Recent developments in the analysis of brominated flame retardants and brominated natural compounds

This article reviews recent literature on the analysis of brominated flame retardants (BFRs) and brominated natural compounds (BNCs). The main literature sources are reviews from the last five years and research articles reporting new analytical developments published between 2003 and 2006. Sample pretreatment, extraction, clean-up and fractionation, injection techniques, chromatographic separation, detection methods, quality control and method validation are discussed. Only few new techniques, such as solid-phase microextraction (SPME) or pressurized liquid extraction (PLE), have been investigated for their ability of combining the extraction and clean-up steps. With respect to the separation of BFRs, the most important developments were the use of comprehensive two-dimensional gas chromatography for polybrominated diphenyl ethers (PBDEs) and the growing tendency for liquid-chromatographic techniques for hexabromocyclododecane (HBCD) stereoisomers and of tetrabromobisphenol-A (TBBP-A). At the detection stage, mass spectrometry (MS) has been developed as well-established and reliable technology in the identification and quantification of BFRs. A growing attention has been paid to quality assurance. Interlaboratory exercises directed towards BFRs have grown in popularity and have enabled laboratories to validate analytical methods and to guarantee the quality of their results. The analytical procedures used for the identification and characterization of several classes of BNCs, such as methoxylated polybrominated diphenyl ethers (MeO-PBDEs) (also metabolites of PBDEs), halogenated methyl or dimethyl bipyrroles (DBPs), are reviewed here for the first time. These compounds were generally identified during the routine analysis of BFRs and have received little attention until recently. For each topic, an overview is presented of its current status.     

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.     

Determination of sulfur components in natural gas: A review

More stringent environmental regulations as well as higher demands presently being imposed on the sulfur content of natural gas feed-stocks for chemical processes necessitate the development of new analytical procedures for sulfur determination in natural gas. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by environmental regulation institutions and modern chemical industry. The complexity of the natural gas matrix as well as the extremely low concentration levels at which the sulfur species occur make the development of these analytical methods a true challenge. In this review the three steps common for analytical methods for trace analysis in complex matrices, i.e. pretreatment, chromatographic separation, and detection, are discussed in detail. Possible methods for calibration of the system are discussed in the final section. Various techniques to determine sulfur in natural gas are described. Depending on the application, the most suitable system has to be selected. For example, for on-line application in a hazardous area a simple and rugged system is required, i.e. a simple gas chromatograph with a flame photometric detector, while for laboratory application a more complex instrument including preconcentration, column switching, and more exotic detection systems could be more suitable. Therefore it is crucial to define the requirements of the instrument at an early stage and use the information in this review article to develop/select a dedicated instrument/procedure for the problem at hand.     

Novel contribution of chromatography in the development and analyses of metformin hydrochloride in biological and environmental samples

Globally, metformin hydrochloride (HCl) is the most commonly used antidiabetic drug and provides safe medication because of low risk of the side effects (lactic acidosis). Therefore, various researches have been established in pharmacodynamics and pharmacokinetic studies using various analytical applications such as calorimetry, spectrophotometry, and chromatography. But the chromatographic techniques are most widely used methods for the analysis of metformin HCl. This review discussed the different chromatographic methods used for the analysis of metformin HCl and its sample preparation for the isolation in different biological and environmental samples. Moreover, the mechanism for the fragmentation of ion products in LC–MS/MS is indicated for high throughput of the methods involved in the determination of metformin HCl in various sample matrices. The advancement in the chromatographic modalities provides the wide range of assays discussed herein.     

Separation and preconcentration procedures for the determination of lead using spectrometric techniques: a review

Lead is recognized worldwide as a poisonous metal. Thus, the determination of this element is often required in environmental, biological, food and geological samples. However, these analyses are difficult because such samples contain relatively low concentrations of lead, which fall below the detection limit of conventional analytical techniques such as flame atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry. Several preconcentration procedures to determine lead have therefore been devised, involving separation techniques such as liquid-liquid extraction, solid phase extraction, coprecipitation and cloud point extraction. Citing 160 references, this paper offers a critical review of preconcentration procedures for determining lead using spectroanalytical techniques.     

Challenges in the determination of aminoglycoside antibiotics,a review

Residues of antibiotics (ABs) in the aquatic environment and in food of animal origin represent a major concern, as prolonged exposure to ABs is a serious health hazard, related to both the side effects of prolonged use and the risk of developing bacterial resistance to various ABs. Given the low levels of the AB residues in complex matrices, the development of sensitive analytical methods represents a major challenge. This is certainly true for the aminoglycoside ABs (AGs) which lack a chromophore and show poor chromatographic properties in reversed-phase liquid chromatography. This paper reviews the current state of the art in the determination of AGs. Attention is paid to extraction, sample clean-up, chromatographic separation, and detection of AGs in both environmental and food samples and in plasma and serum. A general workflow for the analysis of AGs is presented which takes into account the matrix and required level of information.     

