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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: ash2006rf on February 28, 2010, 11:56:56 AM

Title: differentiate between volatile and non volatile compunds
Post by: ash2006rf on February 28, 2010, 11:56:56 AM

may someone help me how can i know this compound is volatile  or not and which rule can i use it to differentiate between the volatile and non volatile one?? :)

Title: Re: differentiate between volatile and non volatile compunds
Post by: Borek on February 28, 2010, 12:13:08 PM

No such (easy) rule and no precise definition of volatile compound - or at least no one that I am aware of. Basically if the pressure of the saturated vapor is high (to be checked in tables, or guessed based on the molecule properties) compound is volatile.

Title: Re: differentiate between volatile and non volatile compunds
Post by: Mr Peanut on February 28, 2010, 03:11:05 PM

Is this an environmental analytical question?

If so, the answer is: it is method defined. If the compound is on the target analyte list for VOCs then it is volatile. If it is on the target analyte for SVOCs then it is semivolatile. Finally, if it has a vapor pressure below that of the SVOC with the lowest vapor pressure in the SVOC target analyte list then you may consider it non-volatile (but this category is not defined within EPA methods).

There is a compound that appears on both lists: naphthalene. It fits the method-definition for both.