Comparison of gampi paper and nanofibers to chromatography paper used in paper spray-mass spectrometry

Two series of "papers" that were made from natural fibers and synthetic fibers, respectively, were examined for use in paper-spray mass spectrometry and the results were compared to chromatography paper that is currently being used. In the former case, four types of papers were used, including gampi paper, tengujou paper, glassine paper and cicada paper, and the findings show that the limit of detection can be improved when gampi paper was used. This is because gampi paper is very tough and extremely thin (thickness, <20 μm), which permits sample molecules to be translated and evaporated nearly instantly. Since ionization occurs within a very short period, an abundance of ions is formed, leading to a dramatic improvement in the limit of detection. Meanwhile, a series of tough, thin synthetic fibers, including a microarray membrane (hollow and fibrous) and nanofibers, were also tested. The papers were prepared from polycarbonate, polylactic acid and poly-L-lactic acid (PLLA), respectively, by means of a co-axial electrospinning technique. The findings show that the limit of detection also can be improved, when a PLLA nanofiber was used. This is because this type of paper-like nanofiber is also very thin, tough and hydrophobic, which permits to ionization to occur within a very short period. Detailed information on methods for synthesizing these fibers and their use in the analysis of a real sample are also reported.