Simultaneous detection of total and halogenated hydrocarbons in complex environmental samples

A state-of-the-art gas chromatographic system for automatic simultaneous detection of halogenated and normal hydrocarbons has been developed, which consists of a standard Hewlett-Packard 5880 with a fused silica capillary column, whose effluent is split between the standard flame ionization detector and a Tracor Hall electroconductivity detector. The system provedes excellent capillary chromatography results and high sensitivity for halogenated compounds (a detection limit of 1 ppm Archlor 1254 in fuel oil). Reliability has been provides in the daily analysis of complex environmental samples. Emergency response cleanup and the containment of hazardous chemical spills and chemical dump sites forces one to deal with samples that are very complex. The contain large numbers of naturally occurring organic compounds and varying types of organic pollutants. Capillary chromatographic techniques of gas chromatographic and gas chromatographic/mass spectrometric analyses are necessary to achieve the resolution required for the analysis of these samples.     

The role of alternative specimens in toxicological analysis

The use of alternative specimens in the field of toxicology was first described in 1979, when hair analysis was used to document chronic drug exposure. Since then, the use of these 'alternative' samples has gained tremendous importance in forensic toxicology, as well as in clinic toxicology, doping control and workplace drug testing. It is not surprising, therefore, that a large number of papers dealing with the determination of several classes of drugs in saliva, sweat, meconium and hair have been published ever since, owing to the fact that chromatographic equipment is becoming more and more sensitive, mass spectrometry (and tandem mass spectrometry) being the most widely used analytical tool, combined with gas or liquid chromatography. 'Alternative' specimens present a number of advantages over the 'traditional' samples normally used in toxicology (e.g. blood, urine and tissues), namely the fact that their collection is not invasive, their adulteration is difficult, and they may allow increased windows of detection for certain drugs. The main disadvantage of this kind of samples is that drugs are present in very low concentrations, and therefore high-sensitivity techniques are required to accomplish the analysis. This paper reviews a series of publications on the use of alternative specimens, with special focus on the main analytical and chromatographic problems that these samples present, as well on their advantages and disadvantages over traditional samples in documenting drug exposure.     

Research progress of rapid detection of typical environmental pollutants based on chromatographic technologiesEI北大核心CSCD

对复杂环境介质中的典型污染物进行快速、精准甚至远程连续自动的检测,是控制环境污染、确保环境和生态安全的重要前提。近年来,基于色谱技术的典型环境污染物快速检测方法发展迅猛,主要包括样品快速制备和目标物快速检测两方面。辅助萃取、快速液相萃取、QuEChERS等样品前处理方法具有萃取效率高、溶剂消耗少、操作简便快速等优点。快速检测技术可在几秒到半小时内提供检测结果,主要包括实验室和现场检测。本文综述了2019年以来基于色谱技术的典型环境污染物快速检测研究新进展。介绍了萃取技术和基于试验设计的样品快速制备,实验室快速检测、便携仪器现场检测及遥感技术远程检测,提出了色谱技术快速检测环境污染物的挑战和展望。     

Determination of pesticide transformation products: A review of extraction and detection methods

Pesticides are widely applied and they can produce a variety of transformation products (TPs), through different pathways and mechanisms. Nowadays there is a growing interest related to the determination of pesticide TPs in several matrices (environmental, food and biological samples), due to these compounds can be more toxic and persistent than parent compounds, and some of them can be used as markers of exposure to different pesticides. Although solid-phase extraction (SPE) is mainly used for the extraction of TPs, alternative techniques such as solid-phase microextraction (SPME) and liquid-phase extraction (LPE) can be used. These TPs are mainly determined by liquid chromatography (LC) due to the recent developments in this technique, especially when it is coupled to mass spectrometry (MS) detectors, allowing the determination of known and/or unknown TPs. Furthermore, MS is a very valuable tool for the structural elucidation of unknown TPs. This review discusses all phases of analytical procedure, including sample treatment and analysis, indicating the main problems related to the extraction of TPs from several matrices due to their high polarity, as well as the different alternatives found for the simultaneous determination of parent compounds and TPs, using chromatographic techniques coupled to MS detection.     

