Electrospray Regime Controls Sensitivity and Quantitative Performance in Micro- and Nano-Flow CE–ESI–MS

embryonic samples at single-cell-scale input, CJ significantly increased the number of detected metabolite features and improved recovery of functionally annotated protein groups. These results establish ESI regime as a controllable driver of sensitivity and quantitative performance in CE-ESI-MS and provide practical guidance for selecting ionization conditions for trace-limited analyses.