Solvent bar microextraction of emerging pollutants from drain water samples

By -

The efficiency of a given microextraction technique depends on both thermodynamic and kinetic aspects. The distribution constant defines the maximum extractable analyte whereas the kinetic establishes the rate at which this distribution takes place. Among the kinetic factors, the efficient diffusion of the target analytes from the bulk sample solution to the acceptor phase is a key aspect. This diffusion can be easily enhanced by an efficient stirring of the sample or the acceptor phase during the extraction.

Solvent bar microextraction (SBME), which was firstly presented by Jiang and Lee in 2004, (1) enhances the diffusion of the analytes through an efficient stirring of the acceptor phase. SBME uses a solvent immobilized in the lumen and pores of a polypropylene hollow fiber as extracting phase. Both ends of the hollow fiber are sealed and the resulting solvent bar is introduced in the sample where it moves free and randomly. After the extraction, the solvent bar is recovered and the extractant is finally analyzed by an appropriate instrumental technique.

Guo and Lee, in a recent article published in Journal of Chromatography A, have proposed a SBME procedure for the extraction of six residual pharmaceuticals (naproxen, ibuprofen, ketoprofen, propanolol, diclofenac and alprenolol) from drain water, being the analytes finally determined by gas chromatography/mass spectrometry (GC/MS).(2) Taking into account the polarity of the analytes, which is a shortcoming for GC/MS analysis, a derivatization step is required. Derivatization and extraction are performed at the same time by adding the derivatizing reagent to the extraction solvent. The SBME procedure provides better results than classic hollow-fiber liquid phase microextraction using the same extraction solvent, due to the enhanced contact with the sample. Moreover, SBME provides comparable results to those obtained by solid phase microextraction, although the SBME is faster (20 vs 60 min) and it avoids carry-over as a new solvent bar is used in each new extraction.

In the referenced article (2), the readers will find the optimization of the extraction procedure, the analytical characterization of the proposed method and a critical comparison with its main counterparts.

References

(1)Solvent Bar Microextraction. Link to the article
(2)One step solvent bar microextraction and derivatization followed by gas chromatography–mass spectrometry for the determination of pharmaceutically active compounds in drain water samples. Link to the article

Comments

Post a Comment

Popular posts from this blog

Gold coated magnetic beads for electrochemical detection

By -
Image
This post summarizes an interesting article, recently accepted for publication in Analytical Chemistry, which presents an innovative use of magnetic beads. Researchers from the Osaka Prefecture University at Japan have proposed the synthesis of magnetic microbeads covered with a smooth gold layer that are used for the electrochemical detection of streptavidin (1). The synthesis, which is deeply described in the manuscript, consists of three well defined steps. First of all, the magnetic beads are introduced in a colloidal gold dispersion containing Au-nanoparticles (Au-NPs). Thanks to the opposite zeta potential of both materials (microbeads are negatively charged while Au-NPs present a positive charge), their assembly takes place by electrostatic interactions. However, the Au-NPs are not connected to each other and therefore the electrical resistance of the microbeads is too high. In a second step, the modified microbeads are dispersed in an aqueous medium containing HAuCl 4 as
Read more

Fabric phase sorptive extraction: a new generation green sample preparation strategy

By -
Image
by Dr. Abuzar Kabir, International Forensic Research Institute, Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA Fabric phase sorptive extraction (FPSE), the most recent member of the sorptive microextraction family, has innovatively incorporated both solid phase microextraction (SPME) and solid phase extraction (SPE) techniques into a single technology platform. FPSE utilizes permeable natural/synthetic fabrics e.g., cotton, polyester, fiber glass supports to chemically bind sol-gel hybrid inorganic-inorganic sorbents. A 5 cm2unit of coated fabric (2.5 cm x 2.0 cm) is typically used as the extraction media which can be inserted directly into the sample container. Extraction of the analytes is generally expedited by using a magnetic stir bar to diffuse the analyts into the sample matrix so that rapid mass transfer from the sample matrix to the extraction medium takes place.Once the mass transfer equilibrium between the FPSE media and
Read more

Highlighted articles (November 27th, 2015)

By -
Image
We recommend the following articles that deal with different aspects related with sample preparation. 1. Application of graphitic sorbent for on-line microextraction of drugs in human plasma samples . Graphitic carbon has a great potential as sorbent since it may develop different interaction chemistries with target compounds. Commercial graphitic carbons like graphitized carbon black or porous graphitic carbon presents some disadvantages including a lack of mechanical stability or a high retention (almost irreversible) of some analytes. These shortcomings are faced in this article where a new carbon material is presented. The new material is based on the deposition of a graphitic carbon layer over an inert substrate like alumina. This combination increases the mechanical strength which is key for chromatographic uses. The material has been packed in a lab made microextraction in packed sorbent (MEPS) device and it has been applied for the extraction of ropivacaine and lidocaine f
Read more