Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Room 2210, Norman, OK, 73019, USA.
Anal Bioanal Chem. 2023 Nov;415(28):6961-6973. doi: 10.1007/s00216-023-04870-w. Epub 2023 Aug 15.
Capillary electrophoresis mass spectrometry (CE-MS) is an emerging analytical tool for microscale biological sample analysis that offers high separation resolution, low detection limit, and low sample consumption. We recently developed a novel microsampling device, "spray-capillary," for quantitative low-volume sample extraction (as low as 15 pL/s) and online CE-MS analysis. This platform can efficiently analyze picoliter samples (e.g., single cells) with minimal sample loss and no additional offline sample-handling steps. However, our original spray-capillary-based experiments required manual manipulation of the sample inlet for sample collection and separation, which is time consuming and requires proficiency in device handling. To optimize the performance of spray-capillary CE-MS analysis, we developed an automated platform for robust, high-throughput analysis of picoliter samples using a commercially available CE autosampler. Our results demonstrated high reproducibility among 50 continuous runs using the standard peptide angiotensin II (Ang II), with an RSD of 14.70% and 0.62% with respect to intensity and elution time, respectively. We also analyzed Ang II using varying injection times to evaluate the capability of the spray-capillary to perform quantitative sampling and found high linearity for peptide intensity with respect to injection time (R > 0.99). These results demonstrate the capability of the spray-capillary sampling platform for high-throughput quantitative analysis of low-volume, low-complexity samples using pressure elution (e.g., direct injection). To further evaluate and optimize the automated spray-capillary platform to analyze complex biological samples, we performed online CE-MS analysis on Escherichia coli lysate digest spiked with Ang II using varying injection times. We maintained high linearity of intensity with respect to injection time for Ang II and E. coli peptides (R > 0.97 in all cases). Furthermore, we observed good CE separation and high reproducibility between automated runs. Overall, we demonstrated that the automated spray-capillary CE-MS platform can efficiently and reproducibly sample picoliter and nanoliter biological samples for high-throughput proteomics analysis.
毛细管电泳质谱联用 (CE-MS) 是一种新兴的分析工具，用于微尺度生物样本分析，具有高分离分辨率、低检测限和低样品消耗的特点。我们最近开发了一种新型微采样装置“喷雾毛细管”，用于定量低体积样品提取（低至 15 pL/s）和在线 CE-MS 分析。该平台可以有效地分析皮升级样本（例如单细胞），具有最小的样品损失和无需额外的离线样品处理步骤。然而，我们最初的基于喷雾毛细管的实验需要手动操作样品入口进行样品收集和分离，这既耗时又需要精通设备操作。为了优化喷雾毛细管 CE-MS 分析的性能，我们开发了一种自动化平台，使用市售的 CE 自动进样器对皮升级样品进行稳健、高通量的分析。我们的结果表明，使用标准肽血管紧张素 II (Ang II) 进行 50 次连续运行时具有高度重现性，强度的 RSD 为 14.70%，洗脱时间的 RSD 为 0.62%。我们还使用不同的进样时间分析 Ang II，以评估喷雾毛细管进行定量采样的能力，发现肽强度与进样时间具有高度线性关系（R>0.99）。这些结果表明，喷雾毛细管采样平台具有使用压力洗脱（例如直接进样）对低体积、低复杂度样品进行高通量定量分析的能力。为了进一步评估和优化自动化喷雾毛细管平台对复杂生物样品的分析，我们使用不同的进样时间对 Ang II 加标大肠杆菌裂解物进行在线 CE-MS 分析。我们保持了 Ang II 和大肠杆菌肽的强度与进样时间的高度线性关系（在所有情况下 R>0.97）。此外，我们观察到自动运行之间具有良好的 CE 分离和高重现性。总体而言，我们证明了自动化喷雾毛细管 CE-MS 平台可以高效、重现地采样皮升级和纳升级生物样品，用于高通量蛋白质组学分析。
