A vehicle exhaust system includes a mixer and a doser that sprays a reducing agent into the mixer to be thoroughly mixed with engine exhaust gases prior to introduction of the mixture into a downstream exhaust component. The organic EL device has an anode layer, an organic light-emitting layer, and a cathode layer. In particular, it relates to compounds that are factor VIIa inhibitors. The method includes producing analyte ions from a matrix based ion source, enhancing the analyte ions with an ion enhancement system and detecting the analyte ions with the detector of the mass spectrometer.