salting out
C1/C2technical/scientific
Definition
Meaning
A chemistry process where adding a salt to a solution causes a dissolved substance to precipitate or separate.
In a broader sense, the act of causing separation or purification from a mixture by adding another substance; metaphorically, the process of revealing or isolating something by introducing a decisive factor.
Linguistics
Semantic Notes
Primarily used as a noun phrase (the technique) or a gerund (the process of salting out). The verb form is 'salt out'.
Dialectal Variation
British vs American Usage
Differences
No significant semantic difference. The term is identical in its technical meaning. Spelling follows regional conventions in broader text (e.g., 'behaviour' vs. 'behavior' in surrounding sentences).
Connotations
Purely technical, with no regional connotative variation.
Frequency
Equally low frequency in both varieties, confined almost exclusively to scientific contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
to salt [SUBSTANCE] out of [SOLUTION] (verb)[SUBSTANCE] is salted out (passive verb)the salting out of [SUBSTANCE] (noun)Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “None directly associated.”
Usage
Context Usage
Business
Virtually never used.
Academic
Exclusively used in chemistry, biochemistry, and chemical engineering papers and textbooks.
Everyday
Extremely rare; would only appear in highly specific hobbyist contexts (e.g., soap making, advanced home brewing).
Technical
Core term in laboratory protocols for protein purification, soap making, and some industrial separation processes.
Examples
By Part of Speech
verb
British English
- The researcher will salt out the antibody using a saturated sulphate solution.
- They managed to salt the compound out of the aqueous phase.
American English
- The protocol salts out the protein with high-concentration sodium chloride.
- We salted the polymer out of solution for further analysis.
adverb
British English
- No standard adverbial use.
American English
- No standard adverbial use.
adjective
British English
- The salting-out chromatography technique is highly effective.
- They observed a strong salting-out effect.
Examples
By CEFR Level
- Salting out is a common way to purify proteins in the lab.
- The soap maker explained that salting out helps separate the soap from the glycerol.
- The fractional salting out of plasma proteins using ammonium sulphate remains a foundational technique in biochemistry.
- The team optimised the salting-out conditions to maximise yield and purity of the enzyme.
Learning
Memory Aids
Mnemonic
Think of adding so much salt (salting) to a soup that the fat comes out (out) and separates. That's the core idea: adding salt pushes something out of solution.
Conceptual Metaphor
SEPARATION IS FORCING OUT / PURITY IS ISOLATION. The added salt is an agent that forces the desired substance out of its dissolved state.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid a direct word-for-word translation like 'высаливание вне'. The correct equivalent is 'высаливание'.
- Do not confuse with 'засолка' (pickling) or 'посол' (curing with salt for food).
Common Mistakes
- Using it as a simple verb without 'out' (e.g., 'They salted the protein' is incorrect for this meaning).
- Confusing it with 'salting' in a culinary sense.
- Misspelling as 'saulting out'.
Practice
Quiz
What is the primary purpose of 'salting out'?
FAQ
Frequently Asked Questions
No, they are completely different. 'Salting out' is a chemical separation process, while 'salting' food refers to adding salt for preservation or flavour.
No, it works primarily on substances whose solubility decreases drastically in the presence of high salt concentrations, such as many proteins and organic polymers.
The direct opposite in chemistry is 'salting in', where adding a salt increases the solubility of a substance.
While it's a standard laboratory technique, it's also used in some industrial processes, like soap making and certain chemical manufacturing stages.