmental samples. In addition, new magnetic adsorbents and their analytical merits are emphasized.     

Online in situ analysis of selected semi-volatile organic compounds in water by automated microscale solid-phase extraction with large-volume injection/gas chromatography/mass spectrometry

A fully automated analytical method was developed for the online in situ analysis of selected semi-volatile organic compounds in water. The method used a large-volume injection/gas chromatography/mass spectrometry coupled with a fully automated microscale solid-phase extraction technique, which was based on x-y-z robotic techniques. Water samples were extracted by using a 96-well solid-phase extraction plate. For most analytes included in this study, the obtained linear calibrations ranged from 0.05 to 5.0 microg/L with correlation coefficients of 0.996-1.000, the method detection limits were less than 0.1 microg/L, and the relative recoveries were in the range of 70-120% with a relative standard deviation of less than 15% for fortified reagent water samples. The applications to chlorinated tap water, well water, and river water have been validated. The obtained results were similar to those resulting from fortified reagent water samples for all analytes except metribuzin, bromacil, aldrin, and methoxychlor. Matrix effects were observed for these analytes. In general, this fully automated analytical method was rugged, reliable, and easy to operate, and was capable of providing real-time data to water treatment and distribution systems as well as water reservation and protection systems. In addition, the method could reduce the analytical costs associated with sample collection, transportation, storage, and preparation.     

Stir bar sorptive extraction of parabens, triclosan and methyl triclosan from soil, sediment and sludge with in situ derivatization and determination by gas chromatography-mass spectrometry

The aim of this research work was the evaluation of stir-bar sorptive extraction (SBSE) in combination with an in situ derivatization to determine parabens (methylparaben, isopropylparaben, n-propylparaben, butylparaben and benzylparaben), triclosan and methyltriclosan in soil samples. This is the first time that this approach has been applied to the determination of these compounds in soil samples, providing important advantages over conventional extraction techniques, such as minimization of sampling handling, complete elimination of the use of organic solvents and simplification of the analytical procedure with reduced time consumption. The enriched target analytes were desorbed thermally using a thermodesorption system coupled to a gas chromatograph and a mass spectrometer. The optimized derivatization and SBSE extraction conditions, as well as the analytical characteristics of the method were obtained using spiked soil samples. The proposed methodology proved to be easy to use and sensitive, with limits of detection between 80 ng/kg and 1.06 μg/kg, and reproducibility values below 13%. The accuracy of the method was evaluated at two concentration levels, obtaining apparent recoveries between 91% and 110%. The matrix composition significantly influenced the extraction procedure, and a need to adopt a standard additions protocol is apparent. The analytes assayed were determined successfully in different environmental soil samples.     

Miniaturized sample preparation and separation methods for environmental and drug analyses.

Miniaturized extraction and separation media have been successfully developed from precisely controlled technologies. In this article, recent developments in these high performance analytical methods, such as miniaturized sample preparation methods and the coupling of these techniques with microscale separation systems, have been reviewed, along with some applications to environmental and biological analysis. The advantage of the miniaturization is not only for the environmental compatibility but also for the developments of the high performance analytical systems. Down-sizing also makes it possible to investigate and introduce various compounds and materials as novel media (such as tailor-made materials and devices) in separation science. As a typical example of the novel miniaturized sample preparation system, the applications of fibrous materials for microcolumn liquid-phase separation methods are described.     

Multiresidue Analysis of Phenylurea Herbicides in Environmental and Drinking Water by Capillary Electrophoresis

The present paper describes the application of capillary electrophoresis in the micellar mode to the separation and quantitative determination of five phenylurea herbicides, viz. monuron, linuron, diuron, isoproturon, and monolinuron, in water samples. Using uncoated fused silica capillary and phosphate-borate buffer (pH 7.0) containing SDS, the five pesticides are resolved in less than 15 min and quantitatively determined by an ultraviolet detector at 244 nm. Method optimization and validation parameters are presented. Good linearity and repeatability were observed for all the compounds studied (correlation coefficients 0.999). The feasibility of the method developed was tested by simultaneous determination of these herbicides in environmental and drinking water samples at the minimum residue levels (MRLs) (0.1 μg/L) after solid-phase extraction (SPE) preconcentration procedure.     

Gas Chromatographic–Mass Spectrometric Analysis of Hydrocarbons and Other Neutral Organic Compounds in Volcanic Gases Using SPME for Sample Preparation

Knowledge of the chemical composition of volcanic exhalation is important in providing information on volcanic feeding systems and on the characteristics of the gaseous compounds emitted into the atmosphere. This paper reports a novel analytical method that makes use of capillary gas chromatography coupled to mass spectrometry, preceded by solid-phase micro extraction for sample enrichment. Such an approach enables considerable expansion of the number of neutral organic compounds that can be positively identified in volcanic exhalation. Data obtained from analysis of real samples are also reported.     

冷冻干燥技术在环境水样有机新污染物前处理中的应用进展

有机新污染物是一类在先进分析技术帮助下新鉴定的、现有法规未管制的、人为源的有机污染物.有机新污染物主要包括药品与个人护理、农药、全氟化合物、内分泌干扰物等,其会产生内分泌干扰效应、诱发抗性基因传播,还对人类和野生生物的生存与发展构成潜在威胁,因此检测环境样品中的有机新污染物浓度对生态环境和人体健康具有重大意义.由于环境...     

Implementation of solid-phase microextraction with micellar desorption method for priority phenolic compound determination in natural waters

Eleven phenolic compounds considered by the Environmental Protection Agency to be priority pollutants are extracted and determined in different water samples. The method involves the extraction and clean-up step of target compounds by solid-phase microextraction and micellar desorption (SPME-MD) and a second step of determination by liquid chromatography with diode array detection. Different fibers and surfactants are evaluated for the analysis of these target analytes in water samples. In the optimum conditions for the SPME process, recoveries for the target compounds are between 80% and 109%; relative standard deviations are lower than 10%, and detection limits are in the range 0.3-3.5 ng/mL. The main advantages of this method are the combination of time and efficiency, safety, and an environmentally friendly process for sample extraction prior to instrumental determination. This demonstrates that SPME-MD can be used as an alternative to traditional methods for the extraction and determination of priority phenolic compounds in natural waters from different origins.     

Environmental analysis based on luminescence in organized supramolecular systems

The use of organized supramolecular systems—including micellar media and cyclodextrin inclusion complexes—combined with luminescence techniques in the study and determination of compounds and elements of environmental interest from 1990 to 2005 is reviewed. Analyses of environmental samples performed using fluorescence, photochemically induced fluorescence and phosphorescence spectroscopy as well as liquid chromatography, capillary electrophoresis and flow injection with luminescence detection in the presence of these organized media are described in detail.     

Before the injection--modern methods of sample preparation for separation techniques

The importance of sample preparation methods as the first stage in an analytical procedure is emphasised and examined. Examples are given of the extraction and concentration of analytes from solid, liquid and gas phase matrices, including solvent phase extractions, such as supercritical fluids and superheated water extraction, solid-phase extraction and solid-phase microextraction, headspace analysis and vapour trapping. The potential role of selective extraction methods, including molecular imprinted phases and affinity columns, are considered. For problem samples alternative approaches, such as derivatisation are discussed, and potential new approaches minimising sample preparation are noted.