Determination of urinary oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine and the association with cigarette smoking.

8-hydroxy-2'-deoxyguanosine (8OHdG) has been widely used as a biomarker of oxidative DNA damage in both animal models and human studies. To evaluate the effect of cigarette smoking on oxidative stress, we studied the levels of urinary 8OHdG from smokers and non-smokers and investigated the association with cigarette smoking. The urinary 8OHdG concentrations were determinated by capillary electrophoresis with end-column amprometric detection (CE-AD) after a single-step solid phase extraction (SPE), and then quantitatively expressed as a function of creatinine excretion. To increase the concentration sensitivity, a dynamic pH junction was used and the focusing effect was obvious when using 30mM phosphate (pH 6.50) as sample matrix. The limit of detection is 4.3nM (signal-to-noise ratio S/N=3). The relative standard deviation (R.S.D.) was 1.1% for peak current, and 2.3% for migration time. Based on the selected CE-AD method, it was found that the mean value of urinary 8OHdG levels in the smokers significantly higher than that in non-smokers (31.4+/-18.9 nM versus 14.4+/-7.6 nM , P=0.0004; 23.5+/-21.3 mug g (-)(1) creatinine versus 12.6+/-13.2 mug g (-)(1) creatinine, P=0.028).

Capillary electrophoresis with end-column amperometric detection of urinary 8-hydroxy-2'-deoxyguanosine.

Urinary 8-hydroxy-2'-deoxyguanosine (8OHdG) is an excellent marker of oxidative DNA damage. Until now, urinary 8OHdG has been measured by high-performance liquid chromatography with electrochemical detection. A simple and sensitive method for the analysis of urinary 8OHdG by capillary electrophoresis with end-column amperometric detection has been developed in our laboratory. A single-step solid-phase extraction procedure was optimized and used for extracting 8OHdG from human urine. To improve the sensitivity of this method, a new focusing technique based on a dynamic pH junction was used. The limit of detection was 20 nM (signal-to-noise ratio S/N = 3), the linear range was 50 nM-10 microM, and the correlation coefficient was better than 0.999. The relative standard deviation (RSD) was found to be 0.57% for migration time, and 4.79% for peak current. To show the usefulness of the method, the urinary concentration of 8OHdG in nine healthy persons and ten cancer patients was determined. The urinary concentration of 8OHdG in cancer patients was significantly higher than that in healthy persons.

[Development of capillary electrophoretic method for determination of the inorganic anions in the ash of black powder].

A capillary electrophoretic method for determining the inorganic anions in the ash of black powder has been developed. The components and pH of the buffer solution, the concentration of osmotic flow modifier and the separation voltage were investigated. The optimized parameters were 5.0 mmol/L sodium chromate buffer solution (pH 8.20) containing 0.5 mmol/L cetyltrimethylammonium bromide (CTAB) as osmotic flow modifier, a separation voltage of -20 kV and a detection wavelength of 254 nm. Under the specified conditions five anions were completely separated in four minutes, and the repeatabilities (RSD) of migration time and peak area were in the range of 0.17%-1.4% and 3.9%-5.0%, respectively. The detection limits were in the range of 5.0 mumol/L to 10.0 mumol/L. To show the usefulness, the method was applied to analyze the ash of a black powder and the results showed that the relative standard deviations of the determination for Cl- and NO2- were 6.0% and 3.9%, respectively.