Conway Microdiffusion
Definition
A two-chamber glass cell in which an acid in the outer ring liberates HCN from the sample and the gas diffuses into a colour reagent in the inner ring. The classical screen for cyanide in viscera.
- Apparatus
- Two-chamber glass diffusion cell
- Mechanism
- Acid liberates HCN, diffuses to colour reagent
- Application
- Screening for cyanide in viscera
Common questions
Why is Conway microdiffusion well suited to cyanide testing in decomposed tissue?+
It isolates the volatile HCN gas by letting it diffuse away from the sample, separating the target compound from a complex, decomposing tissue matrix that would otherwise interfere with a direct colour test.
What normally follows a positive Conway microdiffusion result in casework?+
The colour change is a screening result, so a positive finding is typically followed by a more specific confirmatory and quantitative method, such as headspace gas chromatography.
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