1. A method for detecting and measuring ethyl alcohol in the bloodstream comprising the steps of: providing, an array of sensors adapted to process the pre-perspiratory vapor emanating from a person, the pre-perspiratory vapor containing one or more analytes; each sensor in the array of sensors producing a signal in response to the analytes present; at least one sensor producing an identifiable signal to an analyte of ethanol; and at least two sensors in the sensor array producing a different signal in response to an identical analyte; storing signal patterns corresponding to one or more outputs of the array of sensors in a pattern recognition library; and receiving individual outputs from the array of sensors at a computing device, the array output exhibiting a pattern; comparing the array outputs to the signal patterns stored in the pattern recognition library; and determining a transdermal alcohol content measurement as a function of the comparison.