Coupling of headspace solid phase microextraction with ultrasonic extraction for the determination of chlorinated pesticides in bird livers using gas chromatography

Application of Focused Ultrasound-Assisted Extraction for the Quantification of Persistent Organic Pollutions in Liver Tissue of Giant Toad (Rhinella marina)

A simple and rapid focused ultrasound extraction method was developed for the determination of Persistent Organic Pollutants (POPs) in liver tissue obtained of giant toad (Rhinella marina) using a gas chromatography coupled to a mass detector with electron impact ionization. The performed method for POPs, was validated in fortified matrix, showing linearity from the LOQ up to 100 ng/mL; LODs and LOQs for each compound were between 1.7 and 4.8 and 3.5-7.5 ng/mL, respectively. Recovery rates were among 79%-116% for POPs determined. Finally, the method was applied in liver samples of giant toads found in a malarial area in Mexico. The sensitivity of the proposed method was good enough to ensure reliable determination of target analytes at concentration levels commonly found in this kind of samples.

Zeolitic imidazole framework templated synthesis of nanoporous carbon as a novel fiber coating for solid-phase microextraction

A novel ZIF templated nanoporous carbon was prepared as the SPME fiber coating for the extraction of organochlorine pesticides from vegetable samples.

Determination of the active constituents in Arnebia euchroma (Royle) Johnst. by ionic liquid-based ultrasonic-assisted extraction high-performance liquid chromatography

Shikonin and β,β'-dimethylacrylshikonin in Arnebia euchroma (Royle) Johnst. were extracted by ionic liquid-based ultrasonic-assisted extraction (IL-based UAE) and determined by high-performance liquid chromatography (HPLC). The dried powder of A. euchroma (Royle) Johnst. was mixed with a room temperature ionic liquid [C(6)MIM][BF(4)] to form a suspension, and then the ultrasonic extraction was performed in a water bath at ambient temperature. The calibration curve showed good linear relationship (r>0.9998) in the concentration range of 1.75-140 μg/mL for shikonin and 2.15-1360 μg/mL for β,β'-dimethylacrylshikonin. The recoveries were between 69.79% and 82.35%. The IL-based UAE is free of volatile organic solvents, and consumes less sample, time and solvent, compared with regular ultrasonic and Soxhlet extraction. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.

Hydrophobic ionic liquid-based ultrasound-assisted extraction of magnolol and honokiol from cortex Magnoliae officinalis

The hydrophobic ionic liquid of [BMIM][PF(6)] was successfully used for the ultrasound-assisted extraction of hydrophobic magnolol and honokiol from cortex Magnoliae officinalis. To obtain the best extraction efficiencies, some ultrasonic parameters including the concentration of [BMIM][PF(6)], pH, ultrasonic power and ultrasonic time were evaluated. The results obtained indicated that the [BMIM][PF(6)]-based ultrasound-assisted extraction efficiencies of magnolol and honokiol were greater than those of the [BMIM][BF(4)]-based ultrasound-assisted extraction (from 48.6 to 45.9%) and the traditional ethanol reflux extraction (from 16.2 to 13.3%). Furthermore, the proposed extraction method is validated by the recovery, correlation coefficient (R(2)) and reproducibility (RSD, n=5), which were 90.8-102.6, 0.9992-0.9998, and 1.6-5.4%, respectively.

Ionic liquid-based ultrasonic-assisted extraction of piperine from white pepper

An ionic liquid-based ultrasonic-assisted extraction (ILUAE) method has been developed for the effective extraction of piperine from white pepper powder. A series of 1-alkyl-3-methylimidazolium ionic liquids differing in composition of alkyl chain and anion were evaluated for extraction efficiency. The results indicate that both the characteristics of anions and cations have remarkable effects on the extraction efficiency. In addition, the ILUAE procedure was also optimized on some ultrasonic parameters, such as ultrasonic power, extraction time and solid-liquid ratio. Compared with the conventional heat-reflux extraction (HRE) and regular UAE, the optimized approach gained the highest extraction efficiency (from 1.950% to 3.577%) within the shortest extraction time (from 2 h to 30 min). Furthermore, the developed method was validated by the recovery, correlation coefficient (R(2)), and reproducibility (relative standard deviation (RSD), n=3). Average recoveries of piperine were between 93.5% and 98.7% at spiking levels 0.05, 0.1 and 0.2 mg mL(-1) with RSD lower than 5%. The developed method is linear at concentrations within the tested interval, with R(2) at 0.9994.

Recent developments in headspace microextraction techniques for the analysis of environmental contaminants in different matrices

Headspace microextraction procedures such as solid-phase microextraction (SPME) and single drop microextraction (SDME) or liquid-phase microextraction (LPME) are increasingly used for the extraction of environmental organic pollutants from a variety of aqueous, viscous, semisolid and solid environmental and biological matrices. In this article, recent analytical applications of these methodologies when used as an isolation and trace enrichment step prior to the analysis of organic pollutants (pesticides, polycyclic aromatic hydrocarbons, polychlorinated compounds, organotin compounds, phenolic derivatives, aromatic amines, phthalates, etc.) by gas and liquid chromatography are reviewed. The applicability and inherent limitations of headspace microextraction are also discussed. The future direction of research in this field and general trends toward commercial applications are considered.

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.