Acid Blank
Definition
A parallel digestion of reagents in an empty vessel, subtracted from the sample to correct for trace metal contamination in the acids.
- Purpose
- Correct for reagent contamination
- Method
- Parallel digestion in an empty vessel
- Applied to
- Trace metal analysis
- Result use
- Subtracted from the sample reading
Common questions
Why run an acid blank with every batch rather than once per method setup?+
Trace metal contamination in reagents can vary between acid lots and even between digestion runs, so a blank processed with each batch catches contamination specific to that run rather than relying on an old validation figure.
What happens if the acid blank shows an unusually high metal reading?+
It signals contaminated reagents or glassware for that batch, and results from samples digested alongside it are treated as unreliable until the source of contamination is found and the batch is redigested.
Related terms
- Ashing Aid
- A salt (typically magnesium nitrate) added before dry ashing to fix volatile elements as less volatile salts that survive the furnace.
- Dry Ashing
- Viscera or hair is dried and incinerated in a muffle furnace at 450 to 550 degrees Celsius. Inorganic ash is dissolved in...
- Matrix Destruction
- Breakdown of organic tissue into water, CO2 and mineral residue so bound metals are released as free ions. Without it, AAS reads...
- Microwave-Assisted Digestion
- Closed-vessel digestion in PTFE or quartz bombs at 1200 to 1800 W, reaching 200 degrees Celsius and 1500 psi in 30 to...
- Wet Digestion
- Viscera is digested with HNO3 + H2SO4 + HClO4 (or HNO3 + H2O2) at controlled temperature. Closed-vessel microwave-assisted digestion in Teflon bombs...