Dispersive Liquid–Liquid Microextraction for the determination of urinary 8-hydroxy 2’-deoxyguanosine in COVID-19 patients by Gas chromatography-Mass spectrometry

Abstract

COVID-19 disease has led to many deaths worldwide and early detection of people at high risk of severe cases of this disease would greatly help physicians. The presence of oxidative stress biomarkers may help identify high-risk individuals early in the course of the disease. 8-Hydroxy-2’-deoxyguanosine (8-OHdG) is a widely used biomarker for assessing endogenous oxidative DNA damage. In this study, the urinary 8-OHdG levels were determined in COVID-19 patients and COVID-19 patients with cancer by dispersive liquid-liquid microextraction (DLLME) method using gas chromatography-mass spectrometry (GC-MS). The effects of essential parameters on the extraction method were investigated. LOD and LOQ are equal to 1.7 nM and 5.1 nM, respectively. At varied concentrations of 8-OHdG (300, 400, and 600 nM), the relative standard deviation (RSD) ranged from 18.35% to 22.36%. The mean urinary 8-OHdG levels of cancer and COVID-19 patients were 13.20±6.20 nmol/mmol, while the mean levels in COVID-19 patients and healthy volunteers were 6.67±5.80 nmol/mmol and 1.61±1.72 nmol/mmol, respectively. The results of this study showed that the level of 8-OHdG urine biomarkers in people with COVID-19 is significantly higher than in healthy people. In this study, the DLLME approach was used for the first time to determine the value of 8-OHdG using GC-MS. According to the obtained results, the DLLME method was successfully used as a biomarker of DNA oxidative stress for extracting 8-OHdG urine. Compared to other methods, this technique has advantages such as shorter extraction time and low cost.