It could be that Food Black 2 is used but what they have made confidential is the salt that they use to neutralize the dye.? In this case Food black 2 has 4 sulfonic acid groups that need to be neutralized to stabilize it.? Sometimes this is done with Sodium.? It could be they are using something else that they don't wish to disclose.? This does have implications for the GC-MS analysis and sample preparation.? It can make analysis more difficult requiring some kind of acidic work up to remove the salt.
Frank Mashockie