Before I start, I'd just like to note that anything I write here is
for educational purpose only. Neither Google Answers nor I condone or
encourage illegal activities.
With that being said, Dextroamphetamines, a class of amphetamines take
up to 30 hours on a low dose, and up to 120 hours on a high dose. The
urine detection level is about 300ng/mL and it has half life of about
10 hours. Acidic urine enhances excretion, however artifically acidify
urine is not recommended as it can excerbate myoglobinuric renal
failure and/or rhabdomyolysis. It may also serve to concentrate the
Marijuana is a class of cannabinoids. The period of detection is
highly variable. A single use (1 joint) generally requires 24-48 hours
to test negative from urinalysis. One joint/week has detectable level
of cannabinoides 7-34 days after the last dose. A daily user may be
detectable 6-81 days after the last dose. Typical urine detection
levels are about 100ng/mL or for more sensitive instruments, 20ng/mL.
These sensitive instruments may, however, provide false positives as a
result of mere inhalation of marijuana smoke.
If you have any questions, feel free to ask for clarification before
giving a rating. I am willing to work until you are completely
satisfied with the answer to your question.