Hello forumists

I am hoping to get some help to find out what materials that are common for all cell phones. I am training my K9 to locate cell phones, and plan to use him to search for illegal cell phones in correctional facilities. In order to do this training methodically and reliable, I need to know what odors that are unike for cell phones.

This is what I have found out for myself: Almost all cell phones use a Li-Ion battery. All Li-ion batteries use ethylene carbonate as an organic solvent. This solvent stays the same independent from the charging status, and may be one of the substances that are common for most cell phones.

But training my dog to find etylene carbonate, will also make it locate other consumer electronics that use this type of battery.

Is there an substance only used in cell phones? The screen, the antenna, the circut board etc?

I am greatful for all help here,
Please move this post if I have posted it in the wrong forum.

Regards Aalstad