2. Cold Hg Vapor Technique
Hg2+ + Sn2+ → Hgo + Sn4+
The elemental Hg is swept from the flask into a long path absorption cell in the path of a Hg HCL.
With a 50 mL sample, LOD is 20 ng/L (20 pg/mL)

6. Hydride Generation NaBH4 is added to form hydride
Works with As, Se, Te, Sb, Bi, Sn, Ge.
The hydride is decomposed to atoms in a flame, or a heated quartz cell.
LOD about 0.1 – 1 ppb – similar to furnace

9. Advantages
Some of the hydride-forming elements have resonance lines at very short wavelength (eg As and Se, below 200 nm)
At these wavelengths, conventional flames absorb much radiation.
Therefore flame fluctuates →Noisy signals
The diffusion (low temperature) flames used to decompose hydrides are transparent at the low wavelengths. The heated quartz cell is even better.

11. Additional Advantages
Interferences are often reduced
They are left behind when the hydride is swept away
Therefore you can analyze more complex samples –
viscous
High salt content
High suspended solids