Develop New Interfaces for Coupling LC with MS

LC/MS plays a significant role in analytical chemistry. However, high flow rate of eluents is not compatible with MS ionization. We have developed a novel splitting method^28-30 which allows real-time MS monitoring of LC-separated analytes and subsequent online analyte collection.

In this approach, a PEEK capillary tube with a micro-orifice drilled on the tube sidewall is used to connect with LC column. A small portion of LC eluent emerging from the orifice can be directly ionized by LS-DESI-MS with a negligible time delay (few ms) while the remaining analytes exiting the tube outlet can be collected following DESI-MS monitoring.

The DESI-MS analysis of eluted compounds shows narrow peaks and high sensitivity, due to the extremely small dead volume of the orifice used for LC eluent splitting (as low as 4 nL) and the freedom to choose favorable DESI spray solvent. In addition, online derivatization using reactive DESI is possible for supercharging separated proteins and for enhancing their signals without introducing extra dead volume.

Unlike UV detector used in traditional preparative LC experiments, our method is applicable to compounds without chromophores.

References

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