Department of Chemistry, East Carolina University, Greenville, North Carolina 27858, USA.
J Am Soc Mass Spectrom. 2009 Dec;20(12):2199-205. doi: 10.1016/j.jasms.2009.08.007. Epub 2009 Aug 27.
Electrospray ionization (ESI) mass spectrometry (MS) has proven to be an extremely powerful technique for studying the stoichiometry and binding strength of peptide-metal complexes. We have found a significant new problem in the ESI-MS of zinc-peptide systems involving the deposition of zinc in the ESI emitter. This deposition of zinc during the experiment removes a significant amount of zinc ions from the solution, impacting the resulting mass spectral intensities used to quantify the amount of the zinc-bound species. Analysis of infused zinc-peptide samples with atomic absorption spectrometry and with a custom-built nanoflow ESI source confirms the alteration of the analyte solutions with positive or negative or no potential applied to the emitter. Ultimately, the location of the zinc deposition was determined to be the stainless steel emitter. The use of a custom-built nanoESI interface using glass emitters was found to mitigate the zinc deposition problem. The phenomenon of metal deposition warrants further investigation as it may not be limited to just zinc and may represent a significant obstacle in the ESI-MS analysis of all protein-metal systems.
电喷雾电离（ESI）质谱（MS）已被证明是研究肽-金属配合物的化学计量和结合强度的极其强大的技术。我们在涉及锌-肽系统的 ESI-MS 中发现了一个重要的新问题，即在 ESI 发射器中沉积锌。实验过程中锌的沉积会从溶液中去除大量的锌离子，从而影响用于定量结合锌的物种量的质谱强度。使用原子吸收光谱法和定制的纳流 ESI 源对注入的锌-肽样品进行分析，证实了在施加正或负或无电势的情况下，分析物溶液会发生变化。最终，确定锌沉积的位置是不锈钢发射器。使用定制的纳米 ESI 接口使用玻璃发射器被发现可以减轻锌沉积问题。金属沉积现象值得进一步研究，因为它可能不仅限于锌，并且可能代表所有蛋白质-金属系统的 ESI-MS 分析中的一个重大障碍。