High Performance Liquid Chromatography (HPLC) with Fluorescence Detection for Quantification of Steroids in Clinical,Pharmaceutical, and Environmental Samples: A Review

Steroids are compounds widely available in nature and synthesized for therapeutic and medical purposes. Although several analytical techniques are available for the quantification of steroids, their analysis is challenging due to their low levels and complex matrices of the samples. The efficiency and quick separation of the HPLC combined with the sensitivity, selectivity, simplicity, and cost-efficiency of fluorescence, make HPLC coupled to fluorescence detection (HPLC-FLD) an ideal tool for routine measurement and detection of steroids. In this review, we covered HPLC-FLD methods reported in the literature for the steroids quantification in clinical, pharmaceutical, and environmental applications, focusing on the various approaches of fluorescent derivatization. The aspects related to analytical methodology including sample preparation, derivatization reagents, and chromatographic conditions will be discussed.     

A review of the determination of persistent organic pollutants for environmental forensics investigations

The field of environmental forensics emerged in the 1980s as a consequence of legislative frameworks enacted to enable parties, either states or individuals, to seek compensation with regard to contamination or injury due to damage to the environment. This legal environment requires stringent record keeping and defendable data therefore analysis can sometimes be confined to data to be obtained from certified laboratories using a standard accredited analytical method. Many of these methods were developed to target specific compounds for risk assessment purposes and not for environmental forensics applications such as source identification or age dating which often require larger data sets. The determination of persistent organic pollutants (POPs) for environmental forensic applications requires methods that are selective but also cover a wide range of target analytes which can be identified and quantified without bias. POPs are used in a wide variety of applications such as flame retardants, fire suppressants, heat transfer agents, surfactants and pesticides mainly because of their chemical inertness and stability. They also include compounds such as dioxins that can be unintentionally produced from industrial activities. POPs are persistent in the environment, bioaccumulative and/or toxic and therefore require analytical methods that are sensitive enough to meet the low detection limits needed for the protection of the environment and human health. A variety of techniques, procedures and instruments can be used which are well suited for different scenarios. Optimised methods are important to ensure that analytes are quantitatively extracted, matrix coextractables and interferences are removed and instruments are used most effectively and efficiently. This can require deviation from standard methods which can open the data up to further scrutiny in the courtroom. However, when argued effectively and strict QA/QC procedures are followed the development and optimization of methods based on investigation specific scenarios has the potential to generate better quality and more useful data.     

Monitoring and characterization of polyaromatic compounds in the environment

This paper provides an overview of analytical techniques and instruments used to monitor and characterize polycyclic aromatic compounds (PACs) in the environment. The basic operating principles of various analytical approaches and systems are presented. The review deals specifically with spectroscopic methods, chromatographic and hyphenated techniques, and field monitoring devices. Emphasis is given to portable devices that can be used under field conditions. Specific examples of analytical techniques and instruments developed in the authors's laboratories will be discussed to illustrate the usefulness and potential of these approaches for environmental monitoring and characterization of PACs.     

Determination of nitrated-polyaromatic hydrocarbons (nitro-PAHs) in environmental samples by high resolution chromatographic techniques

An analytical procedure is described for the fractionation of organic compounds present in environmental samples and the determination of nitro polyaromatic hydrocarbons (nitro-PAHs). Both low and high resolution liquid chromatography are employed for the prefractionation of the soluble organic fraction (SOF) extracted from particulate matter or gaseous pollutants collected on adsorption traps. High resolution gas chromatography is used to analyze four fractions containing alkanes, PAHs, nitro-PAHs, and other polar PAHs. Nitrogen-containing species are separated by GC and detected specifically using an alkali flame (NPD) detector. Flame ionization (FID) detection, GC-MS of positive ions, and negative ion chemical ionization MS of the whole fraction is used for the identification and quantitation of the various components. The composition of SOF extracted from particulate matter emitted from diesel exhausts is elucidated and a large number of nitro-PAHs identified by the combination of the various techniques.     

环境水质中酚类优先监测物的气相色谱法测定

以气相色谱法（ＧＣ）测定了环境水质中的重点酚类污染物。选择乙酸酐作衍生化试剂、甲苯为萃取剂,比较了不同的衍生ｐＨ条件,给出了氢火焰离子化检测器（ＦＩＤ）分离测定酚类污染物的精密度和检出限。方法简便实用,经５家实验室验证表明：适用于监测地表水和污水中的酚类物质。６种酚类优先监测物的检测限为０．６～７μｇ／Ｌ。     

Strategy of glycerolipid separation and quantitation by complementary analytical techniques. Plenary lecture

Although improved systems for chromatographic resolution continue to be developed there is good reason to believe that no single method will be capable fo complete separation of all lipid mixtures including the geometric, positional and stereochemical isomers in each molecular species. Furthermore, the chromatographic systems giving the highest resolution usually yield the least complete recoveries of components and require separate procedures of quantitation. It is therefore necessary to develop appropriate strategies that yield the required resolution as a result of consecutive application of complementary analytical techniques. At the present time, the original combination of thin-layer and gas--liquid chromatography has been joined by the combination of thin-layer and liquid, and liquid and gas--liquid chromatography with both liquid and gas--liquid chromatography being frequently coupled to mass spectrometry with computerized data processing. Internal standardization with hydrogen flame ionization provides a simple quantitative detection for gas chromatography, while mass spectrometry serves a similar purpose in liquid chromatography, although a much more extensive calibration may be required for quantitation. Special advantages for both separation and quantitation of most neutral lipid mixtures are derived from enzymic and chemical modification of the samples prior to chromatography. With imaginative work-up of samples, superior qualitative and quantitative results can frequently be obtained by appropriate combination of chromatographic techniques of limited resolving power.     

