A gas turbine engine axial compressor vane is disclosed having an aperture capable of flowing a relatively high pressure working fluid to change a direction of a flow vector downstream of the vane. These devices are used to test for a variety of analytes, such as drugs of abuse, hormones, proteins, urine or plasma components and the like. The invention also includes a device that embodies the method described above. The instructions also cause the system to receive a second authentication attempt and increment the counter only if validation of the second authentication attempt against the credential verifier fails and the second authentication attempt is distinct from the first authentication attempt. In preferred embodiments, one of R2 or R3 is valine, leucine, isoleucine or alanine, particularly valine.