Cyclopentanone ethylene ketal

Renunal of ethylene hemithioacetal and -ketal protecting group, 1,3-Oxathiolanes when treated with chloramine-T in water or ethanol under mild conditions give the corresponding aldehydes or ketones in good yields. For example, 1,4-oxathiaspiro-[4.4]nonane (1) affords cyclopentanone (2) in 91 % yield when treated with chloramine-T in 85 % CHjOH-HjO at 25° for 2 min. 

You have attempted to convert cyclopentanone to the corresponding ethylene glycol-ketal derivative. Your NMR is broken down and you cannot use the mass spectrum. Using only IR and any chemical test you like, describe how you can tell whether the reaction worked or not. (Note you cannot use boiling point, melting point, etc.)... 

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