Flame Atomic Absorption Spectroscopy (FAAS)
FAAS is widely used for determining metals and metalloids in solution at ppb or ppm levels. Metal ions are converted to the atomic state by nebulization into a high temperature flame. Light of the appropriate wavelength is shone through the flame and the amount of light absorbed is measured against a standard curve. To ensure precision and accuracy of measurements, Type II water with a resistivity greater than 5 MΩ.cm is suitable.
Graphite Furnace Atomic Absorption Spectroscopy (GF-AAS)
GF-AAS uses a small carbon tube rather than a flame to atomize the sample. It is a very sensitive method which is suitable for the measurement of ultra-trace levels of elements, typically below 1 ppb. This means that Type I water would be required for GF-AAS.
ICP-AES or ICP-OES
Inductively Coupled Plasma Atomic (or Optical) Emission Spectroscopy (ICP-AES or ICP-OES) is an analytical technique used for the detection of trace metals and multi-element analysis. Each element has a unique wavelength which is emitted after the atoms are excited, and the intensity of the emission demonstrates the concentration of the element within the sample. Type I water is recommended for this technique.
As water is used to prepare blanks, standards as well as during preparation of the samples, it is important that it remains free from contaminants which could impact on the accuracy and reliability of the results. As the detection limits are below ppb levels, it is important that the water is free from any elements and compounds that may interfere with the results.
Make sure that you are using the right water purity for the technique. While GF-AAS and ICP-AES require Type I water due to the high sensitivity of the analysis, Type II water would be suitable for more general AAS and FAAS.
Make sure that you are using the right water type for your application. Here are the requirements for atomic spectroscopy applications.
|Sensitivity required||Resistivity |
|Bacteria (CFU/ml)||Endotoxins (EU/ml)||Nucleases||Water grade|