Fast screening of terpenes in cosmetics by fluorescence quenching of the bovine serum albumin-fluorescein system confined in a single drop

By -

The presence of fragrances in cosmetics could be a problem of health concern, since some of the employed chemicals may induce asthma, migraines headaches and other adverse effects. In fact, the European Union has established a list of 26 potential allergens used as fragrances, 23 of them being volatiles terpenes. These substances may act also at low concentrations and therefore their analytical monitoring is desirable, even in theoretically fragrance-free products. Researchers from the University of Vigo (Spain) have recently presented in a research article, published in Analytica Chimica Acta, a rapid screening method for terpenes in cosmetics. This approach is based on the potential fluorescence quenching that these hydrophobic compounds induce in the bovine serum albumin (BSA)- fluorescein (F) system.

The potential quenching effect of terpenes in BSA-fluorescent indicator systems is well reported in the literature. However, this general approach does not allow the determination of terpenes at low concentrations. This shortcoming has been overcome confining the BSA-F system in an aqueous drop which is exposed to the headspace of the sample (see Figure 1), after a simple preparation process. The headspace single drop microextraction step provides a preconcentration of the targets improving the sensitivity of the determination, providing a limit of quantification as low as 0.57 µg/g.

Single drop microextraction using bovine serum albumine-fluorescein sytem as probe

This screening method provides a general index of terpenes in the cosmetic sample thanks to the similar quenching effect observed for the tested analytes. It is simple (it only requires a dissolution of the sample in a ethanolic mixture) and rapid (it spends only 10 min) and it can be used in routine analysis with excellent precision.

For further details, readers are referred to the original article. They will find there the complete procedure, the optimization process as well as the analytical characterization of the final approach.

Link to the article: Fast screening of terpenes in fragrance-free cosmetics by fluorescence quenching on a fluorescein–bovine serum albumin probe confined in a drop

Comments

Post a Comment

Popular posts from this blog

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

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

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