Polystyrene-impregnated paper substrates for direct mass spectrometric analysis of proteins and peptides in complex matrices

摘要

Direct analysis of proteins and peptides in complex matrices is of significant importance for biological, medicinal and toxicological studies. Paper spray mass spectrometry is a promising method for the rapid determination of target compounds in various samples, but such a protocol is greatly limited by the hydrogen-bond and van der Waals interactions between the paper substrate and proteins and peptides. In this study, we reported the development of a robustly hydrophobic polystyrene-impregnated paper substrate with a surface energy of 49.0 mN m?1 for paper spray in the analyses of proteins and peptides. The substrate was prepared by first coating polystyrene microspheres on the surface of filter paper followed by baking at 180 °C. We found that the baking temperature and coating amount of polystyrene had pronounced effects on the surface properties of the generated paper and the performance of paper spray in the analysis of target compounds. In addition, the capability of polystyrene-impregnated paper during paper spray was closely related to the composition of spray solvent. The developed paper has also been used for the measurement of various proteins and peptides (e.g., cytochrome c, lysozyme, myoglobin, angiotensin II and hemoglobin) in complex matrices (e.g., PBS and Tris buffer solutions and whole blood samples). The results demonstrated that in contrast to uncoated filter paper, the analysis sensitivity of paper spray using polystyrene-impregnated paper could be improved 12–1348-fold. This could ultimately make the PS-impregnated paper a potential substrate for paper spray in the direct analysis of proteins and peptides in various complex samples.