Date: Sat, 9 Oct 2010 07:41:52 -0700
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
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From: DAVID KATZ <dakatz45**At_Symbol_Here**MSN.COM>
Subject: Re: Science Education & Safety
In-Reply-To: <00c301cb6722$23f07020$6bd15060$**At_Symbol_Here**vernon**At_Symbol_Here**>

I did a quick and dirty web search for a caffeine extraction that does not use dichloromethane.  I found this ine%20Extraction.pdf  It is by John Thomson at Lane Community College, Eugene, Oregon
I have not tried this procedure and I would be curious to know how well it works.
I do not know the scale at which the class at your university performs this experiment, macroscale, small scale, semi-micro, or micro.  That will also affect the extraction solvent used.  For semi-micro scale or microscale procedures, I agree with Ernie Lippert that students must learn how to work with chemicals such as dichloromethane safely.  That includes the generation of only small quantities of waste product. 
In another experiment, I have my class extracting the fat from potato chips and French fries. Starting with 5 g of chips or 10 g of French fries in a 125-mL flask, I have switched the solvent from dichloromethane to hexane and use several rinsings of 10 mL or less.  The solvent is disposed of in a waste bottle and the chips or fries which are only slightly damp with solvent, in the flask, are dried in a water bath under the hood.  The fat content is determined by the loss in mass.  We get good results.
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