Magnetic nanocomposite-based SELDI probe for extraction and detection of drugs, amino acids and fatty acids.

The use of carbon black-FeO magnetic nanocomposite (CB-FeO) as a probe for surface-enhanced laser desorption ionization mass spectrometry (SELDI-MS) with a high extraction efficiency and sensitive detection is described. The magnetic nanocomposite was synthesized and fully characterized using X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, Ultraviolet-Visible spectroscopy, transmission electron microscopy and nitrogen sorption. The feasibility of the SELDI probe to extract and detect three classes of drugs (labetalol, metoprolol, doxepin, desipramine, triprolidine and methapyrilene) spiked in wine is demonstrated. All the drugs were successfully and reproducibly extracted and detected with high efficiency and with limits of detection (LOD) between 1 and 1000 pg mL. The adsorption capacity of the nanocomposite for the drugs was evaluated by UV-Vis spectroscopy. The results showed that 27.8-36.1% of the drugs were adsorbed on the magnetic probe within 3 min. The nanocomposite was also applied for efficient analysis of amino acids and fatty acids. Both types of analytes can be extracted within a few minutes and then successfully quantified by SELDI-MS. Graphical abstract A schematic presentation of carbon black-FeO magnetic probe for SELDI analysis of small molecules. The probe containing the analyte(s) is collected with the aid of a magnet and deposited on the target plate for mass spectrometry analysis.