[xsl] How to remove a single quote?

["dvint@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

I have content like this:

<topic file="fs_task_with_collapse_in_tabs.dita"
	title="FORMAT: task inside a tab using collapsed sections"
	chunk="child"
        tabtitle="'Collapse Sections'">

Notice the single quotes in the tabtitle attrbiute. I would like to get 
just the text out of that attribute without the quotes. I've been trying 
to use substring-before/after like this but I get no result

<xsl:attribute name="tabtitle" select="substring-after(@tabtitle, 
'&apos;')"/>

I'm getting an unmatched quote message and if I switch to ''' I get the 
same message. I thought the entity would escape this. If I use &quot;, I 
don't get the error, but my result is empty as that character doesn't 
exist.

What is the proper way to escape and match a ' ?

..dan