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Direct determination of nucleosides in the urine of patients with breast cancer using column‐switching liquid chromatography–tandem mass spectrometry
Author(s) -
Cho SungHee,
Jung Byung Hwa,
Lee Sang Hee,
Lee WonYong,
Kong Gu,
Chung Bong Chul
Publication year - 2006
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.689
Subject(s) - chemistry , chromatography , urine , breast cancer , mass spectrometry , tandem mass spectrometry , liquid chromatography–mass spectrometry , cancer , medicine , biochemistry
We developed an analytical method for a simple, sensitive and simultaneous determination of oxidized nucleosides in urine using column‐switching liquid chromatography–electrospray/tandem mass spectrometry (LC‐ESI/MS/MS). We connected two columns through a six‐way switching valve and effectively separated nucleosides in the urine from the interference by column‐switching liquid chromatography. We monitored separated nucleosides using positive ionization tandem mass spectrometry in selective reaction monitoring (SRM) mode. The calibration ranges of nucleosides were 0.2–100 nmol/mL. The linearity of the method was 0.994–0.999, and the limits‐of‐detection (LOD) at a signal‐to‐noise (S/N) ratio of 3 were 0.1–0.2 nmol/mL. The coefficients of variation were in the range 2.28–11.74% for within‐day variation and 4.36–11.15% for day‐to‐day variation, respectively. To explore the relationship between breast cancer and the nucleosides level in human urine, we measured the concentrations of nucleosides in female patients with breast cancer ( n = 30) and in normal female subjects ( n = 30). The concentration of nucleosides was significantly increased in patients with breast cancer when compared with the normal controls (1‐methyladenosine; p < 0.005, N 2 , N 2 ‐dimethylguanosine; p < 0.01, 5‐hydroxymethyl‐2′‐deoxyuridine; p < 0.001, 8‐hydroxy‐2‐deoxyguanosine; p < 0.001). Therefore, the elevated levels of nucleosides could be used as an important biomarker for breast‐cancer research. Copyright © 2006 John Wiley & Sons, Ltd.