Hansen Carl Frederik Marc, Dobrovolskis Lukas, Janfelt Christian
Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
J Am Soc Mass Spectrom. 2025 Mar 5;36(3):473-482. doi: 10.1021/jasms.4c00341. Epub 2024 Oct 2.
Since desorption electrospray ionization mass spectrometry (DESI-MS) was first presented in 2004, the fundamental design of the sprayer has undergone relatively minor modifications. This changed in 2022 when Takats and co-workers implemented the desorption electro-flow focusing (DEFFI) sprayer design by modifying the sprayer from a commercial DESI system, leading to significantly improved spatial resolution and robustness compared with the traditional DESI-MSI sprayer design. Here, we present the design of a new DEFFI sprayer that can be built from standard fittings and connectors in combination with an aluminum spray head that can be machined in most mechanic workshops. The new design represents a cost-efficient approach to improved DESI-MSI on mass spectrometers from all vendors, including high-resolution instruments such as Orbitraps and FT-ICR. The new DEFFI sprayer is demonstrated on a QExactive Orbitrap mass spectrometer, resulting in a massively improved ion yield compared with the classic DESI sprayer. The improved ion yield enables DESI-MSI at ion injection times down to 5 ms, allowing for DESI-MSI at a potentially very high speed. More importantly, the DEFFI sprayer delivers a more robust and focused spray, which is easier to use and requires less optimization. It provides high spatial resolution with limited effort compared with previous modifications of the traditional DESI design. Imaging of rat testis was performed at pixel sizes down to 12 μm, suggesting a spatial resolution of approximately 30 μm, which may have potential for further improvement.
自2004年首次提出解吸电喷雾电离质谱法（DESI-MS）以来，喷雾器的基本设计仅经历了相对较小的改进。2022年情况有所改变，Takats及其同事通过对商用DESI系统的喷雾器进行改造，采用了解吸电流聚焦（DEFFI）喷雾器设计，与传统的DESI-MSI喷雾器设计相比，显著提高了空间分辨率和稳定性。在此，我们展示了一种新型DEFFI喷雾器的设计，它可以由标准配件和连接器与一个铝制喷雾头组合而成，该铝制喷雾头在大多数机械加工车间都能加工。这种新设计为所有供应商的质谱仪（包括诸如轨道阱和傅里叶变换离子回旋共振等高分辨率仪器）上改进DESI-MSI提供了一种经济高效的方法。新型DEFFI喷雾器在QExactive轨道阱质谱仪上得到了验证，与经典DESI喷雾器相比，离子产率大幅提高。离子产率的提高使得在离子注入时间低至5毫秒时也能进行DESI-MSI，从而有可能实现非常高速度的DESI-MSI。更重要的是，DEFFI喷雾器产生的喷雾更稳定、更集中，更易于使用且所需优化更少。与传统DESI设计的先前改进相比，它只需付出有限的努力就能提供高空间分辨率。对大鼠睾丸进行成像时，像素尺寸低至12μm，这表明空间分辨率约为30μm，且可能还有进一步提升的潜力。
