Why is the Gas chromatography/mass spectrometer the preferred method of choice for determining cocaine?

Question

Why is the Gas chromatography/mass spectrometer the preferred method of choice for determining cocaine?

Answer 1

This technique is extremely sensitive.  Furthermore, it is also very quantitative.  That is, the instrument can both detect small quantities of organic compounds and quantify the amount with high precision.  

I was once an engineer for a company that made these devices.