Sustainable hybrid sorbent based on a thin film gelatin coating over cellulose paper for the determination of steroid hormones in urine and environmental water samples

• Gelatin coated paper is proposed as a novel sorptive phase. • The new material is based on the combination of two natural polymers. • Gelatin deposition changes the interaction chemistry of cellulose. • The new sorbent is evaluated by extracting selected hormones from different samples. Paper-based sorptive phases are cheap, versatile and easy to functionalize materials. Gelatin is one of the most exciting biopolymers because of its biocompatibility, high biodegradability, low price, and high amount of hydroxyl, carboxyl, and amino groups on its network with potential and innovative analytical applications. In this work, a sustainable, simple, low-cost, and effective hybrid sorbent based on the coating of cellulose papers with gelatin has been prepared. Its extraction performance was evaluated using three steroid hormones (estrone, testosterone, and 17 beta-estradiol) as model analytes, which were determined by liquid chromatography coupled to mass spectrometry. The hybrid gelatin-coated papers exhibited high affinity for the target analytes, obtaining higher extraction capacity than that obtained with the individual materials (i.e., raw paper and gelatin without paper support). The preconcentration factors ranged from 3.5 to 8.0. Moreover, the modified papers were stable in aqueous and organic solvents as well as after drying, and they could be reused up to 8 times without decreasing the extraction performance. The sustainable gelatin-coated papers were applied for the determination of the three steroid hormones in human urine and environmental water samples. The limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.04 to 5 μg·L −1 and from 0.1 to 15 μg·L −1 , respectively. The precision of the method expressed as relative standard deviation (RSD) ranged from 5 and 10 %. While steroid hormones were not found in environmental waters, they were detected in the analyzed human urine samples without interference from other endogenous compounds. Moreover, a recovery study was carried out analyzing spiked urine, and water samples yielded recoveries ranging from 76 to 100 % and 71 to 109 %, respectively. These results demonstrate the potential of the new phase for extracting analytes from biological and environmental samples.