Analytical procedures for the determination of emerging organic contaminants in plant material: A review

In this review, recent developments for the determination of emerging organic contaminants (EOCs) in plant tissues are discussed focusing on the homogenization, extraction and determination steps involved. Eleven classes of EOCs, namely antibiotics, analgesics, antiepileptics, antidepressants, antiseptics, plasticizers, fragrances, surfactants, flame retardants, and phenoxy acid herbicides, have been evaluated. Methods are critically reviewed in terms of all the analytical steps involved in the analysis, sampling and sample preparation, separation, and the detection strategies employed. The extraction from tissue samples was performed in most cases by solid–liquid extraction, whereas the clean-up was performed by solid-phase extraction. The identification and quantification of EOCs in crops from the agricultural field (i.e. parts per billion range) is usually performed by using mass spectrometry techniques such as single quadrupole mass spectrometry or tandem mass spectrometry coupled to high resolution chromatographic techniques. Enzyme-linked immunosorbent assays are more rarely used. New developments such as in vivo solid-phase microextraction (SPME) and the assessment of the bioavailability–bioaccesibility of contaminants in crops are shown. The main scope of this review is to critically evaluate the current state of the art of the analytical techniques used and to identify the research needs in the determination of EOCs in crops.     

Determination of phosphine and other fumigants in air samples by thermal desorption and 2D heart-cutting gas chromatography with synchronous SIM/Scan mass spectrometry and flame photometric detection

Fumigants and volatile industrial chemicals are particularly hazardous to health when a freight container is fumigated or the contaminated material is introduced into its enclosed environment. Phosphine is now increasingly used as a fumigant, after bromomethane--the former fumigant of choice--has been banned by the Montreal Protocol. We have enhanced our previously established thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method by integrating a second gas chromatographic dimension and a flame photometric detector to allow the simultaneous detection of phosphine and volatile organic compounds (VOCs), providing a novel application. A thermal desorption system is coupled to a two dimensional gas chromatograph using both mass spectrometric and flame photometric detection (TD-2D-GC-MS/FPD). Additionally, the collection of mass spectrometric SIM and Scan data has been synchronised, so only a single analysis is now sufficient for qualitative scanning of the whole sample and for sensitive quantification. Though detection limits for the herewith described method are slightly higher than in the previous method, they are in the low μL m(-3) range, which is not only below the respective occupational exposure and intervention limits but also allows the detection of residual contamination after ventilation. The method was developed for the separation and identification of 44 volatile substances. For 12 of these compounds (bromomethane, iodomethane, dichloromethane, 1,2-dichlorethane, benzene, tetrachloromethane, 1,2-dichloropropane, toluene, trichloronitromethane, ethyl benzene, phosphine, carbon disulfide) the method was validated as we chose the target compounds due to their relevance in freight container handling.     

Congener-specific determination of dioxins and related compounds by gas chromatography coupled to LRMS,HRMS, MS/MS and TOFMS

Their characteristics as persistent organic pollutant and their toxicity (2,3,7,8-TCDD is named as a known human carcinogen) make the dioxins and related compounds a focus of interest in environmental analytical chemistry. In view of the widespread distribution of dioxins in the environment, these compounds must be monitored in several matrices, such as air, effluents, soil, sludge and biological samples. The analytical methodologies are especially difficult owing to the complexity of the mixtures of congeners (210 PCDD/Fs and 209 PCBs) and to the low detection limits required (ppb to ppq). Moreover, time-consuming sample preparation steps are needed owing to the presence of a large number of interfering compounds. The different toxicity of each congener requires the development of congener specific methods. This review of trace dioxin determination by mass spectrometry (MS) includes sample preparation and chromatographic separation. In this Special Feature, the use of different MS techniques such as low-resolution MS (LRMS) and high-resolution MS (HRMS) is discussed in terms of selectivity and sensitivity. The performances of other MS techniques, such as tandem MS (MS/MS) and time-of-flight MS (ToFMS), are compared. Quantification techniques, especially the isotopic dilution method, are also discussed. Conclusions and future perspectives are outlined.