What is the lowest concentration detected by a mass spectrometer?
When checking for narcotics, explosives or illicit drugs at the airport, no dog can compete with what mass spectrometer has been able to do.
Humans have been able to detect 10-18g of Fentanyl with a mass spectrometer. This is only 1,700 molecules of Fentanyl and lowest amount of a material ever detective by a mass spectrometer until now.
To put that in perspective, look at the following scale. It shows the approximate weight of small things. The amount of Fentanyl measured with mass spectrometer is close to small molecular scale. In fact we have been able to detect an amount of Fentanyl that no other machine, sniffer dog or any other technology has been able to reach.
This means that if someone has touched such drug or explosives a year ago, we can still catch them at the airport.