New electrochemiluminescent sensing platform based on SnS2 for direct determination of citrulline

• SnS 2 nanomaterial enhances the electrochemiluminescence response. • Disposable citrulline electrochemiluminescent sensor. • Citrulline molecule as analyte and co-reactant simultaneously. Citrulline is a non-essential amino acid involved in the urea cycle and in the production of nitric oxide in many biological systems, therefore its detection and quantification are crucial for the diagnosis and treatment of various diseases. Citrulline is found in organisms, as it is an intermediate in the synthesis of the amino acid arginine, or by dietary intake. In the present work we have developed an electrochemiluminescent sensor for the sensitive determination of citrulline, in which the compound is simultaneously as the analyte and the co-reactant in combination with a nanomaterial, SnS 2 . The use of SnS 2 produces a considerable improvement in the electrochemiluminescent response when [Ru(bpy) 3 ] 2+ complex is used as luminophore. After optimizing the parameters that influence the electrochemiluminescent response, a good linearity (R 2 = 0.998) was found in the range 10 μM–1 mM citrulline, with detection and quantification limits of 2.95 μM and 9.83 μM, respectively. Sensor’s stability and durability studies were carried out and the potentially interfering compounds were analysed. The citrulline content was determined in a food sample, confirming the developed electrochemiluminescent sensor’s viability.