Atomic Absorption Spectroscopy
Atomic absorption spectroscopy (AAS) is a common technique used in many analytical chemistry protocols, as well as applications requiring a high degree of precision and accuracy, such as food & drug safety, clinical diagnostics and environmental monitoring. Aurora’s TRACE™ Atomic Absorption Spectrometers can analyze the concentration of over 70 different elements in a given sample solution, making them a very valuable instrument in any laboratory environment.
Atomic Absorption Theory
Atomic absorption spectroscopy relies on the Beer-Lambert law to determine the concentration of a particular analyte in a sample. The absorption spectrum and molar absorbance of the desired sample element are known, and each element will preferentially absorb light at a particular wavelength, due to each element having a defined and discrete quantity of energy required to promote its electrons into higher orbitals (excited state). During atomic absorption testing, a known amount of energy is passed through the atomized sample, and by then measuring the quantity of light remaining after absorption it is possible to determine the concentration of the element being measured. The technique behind atomic absorption spectroscopy instruments has a great impact in many different applications, ranging from one of the first instruments that a science student will work with, to an instrument that leading scientists around the world use every day.
Sample Preparation & Analysis
Prior to atomic absorption spectroscopy analysis, some samples must be digested to ensure accurate analyte measurement. This can be performed using the TRANSFORM Microwave Digestion System. The sample is then injected into the AAS manually or using an autosampler.
Aurora’s TRACE AI1200 and TRACE 1300 Atomic Absorption Spectrometers are available with flame, graphite furnace and vapor hydride generation atomizers. These atomizers aspirate the sample into the light path where it is illuminated by a hollow-cathode lamp (HCL), which emits light at the wavelength characteristic of the desired elements. A built-in detector measures the light emissions both in presence and absence of sample, and the ratio of the absorbances are used to determine the analyte concentration.
Background correction techniques, such the built-in self-reversal Smith-Hieftje correction method and deuterium background correction adjust for molecular absorption overlap which would otherwise result in incorrect concentration measurements. Both Deuterium and Smith-Hieftje background correction are standard features offered TRACE Atomic Absorption Spectrometer, ensuring consistently reliable measurements.
Vapor Hydride Generation
Vapor hydride generation allows for the determination of mercury and hydride-forming elements such as arsenic and lead by atomic absorption spectroscopy. This feature is available on all TRACE and LUMINA spectrometers or by adding Aurora’s Vapor Hydride Generator to AAS, AFS, ICP-AES and ICP-MS instruments offered by other manufacturers.
Aurora’s Vapor Hydride Generator provides enhanced sensitivities, reduced interferences and extremely low detection limits for the determination of sub-trace levels of mercury and hydride-forming metals. The revolutionary design allows for optimal performances for hydride and cold vapor determinations. This is essential, as it is of utmost importance, especially in fields such as food and water safety that the presence of heavy metals be determined accurately and precisely.
A wide range of industry sectors and applications rely heavily on atomic absorption spectroscopy. These include drug research and design, metallurgy and mining industries, petroleum industries, health and medical services, forensic science, clinical diagnostics, food safety, agriculture, and environmental monitoring.