Table 2.

Average concentration of nicotine metabolites at various times of day, with and without correction for urine creatinine concentration (coefficient of variation)

Urine metabolite8 a.m. to 12 noon12 noon to 4 p.m.4 p.m. to 8 p.m.8 p.m. to 12 midnight12 midnight to 8 a.m.24 h
Nicotine (pmol/mL)18.4 (0.8)21.1 (1.2)14.5 (1.1)68.1 (1.1)34.7 (1.3)18.3 (0.5)
Nicotine-G (pmol/mL)10.6 (0.5)22.6 (1.2)18.4 (0.9)39.2 (0.7)40.7 (1.1)21.2 (0.5)
Nicotine (pmol/mg creatinine)45.3 (0.9)43.3 (1.1)46.5 (1.0)84.3 (1.1)41.3 (1.2)
Nicotine-G (pmol/mg creatinine)32.2 (0.7)46.5 (0.7)62.3 (1.0)53.9 (0.7)43.1 (0.9)
Cotinine (pmol/mL)58.9 (0.4)63.8 (0.4)49.8 (0.6)81.0 (0.5)74.2 (0.4)62.4 (0.5)
Cotinine-G (pmol/mL)41.5 (0.6)51.4 (0.4)33.9 (0.5)73.7 (0.6)99.3 (0.9)66.7 (0.5)
Cotinine (pmol/mg creatinine)144.9 (0.4)150.2 (0.5)139.8 (0.4)128.6 (0.5)102.9 (0.7)
Cotinine-G (pmol/mg creatinine)109.4 (0.6)126.3 (0.6)121.5 (0.6)103.1 (0.6)98.8 (0.5)
3HC (pmol/mL)97.7 (0.9)104.8 (0.8)73.0 (0.8)135.5 (0.8)209.2 (1.4)118.7 (0.6)
3HC-G (pmol/mL)54.6 (1.6)45.9 (0.9)30.1 (1.1)40.3 (0.6)56.1 (1.2)47.2 (0.8)
3HC (pmol/mg creatinine)198.4 (0.5)210.1 (0.5)186.7 (0.5)194.2 (0.6)193.7 (0.6)
3HC-G (pmol/mg creatinine)97.9 (0.8)107.9 (1.0)87.4 (0.8)71.3 (0.9)59.3 (1.3)
NNO (pmol/mL)28.1 (0.5)52.3 (1.7)36.0 (1.0)72.2 (0.9)54.1 (1.3)30.8 (0.7)
NNO (pmol/mg creatinine)77.9 (0.9)92.2 (1.0)97.3 (1.0)99.4 (0.7)49.4 (1.1)