I assume it was just cigarrette smoking right?
Nicotine is metabolised in liver to different compounds and most notable of those is a product called Kotinine. All these are excreted thorugh kidneys and are detectable in urine test.
Plasma half life of nicotine is about 1-4 hours and that of Kotinine is around 7-40 hours.
It means that if you will stop completely smoking around 6 days before screening test, and you do not get exposed to cigarrete smoke passivley, then your blood level of kotinine should be in non smoking range by that time.
Still you have almsot 10 days those should be good enough if you practice strict abstinence from cigarrete active and passive smoking.
Best wishes for your surgery.
2 weeks or 14 days required before non smoking level is attained in the body. Because you di not smoke recently, so if it comes up to almost 14 days till 10th of september, then you should be able to pass the test. That is for blood test.
If urine test is performed, it takes more than that.