In situ Derivatization of Lung Cancer Biomarker Aldehydes by Parallel-DPX-Cork and Quantification by HPLC-DAD

Lung cancer is one of the main causes of death for thousands of people yearly around the world. Biomarker aldehydes, such as hexanal and heptanal, are compounds related to the development of lung cancer, which can be detected in the early stages of this disease. A methodology was proposed to determine these aldehydes in urine, with a new configuration associated with the sample preparation step. A novel strategy with a parallel-disposable pipette extraction (DPX)-cork device was used, offering a fast and affordable extraction methodology with analysis performed by high performance liquid chromatography with diode array detector. In optimization steps, multivariate and univariate designs were applied, providing the following conditions: urine sample centrifuged at 3500 rpm for 15 min, 30 μL and 6 min of dinitrophenylhydrazine impregnation, 10× urine diluted in ultrapure water, pH adjusted to 4.8, 7 extraction cycles with 1.5 min each, 30 mg of cork, 2 desorption cycles and solvent acetonitrile with 300 μL. Limits of detection were 0.13 ng mL-1 for both analytes and limits of quantification were 0.40 and 0.41 ng mL-1 for hexanal and heptanal, respectively. Intraday and interday precisions ranged from 4 to 21%. Relative recoveries ranged from 86 to 107%, assessed at three concentrations. Urine samples were analyzed, but the presence of aldehydes was not detected.