Table 5.
Reference mass fraction values (mg/kg) for additional analytes in SRM 3672 organic contaminants in smokers’ urine and SRM 3673 organic contaminants in non-smokers’ urine
| SRM 3672(a,b) | (k) | SRM 3673(a,b) | (k) | |
|---|---|---|---|---|
| Creatinine | 734±5 | (2.07) | 505±2 | (2.07) |
| Nicotine(c) | 0.731±0.018 | (2.16) | 0.029±0.002 | (2.36) |
| Ibuprofen(c) | 0.122±0.005 | (2.16) | 0.35±0.002 | (2.36) |
| Caffeine(c) | 2.65±0.05 | (2.16) | 3.58±0.05 | (2.36) |
| Cotinine(c) | 1.09±0.02 | (2.16) | 0.024±0.001 | (2.36) |
| Theobromine(c) | 3.31±0.09 | (2.16) | 5.94±0.15 | (2.36) |
| 3-Hydroxycotinine(c) | 3.46±0.09 | (2.16) | not reported |
(a)
NIST analysis
(b)
The reference mass fraction value is the mean of results obtained using one analytical technique. The expanded uncertainty, U, is calculated as U = kuc, where uc is one standard deviation of the analyte mean, and the coverage factor, k, is determined from the Student’s t-distribution corresponding to the associated degrees of freedom and a 95 % confidence level for each analyte. The effective coverage factor k is given in the table
(c)
Mass fraction of non-conjugated species only