What is chopper in atomic absorption spectroscopy?

A chopper is a spinning wheel that alternately lets source light through to the flame and then blocks the source light from reaching the flame. When the chopper blocks the source, the detector only reads the background flame noise. When the chopper lets the light through, both flame noise and source noise is detected.

What is the purpose of the chopper in an atomic absorption spectrophotometer?

The function of the chopper is to chop the light leaving the source so that when the incident beam hits the chopper at the solid surface, the beam will be blocked and detector will only read the emitted signal from the flame.

What are three common uses of atomic absorption spectroscopy?

Atomic absorption spectrometry has many uses in different areas of chemistry such as clinical analysis of metals in biological fluids and tissues such as whole blood, plasma, urine, saliva, brain tissue, liver, hair, muscle tissue. Atomic absorption spectrometry can be used in qualitative and quantitative analysis.

What causes atomic absorption?

The flame (thermal energy) causes the atom to undergo a transition from the ground state to the first excited state. When the atoms make their transition, they absorb some of the light from the beam. The more concentrated the solution, the more light energy is absorbed!

Which of the following is the principle of atomic absorption spectroscopy?

Atomic absorption spectroscopy (AAS) is based upon the principle that free atoms in the ground state can absorb light of a certain wavelength. Absorption for each element is specific, no other elements absorb this wavelength.

What are the components of AAS?

The standard AAS instrument consists of four components: the sample introduction area, the light (radiation) source, the monochromator or polychromator, and the detector (figure 1).

What is the method for atomic absorption spectroscopy?

Atomic absorption spectrometry (AAS) is a technique in which free gaseous atoms absorb electromagnetic radiation at a specific wavelength to produce a corresponding measurable signal. The absorption signal is proportional to the concentration of the free atoms present in the optical path.

What kind of optics do Atomic Absorption spectrophotometers use?

Atomic absorption spectrophotometers use the same single-beam or double-beam optics described earlier for molecular absorption spectrophotometers (see Figure 10.3.2 and Figure 10.3.3 ). There is, however, an important additional need in atomic absorption spectroscopy: we first must covert the analyte into free atoms.

How does an atomic absorption spectroscopy burner work?

The burner is mounted on an adjustable stage that allows the entire assembly to move horizontally and vertically. Horizontal adjustments ensure that the flame is aligned with the instrument’s optical path. Vertical adjustments adjust the height within the flame from which absorbance is monitored.

How are atomic absorption and atomic emission measured?

Emission vs. Absorption All modern Perkin-Elmer atomic absorption instruments are capable of measuring both atomic absorption and atomic emission. It is important for the operator to understand the processes that occur in each technique. Every element has a specific number of electrons associated with its nucleus.

How is atomic absorption spectroscopy used to characterize NMS?

Atomic absorption spectroscopy (AAS) is another technique that can be used to characterize NMs in terms of elemental composition. For example, a known amount of CdSe/ZnS core/shell QDs can be used to determine the concentration of cadmium and zinc.