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Flame Excitation Source

Introduction

A flame provides a high-temperature source for desolvating and vaporizing a sample to obtain free atoms for spectroscopic analysis. In atomic absorption spectroscopy ground state atoms are desired. For atomic emission spectroscopy the flame must also excite the atoms to higher energy levels. The table lists temperatures that can be achieved in some commonly used flames.

Temperatures of some common flames
FuelOxidantTemperature (K)
H2Air2000-2100
C2H2Air2100-2400
H2O22600-2700
C2H2N2O2600-2800


Instrumention

The figure shows a total consumption burner in which the sample solution is directly aspirated into the flame. This flame design is common for atomic emission spectroscopy. All desolvation, atomization, and excitation occurs in the flame. Other flame designs nebulize the sample and premix it with the fuel and oxidant before it reaches the burner. Atomic-absorption instruments almost always use a nebulizer and also use a slot burner to increase the path length for the sample absorption.


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