NanoSplitter LC-MS

Performing electrospray ionization (ESI) from conventional-scale (1-4 mm) LC columns is inefficient: mixing in the splitter causes severe band-broadening, and ion-pairing in the relatively high flow electrospray can cause significant components to be undetected in the mass spectrometer   In the NanoSplitter below, the flow for MS analysis is split from the heart of the eluant stream, avoiding band-broadening due to parabolic flow or mixing due to dead volumes.  Use of a true nanospray needle avoids ion suppression, as shown in the sample spectra.  Only 0.1% of the eluant need be consumed, making NanoSplitter LC-MS a non-destructive technique. 

Figure 1.  Schematic diagram of the NanoSplitter LC-MS interface.  Eluant from LC column enters at right. Flow through splitter chamber is parabolic; however, only central volume is sampled for MS.  Restriction needle valve controls back-pressure, regulating nanospray flow rate and split ratio.  Flow through needle valve may be collected in fractions. 

Figure 2.  Comparison of NanoSplitter LC-MS with conventional LC-MS interface.  By coupling conventional-scale LC to a nanospray ESI emitter the limit of detection is improved, as evidenced by the higher S/N at right.  In addition, ion suppression (peak under yellow arrow) is greatly reduced.