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A novel 14 C‐postlabeling assay using accelerator mass spectrometry for the detection of O 6 ‐methyldeoxy‐guanosine adducts
Author(s) -
Tompkins Elaine M.,
Farmer Peter B.,
Lamb John H.,
Jukes Rebekah,
Dingley Karen,
Ubick Esther,
Turteltaub Kenneth W.,
Martin Elizabeth A.,
Brown Karen
Publication year - 2006
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2370
Subject(s) - chemistry , acetic anhydride , detection limit , adduct , mass spectrometry , accelerator mass spectrometry , liquid scintillation counting , chromatography , guanosine , radiochemistry , analytical chemistry (journal) , organic chemistry , biochemistry , catalysis
Accelerator mass spectrometry (AMS) is currently one of the most sensitive methods available for the trace detection of DNA adducts and is particularly valuable for measuring adducts in humans or animal models. However, the standard approach requires administration of a radiolabeled compound. As an alternative, we have developed a preliminary 14 C‐postlabeling assay for detection of the highly mutagenic O 6 ‐methyldeoxyguanosine (O 6 ‐MedG), by AMS. Procedures were developed for derivatising O 6 ‐MedG using unlabeled acetic anhydride. Using conventional liquid chromatography/mass spectrometry (LC/MS) analysis, the limit of detection (LOD) for the major product, triacetylated O 6 ‐MedG, was 10 fmol. On reaction of O 6 ‐MedG with 14 C‐acetic anhydride, using a specially designed enclosed system, the predominant product was 14 C‐di‐acetyl O 6 ‐MedG. This change in reaction profile was due to a modification of the reaction procedure, introduced as a necessary safety precaution. The LOD for 14 C‐di‐acetyl O 6 ‐MedG by AMS was determined as 79 amol, ∼18 000‐fold lower than that achievable by liquid scintillation counting (LSC). Although the assay has so far only been carried out with labeled standards, the degree of sensitivity obtained illustrates the potential of this assay for measuring O 6 ‐MedG levels in humans. Copyright © 2006 John Wiley & Sons, Ltd.