Higher detectability method for the analysis of nucleosides, putative tumor biomarkers, in blood serum samples by CE-UV with reversed EOF.

The development and validation of methodologies for the analysis of biological samples is of outcome importance in order to obtain trustworthy results. This work reports a novel CE-UV method for the assessment of nucleosides, putative tumor biomarkers, in blood serum. The separation of seven nucleosides within c.a. 20 min has been achieved with: BGE 30 mmol/L borate at pH 9.90, 50 mmol/L CTAB, and 10% methanol; V = -10 kV; T = 20°C; and capillary dimensions of 56 cm × 50 μm. The sample plug was concentrated by a modified large volume sample stacking strategy that provided better detectability. Validation showed that the method is suitable for bioanalytical purposes and initial applications in serum samples from healthy subjects are also presented. Finally, statistical methods were applied to verify the effect of characteristics such as age, smoking habits, and alcohol consumption on nucleoside concentrations in blood serum. Univariate statistical analysis tests emphasized the need for age matching, which was confirmed by PCA-DA and PLS-DA. Cancer history in the nearby family may also interfere in nucleoside levels in blood serum, since adenosine concentrations were statistically higher for volunteers who declared having diseased relatives.