Analytical Characterization of the Electrospray Ion Source in the Nanoflow Regime

Journal Article · Mon Sep 01 04:00:00 EDT 2008 · Analytical Chemistry, 80(17):6573-6579

DOI:https://doi.org/10.1021/ac800683s· OSTI ID:939342

Marginean, Ioan; Kelly, Ryan T.; Prior, David C.; Lamarche, Brian L.; Tang, Keqi; Smith, Richard D.

We provide a thorough characterization of the low-flow electrospray as an ionization source for mass spectrometry (MS) using solutions typical for reversed-phase liquid chromatography. As expected, the electrospray operating regime strongly affects the MS signal; however, contrary to conventional wisdom, the pulsating regime consistently offers better performance than the cone-jet regime in these experimental conditions. We explain this observation by a highly efficient ionization achieved by the pulsating electrospray at low flow rates, rendering the increased charge generated by a cone-jet electrospray detrimental for transmission from atmospheric pressure to vacuum through a heated capillary interface. Over a wide range of voltages, the pulsating electrospray provides a relatively constant MS signal intensity, which depends significantly on the distance between the emitter and the MS inlet. For cone-jet electrosprays the MS signal decreases slightly with increasing voltage, but the signal is less affected by the emitter-inlet distance. At flow rates up to 100 nL/min the MS signal increases with increasing flow rate due to the larger number of ions supplied into the gas phase. At flow rates greater than 100 nL/min, the signal reaches a plateau due to increasingly unsatisfactory ionization efficiency at larger flow rates.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 939342
• Report Number(s): PNNL-SA-59989; 20496; 400412000
• Journal Information: Analytical Chemistry, 80(17):6573-6579, Journal Name: Analytical Chemistry, 80(17):6573-6579 Journal Issue: 17 Vol. 80
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory