[tdod]

I know pure water shows up at 3650, but what about when water is an impurity in the product (i.e. phenyl ketone). Is it realistic for water to stretch as low as 3300 or as high as 3850?

[zsinger]

Perhaps use a condensing column to separate the individual species…..run them each on an NMR, and see what you get.  Honestly, thats the way I like to approach problems such as this in a manner which starts at its elemental parts, and builds to a solution…(just perhaps).  Just my .02.  Check for averages, and concurrent unit shifts (PM me if you would like further explanation on that…..how my Chem PhD mentor taught me…..not hard, but wordy…..makes the most sense IMO). 
            -Zack

[Corribus]

Because of hydrogen bonding, the OH-stretch of water is very broad.  Unless you do something to narrow the peak, it's probably unlikely you will be able to detect a shifts due to impurities using IR spectroscopy.  Maybe not impossible, but it will probably be hard.