Fractionation of chlorinated and brominated persistent organic pollutants in several food samples by pyrenyl-silica liquid chromatography prior to GC–MS determination

Evaluation of the Methods to Predict Total Serum Lipids and to Determine 22 POPs in the Serum of Pregnant Women

The objectives of this study were to determine the suitability of total serum lipid (TSL) concentrations, which were calculated by three different formulae, for pregnant women and to optimize the improved matrix solid-phase dispersion (MSPD) method. The results showed that the TSL predicted by the three formulae were significantly correlated to our measured values (sums of the total cholesterol, triglycerides and phospholipids contents). In particular, one of formulae was the most statistically suitable for pregnant women. Meanwhile, an improved MSPD method was developed to extract 22 POPs. The developed MSPD method was compared with SPE and EPA (8081 & 8082) to evaluate the performance of each extract method. The method validation showed that the results obtained using the improved MSPD method were closest to the actual concentration (adjusted by lipids), and the dispersion of the data was minimal.

Focused ultrasound solid-liquid extraction and gas chromatography tandem mass spectrometry determination of brominated flame retardants in indoor dust

This study presents a focused ultrasound solid-liquid extraction (FUSLE) and gas chromatography tandem mass spectrometry method for the determination of brominated diphenyl ethers (BDEs), from mono- to hexa-congeners, in indoor dust. This approach provided a simple, fast, and economical method. After the solvent extraction selection, the FUSLE conditions were studied using a central composite design. Finally, the number of extraction cycles was studied. The selected conditions were 8 mL of 3:1 n-hexane-acetone mixture as extraction solvent, at a power of 65% for 20 s. The proposed method allowed accurate determination of BDEs, with recovery values around 100% and detection limits between 0.05 and 0.8 ng g(-1). It also has advantages over other existing methods in terms of simplicity, analysis time, and solvent consumption. The analysis of several indoor dust samples showed high concentration values of BDEs 47, 99, 100, 153, and 154 in some of the samples, moreover, BDEs 47 and 99 were found in all samples.

Development of an Analytical Protocol for the Determination of Polybrominated Biphenyls in Water by Enzyme-Linked Immunosorbent Assay

A novel immunoassay has been developed for the quantitative determination of polybrominated biphenyls (PBBs) using indirect competitive format. A new method was developed to synthesize PBBs congener (PCB15) hapten and its artificial immunogen, then the polyclonal antibodies. The assay was optimized concerning the coating conjugate and antibody concentration, incubation time and temperature, the tolerance to organic solvents and so on. Under optimized conditions, PBB15 can be determined in the concentration range of 0.01-100 μg L-1 with a detection limit of 0.02 μg L-1. The cross-reactivities of the assays were below 8%. While water samples could be analyzed directly.

Analysis of PBDEs in soil, dust, spiked lake water, and human serum samples by hollow fiber-liquid phase microextraction combined with GC-ICP-MS

A novel method for the analysis of four polybrominated diphenyl ethers (PBDEs) in environmental and human serum samples based on hollow fiber-liquid phase microextraction (HF-LPME) followed by gas chromatography-inductively coupled plasma mass spectrometric (GC-ICP-MS) detection has been developed. The organic solvent in the porous hollow fiber was first dipped into the sample for extraction at a given time, and the retracted organic phase was introduced into the GC-ICP-MS for analysis. The addition of methanol has a strong effect on the HF-LPME extraction efficiency. Other significant parameters affecting the extraction efficiency of HF-LPME were also studied. HF-LPME was effective to isolate the analytes from the complex matrix. Under the optimized conditions, the detection limits of the proposed method varied from 15.2 to 40.5 ng/L. In general, the relative standard deviations (RSDs) were less than 10%. Good linearity was obtained with the correlation coefficients all better than 0.999. The proposed method is simple, quick, few microliters of organic solvent required, and is especially suitable for the analysis of the real sample with small amount available. The overall process of HF-LPME with GC-ICP-MS was applied successfully for the determination of polybrominated diphenyl ethers (PBDEs) in environmental and spiked human serum samples, and the results were satisfactory.

Feasibility of two multidimensional techniques, heart-cut MDGC and GC×GC, for the separation of PCBs and PBDEs

The feasibility of heart-cut MDGC-ECD and GCxGC-muECD for the separation of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) has been evaluated. Among the different column combinations tested, the best results were obtained when using either a DB-5 type or an HT-8 column as the first dimension combined with a mid-polar stationary phase (50% phenyl) as the second dimension. The co-elutions between the target PCBs and PBDEs in the first dimension were satisfactorily resolved once transferred to the second column. Repeatability and intermediate precision were satisfactory in both systems, considering retention times in both dimensions. Nevertheless, peak area/volume precision was better for heart-cut MDGC since software for the data analysis in the case of GCxGC was still under development. The need for multiple injections of the same extract on the heart-cut MDGC system was the main drawback since the analysis time it increased. GCxGC becomes then a valuable alternative able to achieve the same performance in one injection. However, the GCxGC data analysis is still very time-consuming and needs further development. The applicability of both separation techniques was shown using a human breast milk sample with low concentrations of PCBs (0.2-227 pg/g fresh weight) and PBDEs (1.2-41 pg/g fresh weight).

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.

Sample handling strategies for the determination of persistent trace organic contaminants from biota samples

Even after emergence of most advanced instrumental techniques for the final separation, detection, identification and determination of analytes, sample handling continues to play a basic role in environmental analysis of complex matrices. In fact, sample preparation steps are often the bottleneck for combined time and efficiency in many overall analytical procedures. Thus, it is not surprising that, in the last two decades, a lot of effort has been devoted to the development of faster, safer, and more environment friendly techniques for sample extraction and extract clean up, prior to actual instrumental analysis. This article focuses on the state of the art in sample preparation of environmental solid biological samples dedicated to persistent organic pollutants (POPs) analysis. Extraction techniques such as Soxhlet extraction, sonication-assisted extraction, supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), pressurised liquid extraction (PLE) and matrix solid-phase dispersion (MSPD) are reviewed and their most recent applications to the determination of POPs in biota samples are provided. Additionally, classical as well as promising novel extraction/clean-up techniques such as solid phase microextraction (SPME) are also summarized. Finally, emerging trends in sample preparation able to integrate analytes extraction and their adequate clean-up are presented.