Department of Chemistry, MC 111, University of Illinois at Chicago, Chicago, Illinois 60607, United States.
Anal Chem. 2012 Nov 6;84(21):9410-5. doi: 10.1021/ac302230e. Epub 2012 Oct 10.
The potential of laser desorption postionization mass spectrometry (LDPI-MS) imaging for small molecule quantification is demonstrated here. The N-methylpiperazine acetamide (MPA) of ampicillin was adsorbed into polyelectrolyte multilayer surface coatings composed of chitosan and alginate, both high molecular weight biopolymers. These MPA-ampicillin spiked multilayers were then shown to inhibit the growth of Enterococcus faecalis biofilms that play a role in early stage infection of implanted medical devices. Finally, LDPI-MS imaging using 7.87 eV single-photon ionization was found to detect MPA-ampicillin within the multilayers before and after biofilm growth with limits of quantification and detection of 0.6 and 0.3 nmol, respectively. The capabilities of LDPI-MS imaging for small molecule quantification are compared to those of MALDI-MS. Furthermore, these results indicate that 7.87 eV LDPI-MS imaging should be applicable to quantification of a range of small molecular species on a variety of complex organic and biological surfaces. Finally, while MS imaging for quantification was demonstrated here using LDPI, it is a generally useful strategy that can be applied to other methods.
本文展示了激光解吸/光电离质谱成像（LDPI-MS）在小分子定量方面的潜力。氨苄西林的 N-甲基哌嗪乙酰胺（MPA）被吸附到壳聚糖和海藻酸钠组成的聚电解质多层表面涂层中，这两种都是高分子量生物聚合物。然后，这些含有 MPA-氨苄西林的夹层被证明可以抑制粪肠球菌生物膜的生长，生物膜在植入医疗器械的早期感染中起作用。最后，使用 7.87 eV 单光子电离的 LDPI-MS 成像被发现可以在生物膜生长前后检测到多层中的 MPA-氨苄西林，定量和检测限分别为 0.6 和 0.3 nmol。LDPI-MS 成像在小分子定量方面的能力与 MALDI-MS 进行了比较。此外，这些结果表明，7.87 eV LDPI-MS 成像应该适用于在各种复杂的有机和生物表面上对多种小分子物质的定量。最后，虽然本文使用 LDPI 展示了用于定量的 MS 成像，但这是一种普遍有用的策略，可应用于其他方法。
