Application of Parallel-DPX for the determination of potential cancer biomarkers in urine samples using cork as natural extraction phase followed by GC–MS

Abstract

Early-stage diagnosis is important to discover possible cancers in the human body. Bioanalytical methods are tools that allow for these studies. Biogenic amines are markers of several cancers in the organism, such as colorectal, lung and pancreatic. In this study, the determination of three important amines, putrescine (Put), spermidine (Spd) and cadaverine (Cad), was proposed. The use of Parallel-DPX-Cork is demonstrated for the first time in this type of application, permitting an effective methodology based on Green Analytical Chemistry (GAC) principles, with separation/quantification by GC–MS in human urine. Multivariate and univariate designs were applied, and the sample was prepared as follows: 10 min for alkaline hydrolysis under agitation with NaOH (2 mol L−1), added in a proportion of 1:8 (v/v) with the sample, at 60 °C, followed by 10 min of centrifugation at 3500 rpm, 5 min for derivatization with chloroformate isobutyl (180 µL), sample pH adjusted at 12; the extraction step was performed using 6 cycles, with 2 mL for each cycle (totalizing 12 mL of sample per experiment) and 25 mg of cork; the desorption step was carried out using 2 cycles with ethyl acetate (300 µL). LODs and LOQs were 15.2 and 50 ng mL−1 for all analytes. Intraday and interday precisions ranged from 2 to 22% and 9 to 28%, respectively. For the relative recoveries, the range was 62% to 130%. Five urine samples, collected from male and female volunteers, were analyzed using the methodology proposed, and the analytes concentrations obtained lower than LOQ and LOD.