Why are high temperature nitrous oxide-acetylene flames sometimes required within atomic absorption spectroscopy?

Why are high temperature nitrous oxide-acetylene flames sometimes required within atomic absorption spectroscopy?

Nitrous oxide can be used as an oxidant gas when hotter flames are required. It has no explosive hazard and temperatures in the range of 3000°C are reached.At such temperatures molecular dissociation of compounds of such elements takes place easily.

Why is nitrous oxide used in AAS?

The propane-butane-nitrous oxide flame and the mixed acetylene-nitrous oxide + air flame have been evaluated for use in atomic absorption spectroscopy. The mixed acetylene-nitrous oxide + air flame is more promising as the envisaged universal flame. It affords a sensitivity high enough for refractory elements.

Why is a nitrous oxide flame needed for the analysis of barium?

The use of a nitrous oxide-acetylene flame vir- tually eliminates chemical interferences in the determination of barium. However, barium is easily ionized in the nitrous oxide-acetylene flame; to control this effect, sodium chloride solution must be added to each sample and standard.

Why is a flame used in atomic absorption spectrophotometry?

In AAS, a solution containing the analyte is introduced into a flame. The flame converts samples into free ground state atoms that can be excited. According to the law, the amount of light absorbed is proportional to the number of atoms excited from the ground state in the flame.

Why acetylene is used in AAS?

Because it gives a very high temperature: 2200-2400 ∘C. This is due to its high heat of combustion, around 1300 kJ/ mol. If still higher temperatures are required, as for Al, Si, Ti, etc., a combination of acetylene and N2O is used, which reaches 2600-2800 ∘C.

What temperature does acetylene gas burn at?

around 4000° F
The heat and temperature produced by an acetylene flame depend upon the amount of oxygen used to burn it. Air-acetylene produces a flame temperature of around 4000° F (2200° C). This is hot enough to solder aluminum work glass, repair radiators and braze plumbing fixtures.

Why is argon used in AAS?

Argon being inert is required in graphite furnace analysis to prevent combustion of graphite tubes at high temperatures. It is used as external and internal gas streams when using graphite furnace or as a carrier gas with mercury/hydride systems.

Why do air and acetylene gases need to use in an AAS?

Which part of the flame is used for atomic absorption in flame atomic absorption spectroscopy?

hollow cathode lamp
After pyrolysis, the furnace is rapidly heated to the atomization temperature to volatilize the analyte into the atom cell. The atomization temperature can be anywhere in the range of a few hundred to about 2700 °C. The analyte then absorbs light from the hollow cathode lamp to give the atomic absorption.

Why is atomic absorption spectroscopy important?

Atomic absorption spectroscopy has become one of the most frequently used tools in analytical chemistry. This is because for the determination of most metals and metalloids the technique offers sufficient sensitivity for many applications and is relatively interference free.

Why is AAS useful for metal analysis?

A major reason for this is that the atoms in metal elements are more easily readable. For AAS to be effective, the atoms in a material must be in isolation and free of possible contaminating lines from molecules. Metals generally have narrow, single emission and absorption lines, which form brightly and clearly.

What gases are used in AAS?

Typical gases used in AAS are Nitrogen and Argon.

What is the name of the flame used in atomic absorption spectroscopy?

WILLIS, J. Nitrous Oxide – Acetylene Flame in Atomic Absorption Spectroscopy. Nature 207, 715–716 (1965). https://doi.org/10.1038/207715a0 Sorry, a shareable link is not currently available for this article.

What is the light source required for FP spectroscopy?

No light source is required since the energy imparted to the atoms comes from the flame. Thus, FP is different from atomic absorption spectroscopy (AA), which is described in the next section. As implied previously, only a very small number of the atoms in the flame are actually present in an excited state at any given instant.

Which AAS instruments can be used for flame only?

Flame AAS ICP-MS AAS instruments can be flame only, furnace only, or combined (switchable) MP-AES ICP-OES Graphite Furnace AAS 2 Today’s Agilent: Atomic Spectroscopy

How to improve the performance of air/acetylene burners?

–Lamp type and alignment •Alignment should be checked – gain setting should be consistent •Lamp type can improve performance e.g. using high intensity UltrAA lamp –Burner •Burner position must be optimized (vertical, horizontal & rotational positioning) •Burner type changes path length (for air/acetylene elements) 7