Infrared Sensor for drug detection
The ir sensor has filters for 8550nm(1169cm^-1), 8750nm(1143cm^-1), 9650nm (1036cm^-1), 12250nm (816cm^-1). Also your typical methane detector is at 3300nm(3000cm^-1) so alot of these line up with the absorbance peaks, do you think this will work as a detector?


That detector is meant for measuring the concentration of a known gas in a purified form.  It works because the measurement is of a known, purified substance.  You need to define both the substance you want to detect and the additional substances you want to be able to exclude.  That determines which and how many wavelengths are needed.  


  I have seen typically for organic compounds that have aromatic rings or pi bonds UV spectroscopy is typically used but i cant seem to find UV detectors online.


There are a lot of companies that sell UV spectrometers online. 


  What is a good estimate of ppm that this ir detector could sense?


The range of PPM that could be detected depends on the instrument using the detector.  With a large volume, ultra-pure sample, and long integration time, you could measure parts per billion or even smaller.  With an impure sample, you won't be able to measure at all.