Breath analysis is a convenient and non-invasive way to detect chemicals in a bodily system such as alcohol content to determine intoxication, monitor the levels of anesthetics in the body during surgical procedures, and identify performance-enhancing substances in the system of athletes.  However, conventional techniques are ineffective at low concentrations.  An electrospray ionization interface assisted by an ion funnel used in a linear trap quadrupole Fourier-transform ion cyclotron resonance mass spectrometer was shown to greatly increase sensitivity with high resolution.