• Universitat de València

• Helena Prima García

In-tube solid phase microextraction (IT-SPME) is a sample preparation technique specially designed for coupling with standard analytical instrumentation such as capillary liquid chromatography. With this technique, the extraction, desorption and subsequent injection of analytes can be performed automatically, allowing a decrease in analysis times and an improvement in accuracy. However, IT-SPME systems have some disadvantages such as low extraction efficiencies (10%-30%) due to large autoelution volumes and small amounts of adsorbent phase.

Researchers at the Universitat de València have designed a new IT-SPME system, based on the principles of microfluidics, which improves the extraction efficiency of conventional IT-SPME systems. By using magnetic hybrid materials as adsorbent phase in the capillary columns, and the application of external magnetic fields, the new Magnetic-IT-SPME system allows quantitative extraction efficiencies.

The device uses a hybrid material of Fe3O4 nanoparticles supported on SiO2, immobilised on the inner surface of a fused silica capillary column, as the magnetic adsorbent phase. This column is inserted into an electromagnet connected to a current source that applies a variable magnetic field. The application of controlled magnetic field results in quantitative extraction efficiencies of the target analytes.

The new device has been successfully validated with emerging contaminants such as acetylsalicylic acid, atenolol, acetaminophen, diclofenac and ibuprofen as analytes.

This analytical instrument is applicable in all sectors where high sensitivity is required in the determination of different analytes, particularly of organic chemical species. For example:

• Environmental industry
• Pharmaceutical industry
• Food industry
• Biochemistry
• Medicinal chemistry
• Industrial chemistry

The device has the following advantages over existing equipment:

• It allows efficiency in quantitative extraction, solving one of the main drawbacks of IT-SPME systems.
• It broadens the applicability of IT-SPME systems, making it possible to take advantage of the benefits of these systems (analysis automation, precision) in specific analyses that require high sensitivity in the determination of analytes.

• Patent granted