I would like to measure carbon isotope composition of CO2 as products of Naphthalene degradation using GC-C-MS. Direct injection of headspace gas would be an straightforward method. However, the starting reactants were prepared as a mixture of Naphthalene with nature abundance and 13C labeled Naphthalene. I was wondering how bad the memory effect introduced by the 13C labeled Naphthalene would be and What are the better ways to get rid of the memory effect (GC column baking/flushing?). I would appreciate hearing your thoughts on this.