We developed a highly efficient and low‐cost organic solvents‐resistant microfluidic paper‐based analytical device (μPAD) coupled with paper spray mass spectrometry (PS‐MS) for quantitative determination of C₁₈‐ceramide as a prognostic biomarker for several diseases. Several models of μPAD patterns have been examined to select the most resistant and efficient microchannel barriers, which can provide continuous spray at ionization zone and prevent “coffee ring” effect. Moreover, the developed μPAD has enabled the analysis of low concentration of C₁₈‐ceramide because of the maximum supply of deposited analyte through microchannel. The MS results confirmed the formation of doubly and singly charged metal ion complexes between ceramide and different metal ions. Notably, the complexation that occurs between lithium ions and C₁₈‐ceramide showed a high relative abundance compared with other formed complexes. Taking into account the relative abundance of complex [Cer + Li]⁺ at 572.8 m/z, it can be considered as a stable ion and therefore be used for the analysis of C₁₈‐ceramide at low concentrations. Complexation of C₁₈‐ceramide and lithium confirmed with quantum chemical calculations. The proposed method represents good linearity with a regression coefficient of 0.9956 for the analysis of C₁₈‐ceramide and reaches a limit of detection to 0.84 nM. It has been adapted successfully for practical application in human serum samples with high recovery values in range of 92%–105%. The developed μPAD‐MS technique provides clear advantages by reducing the experimental steps and simplifying the operation process and enables to identify subnanomolar concentration of C₁₈‐ceramide in human serum samples.

中文翻译：

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用于定量分析 C18-神经酰胺生物标志物的耐溶剂微流体纸基分析装置/喷雾质谱。

我们开发了一种高效且低成本的耐有机溶剂微流体纸基分析装置 (μPAD) 与纸喷雾质谱 (PS-MS) 相结合，用于定量测定 C ₁₈神经酰胺作为多种疾病的预后生物标志物。已经检查了多种 μPAD 模式模型，以选择最具抵抗力和最有效的微通道屏障，这些屏障可以在电离区提供连续喷雾并防止“咖啡环”效应。此外，开发的 μPAD 能够分析低浓度的 C ₁₈- 神经酰胺，因为通过微通道最大程度地供应沉积的分析物。MS 结果证实了神经酰胺和不同金属离子之间形成了双电荷和单电荷金属离子络合物。值得注意的是，与其他形成的配合物相比，锂离子和 C ₁₈神经酰胺之间发生的络合显示出较高的相对丰度。考虑到复合物 [Cer + Li] ⁺在 572.8 m/z 处的相对丰度，它可以被认为是一个稳定的离子，因此可用于分析低浓度的 C _{18 -}神经酰胺。C _{18 的}络合-神经酰胺和锂通过量子化学计算证实。所提出的方法表现出良好的线性，回归系数为 0.9956，用于分析 C ₁₈神经酰胺，检测限达到 0.84 nM。它已成功应用于人血清样品的实际应用，其回收率范围为 92%–105%。开发的 μPAD-MS 技术通过减少实验步骤和简化操作过程提供了明显的优势，并且能够识别人血清样品中亚纳摩尔浓度的 C ₁₈神经酰胺。