The ability to correctly identify the compounds relies heavily on the technician’s understanding and capabilities. Though computers and libraries can provide valuable information, alone technology cannot determine molecular structure as well as a skilled analyst. GC is not a reliable source for identifying substances as multiple compounds are known to generate the same RT. MS will provide us with specific data. This is why the combination in GC-MS testing allows for the greatest analytical results, providing both retention times and mass spectral data. This data must then be weighed by a knowledgeable analyst in order to define the compounds in question and give conclusive proof for identification.