Composition Measuring
Instrument
Dr. Vaishakh Nair
Assistant Professor
Department of Chemical Engineering, NITK
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Exit from column
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Mass Spectrometer Detectors
The material to be analyzed is ionized and passed through the spectrometer with enough
energy.
This ionized beam is now passed through a series of electric or magnetic fields depending
on the type of the sample and its properties. The ions are deflected by the field through
which they are passed through in such a way that the ions with the same mass to signal
ratio will follow the same path to the detector.
These charged and deflected ions are now incident onto a detector which is capable of
distinguishing the charged particles falling on it. Based on the mass spectrum produced by
the charged ions, we can identify the atoms or molecules constituting the sample by
comparing them with known masses or through a characteristic fragmentation pattern.
The four main parts of mass spectrometer : 1. Ionizer 2. Accelerator
3. Deflector 4. Detector
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Light beams or rays that transmits a substance refract at the boundaries of different
substances,
such
as
gas
or
liquid
phases
(Fig.).
Refractive index detection is a detection method that applies the principle of light refraction.
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When only the mobile phase flows on the sample side, the light ray travels straight without
refraction, and both cells are filled with the same mobile phase. When a substance other than
the mobile phase, i.e., an analyte, passes through the sample cell, the refractive index of the
light changes. Since the light rays do not travel straight but are refracted, the slit image on the
photodiode shifts slightly. RID can detect this change of refractive index.
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I is the intensity of
radiation coming out
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