Flame photometry, or flame atomic emission spectrometry (FAES), is subject to various interferences that can affect the accuracy and precision of measurements.
These interferences in flame photometry can be broadly categorized as:
1. Spectral Interferences:
Arise when the emission lines of two different elements overlap, making it challenging to distinguish between them.
Can be minimized using narrow-bandwidth filters or monochromators.
2. Chemical Interferences:
Result from the chemical composition of the sample or the flame, affecting the atomization or excitation of the analyte.
For instance, the presence of certain anions or molecules can form stable compounds with the analyte, reducing its atomization in the flame.
Adjusting the flame composition, temperature, or using releasing agents can help mitigate such interferences.
3. Ionization Interferences:
Some elements, especially alkali metals, can get ionized in the flame, which reduces the number of neutral atoms available for excitation.
This interference can be minimized by reducing the flame temperature or adding ionization suppressors.
4. Physical Interferences:
Factors such as viscosity, surface tension, and refractive index of the sample solution can affect the efficiency of nebulization and hence the number of atoms introduced into the flame.
Dilution, using surfactants, or matching the physical properties of standards and samples can help overcome these interferences.
5. Matrix Interferences:
Differences in the overall composition of samples and standards can affect atomization or emission efficiency.
The use of internal standards or the method of standard additions can help correct for matrix effects.
6. Background Emission:
The flame itself might produce some background emission, which can interfere with the analyte's signal.
This can be minimized using background correction techniques or by selecting a different observation height above the burner.
For accurate and reliable results in flame photometry, it's crucial to recognize potential interferences and apply appropriate correction or compensation techniques.