Table 2. Detection Limits (LOD) of DNA Adduct Analyses Using Two Different Eluent Systems for UPLC-MS/MS.
| LOD
(adducts per 108 nucleosides)a |
||
|---|---|---|
| adduct | HOAc/FAb | NH4HCO3b |
| 1,N6-εdAc | ||
| 3,N4-εdCc | ||
| M1dG | 0.63 | 0.43 |
| N2-FFM-dG | 1.6 | 0.59 |
| N6-FFM-dA | 0.62 | 0.11 |
| N2-MF-dG | 0.14 | 0.09 |
| N6-MF-dA | 0.10 | 0.04 |
| N2-MIE-dG | 1.2 | 0.55 |
| N6-MIE-dA | 0.11 | 0.31 |
| N2-1MIM-dG | 1.8 | 0.35 |
| N6-1MIM-dA | 2.2 | 0.51 |
| C8-PhIP-dG | 3.0 | 7.1 |
| C8-ABP-dG | 0.10 | 0.04 |
| N2-BPDE-dG | 1.0 | 3.0 |
| N2-MP-dG | 0.1 | 0.28 |
| N6-MP-dA | 0.01 | 0.02 |
a
LODA = X̅A + 3σA with σA as the mean area of the background signal at the retention time of the analyte adduct in a digest of 350 μg of unmodified DNA and σA as the standard deviation from measurements of five independent samples.
b
HOAc/FA: eluent solvents water (A) and acetonitrile (B), each acidified with 0.25% acetic acid (HOAc) and 0.25% formic acid (FA); NH4HCO3: eluent solvents 10 mM ammonium bicarbonate buffer, pH 8.0, (A) and methanol (B).
c
Sizeable peaks in the traces m/z = 276.1 → 160.0 and m/z = 252.1 → 136.0 at the retention times of [15N5]1,N6-εdA and [15N3]3,N4-εdC, respectively, indicated that the etheno adducts abound in DNA of herring sperm and porcine liver used as biological matrices.