Liquid Microjunction Surface Sampling Probe Fluid Dynamics: Computational and Experimental Analysis of Coaxial Intercapillary Positioning Effects on Sample Manipulation

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Journal of the American Society for Mass Spectrometry

DOI:https://doi.org/10.1007/s13361-011-0145-5· OSTI ID:1024256

ElNaggar, Mariam S ^[1]; Barbier, Charlotte N ^[1]; Van Berkel, Gary J ^[1]

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1. ORNL

A coaxial geometry liquid microjunction surface sampling probe (LMJ-SSP) enables direct extraction of analytes from surfaces for subsequent analysis by techniques like mass spectrometry. Solution dynamics at the probe-to-sample surface interface in the LMJ-SSP has been suspected to influence sampling efficiency and dispersion but has not been rigorously investigated. The effect on flow dynamics and analyte transport to the mass spectrometer caused by coaxial retraction of the inner and outer capillaries from each other and the surface during sampling with a LMJ-SSP was investigated using computational fluid dynamics and experimentation. A transparent LMJ-SSP was constructed to provide the means for visual observation of the dynamics of the surface sampling process. Visual observation, computational fluid dynamics (CFD) analysis, and experimental results revealed that inner capillary axial retraction from the flush position relative to the outer capillary transitioned the probe from a continuous sampling and injection mode through an intermediate regime to sample plug formationmode caused by eddy currents at the sampling end of the probe. The potential for analytical implementation of these newly discovered probe operational modes is discussed.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1024256
• Journal Information: Journal of the American Society for Mass Spectrometry, Journal Name: Journal of the American Society for Mass Spectrometry Journal Issue: 7 Vol. 22; ISSN 1044-0305
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CAPILLARIES
COMPUTERIZED SIMULATION
EDDY CURRENTS
EFFICIENCY
Electrospray ionization
FLUID MECHANICS
Fluid dynamics
GEOMETRY
IMPLEMENTATION
MASS SPECTROMETERS
MASS SPECTROSCOPY
Mass spectrometry
POSITIONING
PROBES
SAMPLING
Surface sampling
Surface sampling probe
TRANSPORT