organic chemistry - How do I extract cyanide from apple seeds?

I'm working on a crime story about cyanide poisoning from apple seeds. I just would like to have an idea of what processes and extraction techniques might be involved in getting cyanide from the seeds. The character is supposed to have access to a high school chemistry lab; so I was thinking equipment and tools that can be found in a typical HS lab. I prefer a detailed answer, step by step, if possible. If not then just generalized terminologies would work.

Answer

1. Forget about the apple seeds, they contain about 1 to 4 mg amygdalin per gramm seeds (DOI).


2. Instead, collect apricot seeds during the right season, the amygdalin content varies though the year and can be as high as 5% of the dry weight of the seed (DOI).


3. It is probably advantagenous to break the husk with a nut cracker, a plier, etc. and cut the softer inner material to smaller pieces.


4. 
   

   Extraction of amygdalin can be performed by

   
   
   
   
   • immersing the material in methanol and subsequent ultrasonification
   
   
   
   • Soxhlet extraction with methanol
   
   
   • reflux extraction in water in the presence of citric acid
   
   
   
   

A comparison of the extraction methods is given here.

Removal of the solvent in vacuum will yield a crude material with significant amounts of amygdalin. You might want to have a look at this article from the Western Journal of Medicine on the toxicity. Here, an $\mathrm{LD_{50}}$ of 522 mg amygdalin per kg body weight was estimated for the oral application to rats. The online resource of the U.S. National Library of Medicine gives a value of 405 mg/kg.

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Further information on the health risk of apricot kernels are provided by of the German Bundesinstitut für Risikobewertung (Federal Institute for Risk Assessment) and the British Committee on Toxicity.

A note in the a German medical journal, Deutsche Ärzteblatt, (PDF) describes a case where boy of four years (110 cm, 18 kg body weight) was given apricot kernels during an alternative cancer treatment. Upon additional treatment with a single dose of 500 mg amygdalin, the kid showed agitation, spasms and the eyes started to roll.

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I'll leave it up to your fantasy as a writer on how to apply the poison, but spicing some marzipan with it might help ;)