What is the reference method used for trace element analysis?

• A. AAS
• B. ICP-MS
• C. ICP-OES
• D. FAAS

Answer: (A)

Atomic Absorption Spectrometry has long been the reference method for trace element analysis because it provides direct, element-specific quantification with well-established calibration data and broad laboratory familiarity. In AAS, atoms in a flame or a graphite furnace absorb light at a wavelength characteristic of the element, and the amount of light absorbed is proportional to the element’s concentration in the sample. This approach is robust, relatively simple to set up, and has extensive reference data and validated methods for many metals.

For routine and moderate-trace measurements, flame AAS works well, while graphite furnace AAS offers much lower detection limits for ultra-trace levels. Although ICP-MS and ICP-OES are powerful and capable of multi-element analysis with very low detection limits, AAS remains the classic, widely accepted reference method for precise single-element quantification in many standard procedures and laboratories.