Abstract: A fiber-optic urea sensor based on surface plasmon resonance (SPR) and Mach-Zehnder interference (MZI) combined principle was designed and implemented. By plating gold film on the ...

Mouth swab drug tests use a saliva sample to check for the presence of drugs or alcohol. You should not eat or drink for 10 minutes before a mouth swab drug test and make sure nothing is in your mouth ...