A review on magnetic field-assisted solid-phase microextraction techniques

The use of electromagnetic waves to improve the efficiency of analytical separation methods has received high attention in recent years. This is done in two ways, one involving the use of a magnetic absorbents and the other one using an external magnetic field to enhance the extraction efficiency. In this review, the application of magnetic field for enhancing the selectivity and sensitivity of analytical sample preparation methods, by focusing on solid-phase microextraction (SPME), is surveyed and evaluated. Additionally, the efficiency and reliability of different magnetic sorbent-enhanced SPME and magnetic field-enhanced SPME methods are discussed. It was revealed that applying an external magnetic field in the SPME techniques improves the analytical figure of merits, particularly in complex matrices like human body fluids. It was demonstrated that the use of the external magnetic field in SPME can increase fiber’s lifespan. Additionally, the enhancing effect of the external electromagnetic field, due to the paramagnetic attraction and diamagnetic repulsion, is discussed.