Ionization and transmission efficiency in an electrospray ionization-mass spectrometry interface

Journal Article · Sat Sep 01 04:00:00 EDT 2007 · Journal of the American Society for Mass Spectrometry, 18(9):1582-1590

DOI:https://doi.org/10.1016/j.jasms.2007.05.018· OSTI ID:914674

Page, Jason S; Kelly, Ryan T; Tang, Keqi; Smith, Richard D

The efficiency of sample ionization by electrospray ionization (ESI) and the transmission of the charged droplets and gas-phase ions through an ESI interface were investigated in order to advance the understanding of how these factors affect mass spectrometry (MS) sensitivity. In addition, the effects of the ES emitter distance to the inlet, solution flow rate, and inlet temperature to the ionization and transmission efficiency were characterized. Quantitative measurements of ES current loss throughout the ESI interface were accomplished by electrically isolating the front surface of the interface from the inner wall of the heated inlet capillary, enabling losses on the two surfaces to be distinguished. The ES current lost to the front surface of the ESI interface was also spatially profiled with a linear array of 340-µm-dia. electrodes placed adjacent to the inlet capillary entrance. Current transmitted as gas-phase ions was differentiated from charged droplets and solvent clusters by directly measuring sensitivity with a single quadrupole mass spectrometer. The study has revealed a large sampling efficiency into the inlet capillary (>90% at an emitter distance of 1 mm), a global rather than a local gas dynamic effect on the shape of the ES plume due to the gas flow conductance limit of the inlet capillary, a large (>80%) loss of analyte after transmission through the inlet due to incomplete desolvation at a solution flow rate of 1.0 µL/min, and a decrease in analyte peak intensity at lower temperatures, despite a large increase in ES current transmission efficiency. These studies provide a clearer understanding of the parameters affecting ion transmission into the mass spectrometer, and will serve to guide the design of more efficient instrument interfaces.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 914674
• Report Number(s): PNNL-SA-53862; 400412000
• Journal Information: Journal of the American Society for Mass Spectrometry, 18(9):1582-1590, Journal Name: Journal of the American Society for Mass Spectrometry, 18(9):1582-1590 Journal Issue: 9 Vol. 18; ISSN 1044-0305; ISSN JAMSEF
• Country of Publication: United States
• Language: English

Related Subjects

47 OTHER INSTRUMENTATION
DESIGN
EFFICIENCY
ELECTRODES
EQUIPMENT INTERFACES
IONIZATION
MASS SPECTROMETERS
MASS SPECTROSCOPY
MASS TRANSFER
SAMPLE PREPARATION
SENSITIVITY