Combination of extraction tip and MALDI-TOF-MS for efficient separation and analysis of cysteine-containing peptides

In our work, a new extraction tip with gold-modified polymer is developed. The simple, self-made and extremely economical tips were successfully applied to capture cysteine-containing peptides. The loading capacity of a tip (column bed: 0.3 mm diameter, 5 mm length) is 2–4 μg peptides. We can make one tip in 30 s and each costs less than 0.1 cent. The use of these tips can achieve a stable analysis with less background interference, even for 10 ng target peptides. Compared with other separation techniques, our method can save much time and energy while providing a means to selectively capture cysteine-containing peptides from complex analyte due to the strong interaction. All results showed that our new extraction tips have minimal cost and perfect selectivity; thus they have great potential in sample pretreatment systems for proteomics.