Odd silver mirror result

[Practical Magic!]

Tollen's reagent plus propanal/propionaldehyde seems to give a grey, waxy blob on top of the aqueous solution. Anyone seen this before?

 

[Practical Magic!]

I've been struggling with this... Changed all chemicals for fresh but glucose on the left works beautifully but propanal and benzaldehyde both form like lipid looking blobs

 

[Rock Chick]

Nope, never! Our results range from text-book silver mirror to a dirty solution/precipitate in the test tube but never seen a blob of gunk.

 

[Jburns]

I give glucose instead of propanal never seen that before though

 

[ajmc98]

Tollens usually works best on really clean or brand new glassware

 

[Practical Magic!]

I have tried it with a new bottle (2006!!!!) And it did work. But yes I have brand new test tubes and ones washed with NaOH on standby.... Benzaldehyde had the blob effect too!! ‍

 

[Practical Magic!]

I have tried it with a new bottle (2006!!!!) And it did work. But yes I have brand new test tubes and ones washed with NaOH on standby.... Benzaldehyde had the blob effect too!! ‍

Sorry the venus symbol was actually a face palm emoji