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

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 the sample matrixis reached, the FPSE media is removed from the sampling container and dried. Subsequently, the FPSE media is exposed to a small volume of organic solvent to elute/back-extract the preconcentrated analytes. The prepared sample in a suitable organic solvent can then be injected into the analytical instrument for analysis.

Schematic representation of FPSE procedure

How does FPSE combine SPME and SPE?

FPSE, similar to SPME or other sorptive microextraction techniques, is an equilibrium extraction system. However, unlike SPME, FPSE uses high mass of sorbents (comparable to SPE). In addition, FPSE exploits its quasi flow-through extraction media that allows the sample matrix passing through it (as in SPE) and helps aquiring near-exhaustive extraction under equilibrium extraction condition in a relatively short period of time. The migration of aqueos sample matrix through the extraction media speeds up the mass transfer from the sample matrix to the extraction media, leading to high absolute recovery of analytes in a short period of time. Subsequently, a small volume of organic solvents can easily access to the interaction sites of the sorbent to break sorbent-analyte interaction and quantitatively elute/back-extract the analytes.

Advantages of FPSE over conventional sorptive extraction/microextraction techniques:

Integration of SPE and SPME in FPSE has offered numerous advantages. Some of them are listed below:

1. FPSE is a green sample preparation approach.
2. Extraction can be carried out in both equilibrium extraction (like SPME) and exhaustive extraction (like SPE) mode.
3. Can be used to prepare complex samples containing particles, debris, biomass, proteins, cells and does not require any matrix clean-up (e.g., filtration, centrifugation etc.).
4. High sorbent loading translates into high sample capaticity and wide range of linearity.
5. Permeable substrate and sponge-like porous sol-gel sorbent ensures fast exraction equilibrium.
6. Hybrid inorganic-organic sorbents demonstrate high mechanical, chemical, and solvent stability.
7. Chemical bonding between the substrate and the sorbent allows employing any organic solvent of choice for analytes elution/back-extraction after the extraction. As a result, the prepared sample can be analyzed in multiple analytical systems (GC/HPLC/CE) for complementary information.
8. Completely eliminates solvent evaporation/sample reconsitution step, a time confusing, environment polluting and error prone step often inevitable in SPE.
9. Unlike inert supports used in SPME/SPE, the fabric support used in FPSE complements the ultimate polarity of the FPSE media through hydrophobic or hydrophic property of the substrate used.
10. Due to the integration of SPE and SPME in FPSE, any sorbent used in both the techniques can be used FPSE. This opens up the possibility of utilizing hundreds of different sorbents used in both the techniques.

About the author

Dr. Abuzar Kabir is a Visiting Research Assistant Professor at the International Forensic Research Institute (IFRI), Department of Chemistry and Biochemistry, Florida International University (FIU), Miami, Florida. He has received his Ph.D. in analytical chemistry from University of South Florida (USF), Tampa, Florida, USA. The major focus of his research interest has been the synthesis and applications of novel sol-gel derived advanced material systems to solve analytical chemistry problems. His recent inventions, fabric phase sorptive extraction (FPSE) and dynamic fabric phase sorptive extraction (DFPSE) have earned tremendous attention from researchers and academics working in the field. He has developed and formulated more than thirty high efficiency sol-gel hybrid inorganic-organic sorbents based on Silica, Titania, Zirconia chemistries. Sol-gel mediated molecularly imprinted polymers (MIP) are among his diversified research interests. He is the author and co-author of more than 25 peer-reviewed journal articles. He is always open to collaborative research.  For further information on his inventions and research collaboration, Dr. Kabir can be reached at akabir@fiu.edu.