Atomic Absorption and Emission Spectrometry

Comprehensive vocabulary flashcards covering atomic absorption and emission spectrometry, instrumentation components, flame properties, and various types of interferences.

Atomic absorption

A method that measures the concentration of atoms of an element by passing light, emitted by a hollow cathode lamp of that element, through a cloud of atoms from a sample.

Atomization

The process where the analyte in a sample is converted to its elemental state (gaseous atoms).

Nebulization

The process of spraying a solution of the sample using a gaseous mixture of an oxidant and a fuel into a mist or aerosol before it enters the flame.

Flashback

A condition in flame AAS that occurs if the gas flow rate does not exceed the burning velocity, causing the flame to propagate back into the burner.

Interzonal region

The zone of the flame most widely used in AAS because it is rich in free atoms that can absorb radiation from the source and be excited.

Laminar flow burner

A burner design that provides a relatively quiet flame to increase reproducibility and a long path length to increase sensitivity.

L'vov platform

A small plate of solid pyrolytic graphite inserted into a graphite tube that isolates the sample from tube walls to allow more reproducible atomization through indirect heating.

Limit of detection (LOD)

The lowest quantity of a substance that can be distinguished from the absence of that substance, such as a blank value.

Chopper

A mechanical device used in AAS to modulate light (switch it on and off rapidly) to differentiate light from the source lamp from emission from the flame.

Hollow Cathode Lamp (HCL)

The most commonly used line source in AAS, consisting of a glass tube containing a cathode made of the metal to be determined, an anode, and a noble gas like $Ar$ or $Ne$.

Sputtering

The process in an HCL where ionized gas atoms are accelerated into the cathode, knocking off metal atoms from the cathode surface.

Interference

A phenomenon that leads to positive or negative changes in the intensity of the analyte signal in spectroscopy.

Spectral interference

Interference caused by the presence of another atomic absorption line or a molecular absorbance band close to the spectral line of the element of interest.

Matrix interference

Non-spectral interference occurring when sample properties like viscosity or surface tension differ from the standard, affecting the nebulization efficiency.

Chemical interference

Interference that occurs if a sample contains a species which forms a thermally stable compound with the analyte that is not completely decomposed by the flame energy.

Refractory elements

Elements such as $Ti$, $W$, $Zr$, $Mo$ and $Al$ that can combine with oxygen to form thermally stable oxides requiring higher flame temperatures for dissociation.

Ionization interference

A phenomenon common in hot flames where excess energy leads to the ionization of ground state atoms, reducing the number of available atoms for absorption.

Ionization suppressant

An easily ionized element like $K$, $Rb$, or $Cs$ added to samples to create a large number of free electrons and prevent the ionization of the analyte.

Atomic emission spectrometry (AES)

A technique using the intensity of light emitted from a flame, plasma, arc, or spark at a particular wavelength to determine the quantity of an element.

Plasma

A hot, partially ionized gas containing cations and electrons, used as an atomizer in emission spectrometry.

Inductively coupled plasma (ICP)

An atomizer for AES consisting of three concentric quartz tubes surrounded by a radio-frequency induction coil, capable of reaching temperatures up to $10000\,K$.

Tesla coil

The component used to initiate plasma formation in an ICP torch by providing a spark.