9 theme: Atomic spectrometry in fuel analysis Flashcards
Hollow cathode lamp (HCL) is a radiation source (a light source) in AAS (atomic absorbtion spectrometry). Its limitations is that…..
Typically designed to measure one element at a time.
Hollow cathode in HCL is made of the metal to be determined. Is it true?
yes
how is radiation being released in the Hallow Cathode Lamp? (HCL)
When gas ions (like neon or argon) hit the cathode, they knock out metal atoms from the cathode surface.
These metal atoms absorb energy from collisions with electrons and become “excited” (higher energy state).
The excited metal atoms quickly return to their normal (lower energy) state.
During this process, they release the extra energy as light (radiation) at specific wavelengths unique to that metal.
Is it true that superlamp’s working principle is similar to HCL?
true
Name all AAS possible radiation sources?
Hollow cathode lamp, Electrodeless discharge lam, superlamp
What is an atomizer?
a device that converts the determined element into an atomic pair (free atoms).
what are 2 types of atomizers?
flame and electrothermal
What is the main difference between flame and electrochemical atomizers?
difference lies in how they convert a sample into free atoms for analysis:
flame: Use a flame (usually a mixture of fuel and oxidant like air-acetylene) to vaporize and atomize the sample.
electrochemical: Use an electrically heated furnace (like a graphite tube) to vaporize and atomize the sample.
is flame atomizer more sensitive than electrochemical atomizers?
No, Electrochemical atomizers are significantly more sensitive, making them ideal for detecting very low concentrations of elements (trace analysis).
What is dispersion element and why its needed in AAS?
Dispersion elements refer to components in an optical system (such as in spectrometers) that are used to separate light into its individual wavelengths or spectral components.
FE: MONOCHROMATORS
Monochromators are critical in AAS because they isolate the specific wavelength absorbed by the target element, reducing interference, improving accuracy, and ensuring precise quantification of the element in the sample.
What is the most populary used detector in AAS?
photomultiplier
what are detectors used for in AAS?
Measure Absorbed Light (By comparing the intensity of light before and after passing through the sample, the amount of light absorbed by the sample is calculated.)
Determine Element Concentration (The absorption of light is directly proportional to the concentration of the target element in the sample)
Convert Light Into Electrical Signal
Optical emission spectrometry (OES) is equivalent to atomic emission spectrometry (AES).
true
In flame emission spectromery, the sample is introduced into the flame in the form of an
aerosol.
true
Flame emission spectrometry (FES) can be applied
elements of groups I.A and II.A with low levels of excitation energy
