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Product information
4000 MiD® Instructions, V6695
3. Product information
Note:
Only use the device for applications that fall within the range of
the intended use. Otherwise, the protective and safety equipment of the
device could fail.
The 4000 MiD
®
is a compact mass detector system that employs mi-
cro-engineering technology to identify the chemical contents of solu-
tions.
The MiD incorporates technologies patented by Microsaic Systems plc
including; spraychip
®
, vac-chip
™
, and ionchip
®
.
A chemical sample, dissolved in suitable solvents, is introduced into the
spraychip, typically from an HPLC or syringe pump. Gas phase ions are
formed and are introduced into the vacuum chamber through the vac-
chip.
The ions introduced through the vac-chip are then focused using a series
of electrostatic ion optics. The ionchip filters the ions according to their
mass-to-charge (m/z) ratios and directs them to the detection system.
The spraychip ion source
The spraychip is a micro-electrospray ion source. Compared to conven-
tional electrospray ion sources, microspray provides the following advan-
tages:
Increased ionisation efficiency
Lower flow rates, which means analysis of very small sample volumes
(for example, nanolitres) over long periods of time.
Very low solvent consumption and minimum waste, when coupled to a
nano-LC.
Lower voltages are required to provide efficient electrospray.
The spraychip can be coupled to nano-flow systems (without a flow
split) or to traditional LC systems (using a flow splitter).
The vac-chip and ion optics
The vac-chip interface allows the MiD to achieve the operating pressures
required for analysis and it aids transportation of ions from the micros-
pray source into the vacuum system of the MiD.
Behind the vac-chip, there is a series of ion optics: a tube lens, an exit
lens, an ion guide and an inter-quadrupole lens. Ions generated from the
spraychip enter the vac-chip and are focused into the ionchip using the
ion optics.
The ionchip
The ionchip is a micro-engineered quadrupole mass analyser. It functions
like a conventional quadrupole mass analyser, acting as a mass filter,
separating ions in order of their mass-to-charge (
m/z
) ratios. However, it
is about one hundredth the volume of a conventional quadrupole mass
analyser.
Vacuum system
The vacuum system consists of a vacuum chamber coupled to two tur-
bo-molecular pumps, which are backed by a small diaphragm pump. All
vacuum pumps are integrated within the MiD. Unlike conventional mass
spectrometers there are no external, floor-standing rotary pumps. This
