What Is AAS Analysis?
Atomic absorption spectrometry is based on free atoms in the sample absorbing light at their characteristic wavelength. The amount of light absorbed is proportional to concentration. Atomisation is done by flame (FAAS) or graphite furnace (GFAAS); the cold-vapour technique is used for mercury.
Purpose of AAS Analysis
The purpose is to measure a specific element selectively and at low cost. It is a more economical solution than ICP techniques for routine measurements not requiring many elements simultaneously.
Which Products Is AAS Analysis Applied To?
- Metal determination in drinking and utility water
- Minerals such as iron, zinc, calcium in food
- Concentration control in metal plating baths
- Soil and fertilizer samples
- Trace heavy metals in cosmetics
In Which Sectors Is AAS Analysis Used?
Standards Related to AAS Analysis
- ISO 15586 (water quality — determination of trace elements by graphite furnace AAS)
- EN 14082 / EN 14084 (determination of trace elements in food by AAS)
- ASTM D3223 (determination of mercury in water)
AAS Analysis Conditions
- atomization
- Flame (FAAS), graphite furnace (GFAAS) or cold steam — depending on element and concentration
- Lamba
- Separate hollow cathode lamp for each element
- Dalga boyu
- Element specific; defined in the method
- background correction
- Deuterium or Zeeman correction
Equipment for AAS Analysis
- Atomic absorption spectrometer
- Flame unit and gas system
- Graphite furnace unit
- Hydride/cold-vapour apparatus
- Element-specific hollow cathode lamps
Sample Requirements for AAS Analysis
- Solid samples are digested with acid
- The sought element must be stated in advance — the instrument uses a separate lamp for each element
- Usually a few grams or milliliters is sufficient
- Dilution or standard addition may be needed for high-salt matrices
Duration of AAS Analysis
Measurement per element takes minutes. For multi-element requests, time increases in direct proportion to the number of elements; in that case ICP techniques are faster.
AAS Analysis Procedure
- 1The sample is digested and diluted if required.
- 2The lamp for the sought element is installed and the wavelength is set.
- 3Calibration solutions are read.
- 4The sample is atomised and absorbance is measured.
- 5Background correction is applied.
- 6Concentration is calculated from the calibration curve.
- 7A recovery check is performed.
AAS Analysis Acceptance Criteria
A method produces a result; it does not set a limit. Whether the result is acceptable is determined by the regulation or specification the product is subject to.
Evaluation of Results
Results are calculated from the calibration curve. In a laboratory where the method has been validated, linearity, recovery, repeatability and the limit of quantification are established beforehand; the value in the report is meaningful within this validated range.
AAS Analysis Report
- Sample description, receipt date and laboratory number
- Method applied and reference standard, if any
- Instrument and measurement conditions
- Sample preparation steps
- Measurement results and units
- Measurement uncertainty (if requested)
- A statement that the results relate only to the sample submitted for testing
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Regulation on Water Intended for Human Consumption
- EU 2023/915 (contaminants in food)
- Water Pollution Control Regulation
Pages Where This Method Is Used
Analytical Methods — What Does This Group of Methods Do?
The section below describes the field that the AAS Analysis test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Analytical method pages are pages about a MEASUREMENT TECHNIQUE rather than about a test. The difference matters: "salt spray testing" is a test and answers one question; "ICP-MS" is a technique and is used in dozens of different tests. Sometimes the user is looking not for the test but for the technique — because the method name is what appears in their specification.
This distinction becomes decisive in choosing a laboratory. When a customer asks for "heavy metal analysis", the real question is by which technique it will be done: XRF is fast and non-destructive but does not distinguish compounds; AAS is economical for a single element; ICP-OES screens multiple elements; ICP-MS sees trace levels. The same sample gives results with different detection limits and different uncertainties across the four techniques.
Method selection is made against three criteria. DETECTION LIMIT: is the concentration sought within the range the method can see? MATRIX COMPATIBILITY: is the sample matrix (plastic, food, soil, metal) one the method can handle, and is pre-treatment required? SPECIFICATION LINK: does the product standard or legislation mandate a particular method? The third often overrides the first two — the specification binds the method.
Method pages build a CHAIN. A technique is linked to the test pages where it is used, to the standards those tests rest on, to the legislation those standards are tied to and ultimately to market access regimes. The example chain in the source document works like this: XRF → metal analysis → RoHS compliance → heavy metal restriction → coating pages. Whichever link the user enters from, they reach the others.
Sample preparation is the invisible half of the result in this family and is a greater source of error than the technique itself. The digestion method, degree of grinding, extraction solvent and dilution ratio change the result markedly. The same sample on the same instrument gives a different result with different preparation; the definition of the method therefore covers preparation too.
Calibration and verification are the third determining component. An instrument is calibrated with certified reference material, the calibration curve is verified periodically and a control sample is run in each batch. Without these steps, a number produced is not traceable even if the instrument is working correctly.
Method groups in this field
Elemental analysis
ICP-OES, ICP-MS, AAS and XRF. They differ in detection limit, matrix tolerance and multi-element capacity.
Chromatography
GC, GC-MS, HPLC, LC-MS/MS and ion chromatography. It separates a mixture into its components and measures each separately.
Spectroscopy
FTIR, Raman, UV-Vis and optical emission. For material identity, functional group identification and alloy composition.
Thermal analysis
DSC, TGA, DMA and dilatometry. Transition temperatures, composition, decomposition and dimensional behaviour.
Microscopy and imaging
Optical microscopy, SEM-EDS, radiography and tomography. Structure, defects and elemental distribution.
Classical (wet) chemistry
Titration, gravimetry and colorimetry. Used as a reference method and in confirming instrumental results.
Commonly confused in this field
- XRF is a screening tool; it sees elements and does not distinguish compounds. A decision on a restricted compound requires confirmation by wet chemistry.
- The phrase "not detected" is not proof of absence; it is read together with the detection limit of the method.
- The specification binds the method. A technically better method is not accepted if the specification calls for another.
- Sample preparation is part of the result; a report that does not state the preparation is not reproducible.
- Results obtained by different techniques cannot be compared directly; their detection limits and uncertainties differ.
- A method page is not a test page; which method applies to which test comes from the product standard.
Which decisions these results support
- Matching the method written in the specification to the laboratory's scope
- Method selection according to detection limit and matrix compatibility
- Confirming an instrumental result with a reference method
- Eliminating deviations arising from sample preparation
Related Tests
Frequently Asked Questions About AAS Analysis
AAS or ICP-MS?
AAS is economical for one or a few elements. ICP-MS is preferred when many elements or a very low limit of quantification is needed.
What is the difference between flame and furnace AAS?
The flame technique is fast and works at higher concentrations. The graphite furnace can measure much lower concentrations but analysis time is longer.