DETERMINATION OF OXIDATIVE DAMAGE MARKERS OF NUCLEIC ACIDS 8-HYDROXYGUANOSINE AND 8-HYDROXY-2'-DEOXYGUANOSINE IN URINE BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY WITH TANDEM MASS SPECTROMETRIC DETECTION

Products of oxidative damage to nucleic acids are considered as relatively stable biomarkers in the diagnosis of negative consequences of oxidative stress. The content of biomarkers of oxidative degradation of DNA (8-hydroxy-2'-deoxyguanosine, 8-OHdG) and RNA (8-hydroxyguanosine, 8-OHG) in biofluids increases when the body is exposed to toxic compounds, radiation and other negative factors associated with oxidative stress. Due to the non-invasiveness of sampling and higher concentrations of target analytes, urine is considered as a priority matrix for biomonitoring the consequences of oxidative stress. A procedure for the combined determination of 8-OHdG and 8-OHG in urine by HPLC-MS/MS has been developed. A structurally similar exogenous compound 8-(1-hydroxybutan-2-ylamino)-1,3,7-trimethyl-1-purine-2,6(3H,7H) was selected as an internal standard. The measurement range for both analytes was set within 1 to 50 ng/mL. To prepare bioassays for analysis, a solid-phase extraction procedure on a hydrophilic-lipophilic sorbent (HLB) in the target substance retention mode was optimized. When using high-resolution HPLC-MS/MS technology, the error of analysis does not exceed 25 % over the entire measurement range. A total of 130 urine samples of chemical plant workers aged 20 to 70 years without diagnosed systemic diseases were analyzed. The 8-OHdG content in the urine samples was in the range of 1 to 20 ng/mL, and 8-OHG — from 2 to 12 ng/mL. The dependence of concentrations of both biomarkers in urine on the age of the worker was established.