Octadecyl pipette tip coupled to electrospray ionization mass spectrometry

By -
The availability of easy to handle interfaces for the direct analysis of samples by mass spectrometry is highly desirable as it clearly simplifies the analytical measurement process. Moreover, the reduction of errors in the final result given can be highlighted as a great advantage. These interfaces must reduce the amount of interferents that can eventually reach the detector while providing a reproducible and quantitative response.

Researchers from the University of Hong Kong developed a pipette-tip-ESI-MS technique for the direct analysis of solid samples. The interface coupled a pipette-tip with a syringe and a syringe pump (1). Now they have evolved this interface to the microextraction context by replacing the empty pipette tip by a new one filled with conventional reverse-phase C18 sorbent (2). In this way, after retention, the analytes are directly sprayed out for the ESI-MS analysis by applying a high voltage to the syringe needle (see the diagram in this picture free available in the Journal webpage). The so-called pipette-tip based microextraction has been favorably evaluated for the analysis of protein solutions containing salts and detergents as well as the quantitation of ketamine and norketamine in urine.

Those of you who are familiar with the analysis of proteins solutions are aware about the incompatibility of such matrices with the direct infusion MS analysis. The present approach has been favorably evaluated for such bioanalytical process, so you will find the reading of this contribution in the microextraction context attractive.

Our readers more interested in the quantitative information will also find this information useful to simplify the sample treatment.

From Microextraction Tech, we are sure that all our followers will enjoy with the reading of this contribution.

References
(1) Direct analysis of herbal powders by pipette-tip electrospray ionization mass spectrometry. Link to the article

(2) Rapid analysis of raw solution samples by C18 pipette-tip electrospray ionization mass spectrometry. 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

Rotating Disk Sorptive Extraction

By -
Image
by Prof. Dr. Pablo Richter, Department of Inorganic and Analytical Chemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile. The modern trends in analytical chemistry promote efficiency and green technology in sample preparation. In this context, our research team developed a new technique in 2009 that is capable of extracting pollutants from liquid samples on a rotating PTFE disk with one surface coated with an extraction phase [1]. The disk has embedded a miniature magnetic rod, which allows rotation. We have termed this procedure rotating-disk sorptive extraction (RDSE). RDSE is currently available in two configurations. In the classic version (Figure 1), the extraction phase is a polymeric film adhered to one side of the PTFE disk (configuration 1). In this configuration, polydimethylsiloxane (PDMS), nylon and octadecyl (C18) have been used as the sorptive material for the extraction of low-polarity analytes (Log Kow between 3 and 7) [1-12]. However...
Read more