Fast capillary electrophoresis–time-of-flight mass spectrometry using capillaries with inner diameters ranging from 75 to 5 μm

Abstract

Fast electrophoretic separations in fused silica capillaries (CE) coupled to time-of-flight mass spectrometry (TOF-MS) are presented. CE separations of the model analytes (epinephrine, norepinephrine, dopamine, histidine, and isoproterenol) under conditions of high electric field strengths of up to 1.25 kV cm(-1) are completed in 20 s. Coupling of CE with TOF-MS is accomplished using a coaxial sheath liquid electrospray ionization interface. The influence of parameters inherent to the interface and their effects, including suction pressure and dilution, are discussed. In addition to standard capillaries of 75 and 50 μm inner diameter (ID), separations in capillaries with IDs of 25, 15, and 5 μm have been successfully applied to this setup. The analytical performance is compared over this range of capillary dimensions, and both advantages and disadvantages are discussed.

Small-Volume Analysis of Cell–Cell Signaling Molecules in the Brain

“…Chiral analysis of excitatory acids from the brain by CE has been reported (Wang et al, 2011;Wagner et al, 2012). In addition, CE has a potential for high-throughput analysis, and separation times as fast as 20 s have been reported for catecholamines, as well as a fourfold increase in sensitivity by using short separation capillaries with small inner diameters (Grundmann and Matysik, 2011). A sampling approach that further enhances the concentration sensitivity of CE separations is single-drop microextraction; analyte enrichment ranging from B7000-fold for chiral amino acids and up to B30 000-fold for fluorescent dyes has been reported (Alothman et al, 2012).…”

“…MS confirmation of analytes detected using LIF is important; however, transferring a particular separation method from a CE-LIF instrument to one with MS detection is challenging because of LIF buffer incompatibilities with MS detection. Recent CE-MS work has shown that separations using smaller inner diameter capillaries (eg, 5 mm) were shown to be less affected by buffer composition (Grundmann and Matysik, 2011).…”

Microbeam-coupled capillary electrophoresis

“…where L is the length of the capillary, V is the applied voltage and m is the electrophoretic mobility (3) ; hence, faster separations may be achieved more readily by using short capillaries (4) than by using higher voltages.…”

“…From Figure 3, detection times for Rh-123 and GSSG-NDA are 9 and 16 min, respectively, leading to a maximum throughput of 3-5 cells h 21 . These flow times can be significantly accelerated, without loss of separation (4) , by reducing the capillary length. For example, a reduction in the capillary length from 1 m to 30 cm, without changing the separation voltage, will result in a ninefold decrease in migration time.…”

Portable, Battery Operated Capillary Electrophoresis with Optical Isomer Resolution Integrated with Ionization Source for Mass Spectrometry

“…Correspondence to: Mehdi Moini; e-mail: moinim@gwu.edu techniques, such as fast GC and fast LC, as well as supercritical fluid chromatography MS and capillary electrophoresis MS (CE-MS), have been introduced [13][14][15][16][17]. Among these separation techniques, CE is the easiest one to miniaturize since it only requires high voltage power supplies for its operation.…”