In-tube solid-phase microextraction capillary column packed with mesoporous TiO₂ nanoparticles for phosphopeptide...

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Phosphopeptide enrichment is crucial for understanding cellular signaling pathways.
• Traditional methods often lack the selectivity and sensitivity required for complex biological matrices.

Purpose of the Study:

• To develop a novel in-tube solid-phase microextraction (SPME) column for selective phosphopeptide enrichment.
• To couple this SPME column with Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS) for sensitive detection.

Main Methods:

• Mesoporous titanium dioxide (TiO2) nanoparticles were synthesized using sol-gel and solvothermal methods.
• The TiO2 nanoparticles were packed into a capillary column using a slurry packing technique with in situ polymerized monolithic frits.
• The developed TiO2-packed column was evaluated for phosphopeptide enrichment using various protein standards and applied to nonfat milk samples.

Main Results:

• The TiO2-packed column demonstrated high specific surface area and excellent selectivity for phosphopeptides, outperforming traditional solid-phase extraction (SPE).
• The system achieved high sensitivity, detecting as low as 10 fmol of a β-casein enzymatic hydrolysis sample.
• Selective enrichment of phosphopeptides was successfully demonstrated in a complex biosample (nonfat milk).

Conclusions:

• The in-tube SPME column packed with mesoporous TiO2 nanoparticles offers a highly selective and sensitive platform for phosphopeptide analysis.
• This method is suitable for the detection of phosphorylated peptides in practical biological samples, advancing phosphoproteomics research.