GFAAS
Definition
Graphite-furnace AAS, also called electrothermal AAS. A graphite tube heated electrically through a programmed ramp atomises a microlitre aliquot, giving roughly 100 times the sensitivity of flame and reaching ppb in biological matrices.
- Sensitivity
- 100 times more sensitive than flame AAS; reaches ppb detection limits
- Sample size
- Uses microlitre aliquots (very small volumes)
- Temperature
- Graphite tube heated to approximately 2700 degrees Celsius
- Best for
- Heavy metals in biological matrices (blood, tissue, etc.)
Common questions
How does GFAAS differ from regular flame AAS?+
GFAAS uses a graphite tube heated electrically to about 2700 degrees Celsius, while flame AAS uses a flame. GFAAS is roughly 100 times more sensitive, reaching ppb (parts per billion) levels. This makes it better for detecting very small amounts of heavy metals in samples.
What metals can GFAAS detect?+
GFAAS works well for detecting arsenic, lead, cadmium, and mercury in biological samples. It can identify these elements at extremely low concentrations that would be missed by less sensitive methods.
Why use such high temperatures in GFAAS?+
The graphite tube is heated to atomise the sample into individual atoms. Atomisation converts the sample into a form that can absorb light at specific wavelengths, which is what the instrument measures to identify and quantify elements.
Related terms
- AAS
- Atomic absorption spectrometry. Free ground-state atoms in a vapour absorb a characteristic resonance wavelength from a hollow-cathode lamp, and Beer-Lambert converts the...
- Background Correction
- A method (deuterium continuum, Zeeman effect, Smith-Hieftje self-reversal, or high-resolution continuum-source) that subtracts non-atomic absorption (molecular bands, scatter) from the raw absorbance...
- CRM
- Certified reference material. A matrix-matched material of known composition (NIST SRM 955c lead in caprine blood, SRM 1577c bovine liver) used to...
- CVAAS
- Cold-vapour AAS. Mercuric ions are reduced by stannous chloride or sodium borohydride to elemental mercury vapour, swept by argon into a quartz...
- HG-AAS
- Hydride-generation AAS for hydride-forming elements (As, Sb, Se, Bi, Te, Sn, Ge). Sodium borohydride in acid generates the volatile hydride, which is...
- Hollow Cathode Lamp (HCL)
- A sealed lamp whose cathode is made of the element being analysed, filled with argon or neon at low pressure. Strikes a...
- ICP-MS
- Inductively coupled plasma mass spectrometry: the laboratory reference method for trace element quantification in food matrices. Uses high-temperature argon plasma to atomise...
- ICP-OES
- Inductively coupled plasma optical emission spectrometry: the plasma excites atoms which emit element-specific wavelengths of light on returning to ground state; suited...
- Ion Chromatography
- Ion-exchange separation with conductivity detection after a suppressor, used to quantitate inorganic anions and cations such as fluoride, oxalate, sodium and calcium.
Explained in these topics
- Atomic Absorption Spectrometry: Flame, Graphite Furnace, Cold VapourGraphite-furnace AAS, also called electrothermal AAS. A graphite tube heated electrically through a programmed ramp atomises a microlitre aliquot, giving rough...
- Inorganic Poison Analysis: AAS, ICP-OES, ICP-MS and Ion ChromatographyGraphite-furnace AAS. A graphite tube electrothermally heated to 2700°C atomises a microlitre aliquot, giving ppb detection for As, Pb, Cd and Hg in biological...