Multiple Heart-Cutting Two-Dimensional Chip-HPLC Combined with Deep-UV Fluorescence and Mass Spectrometric Detection

In this work, we introduce a new two-dimensional chip-based high-performance liquid chromatography (2D chip-HPLC) approach, which enables multiple transfers from the first dimension effluent onto the column head of the second separation dimension. By merging injection, separation, and detection features on a fused silica chip in a dead volume-free manner, all extra-column peak dispersion effects can be reduced to an absolute minimum. The application of intrinsic fluorescence detection with excitation in the deep-UV spectral region and electrospray ionization mass spectrometry after the first and second separation dimension, respectively, enables the label-free analysis of complex samples, as exemplarily shown for a pesticide mixture and a tryptic digest.