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Introduction
Advantages of Nanoelectrospray
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EASY-Spray Series Ion Source User Guide
Thermo Scientific
Advantages of Nanoelectrospray
The use of electrospray ionization (ESI) has evolved as a leading technique for generating
intact, gas-phase ions from thermally labile, polar analytes in solution. In this technique, an
emitter (a capillary tube or needle) induces ionization at a controlled distance from a counter
electrode. Direct current (dc) voltage is applied, either to the needle or to the solvent, to
produce a strong electrical field at the emitter tip. The electric field excites the ions in the
solution as they leave the emitter tip. This interaction results in electrohydrodynamic
disintegration of the fluid, generation of droplets, and formation of an aerosol jet.
Conventional ESI employs flow rates from 1 μL/min to 1 mL/min. Expediting desolvation
and droplet shrinkage often requires a drying gas, thermal heating, or both, due to the high
volume of liquid that exits the emitter. Nanospray ionization (NSI), also known as
nanoelectrospray ionization (nanoESI or NSI), is a form of ESI that employs low flow rates of
10 to 1000 nL/min. NSI (or nanoESI) generally does not require a drying gas or thermal
heating. Compared with ESI, NSI tolerates a wider range of liquid compositions including
pure water.
As you lower the flow rate, a lower volume of mobile phase passes through the emitter,
producing smaller aerosol droplets. This makes NSI more effective than conventional ESI at
concentrating the analyte at the emitter tip, which produces significant increases in sensitivity
as demonstrated by the signal response of the MS.
Functional Description
This section describes the following principal components of the EASY-Spray Series ion
source and their functions:
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•
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Note
The MS’s instrument control applications use the terms
nanospray
and
NSI
.
