Ratiometric molecularly imprinted electrochemical sensor for the detection of GHRP-6

Growth hormone releasing peptide-6 (GHRP-6), a polypeptide with potent growth hormone secretagogue activity, has wide-ranging applications in medical research and sports science. However, the escalating issues of illegal administration and abuse highlight an urgent need for highly efficient and sensitive detection methodologies. To address the challenge of trace detection of GHRP-6, this study constructs a ratiometric electrochemical sensor, MIP/[APMIm]Br/CS@MWCNTs/GCE, by integrating molecularly imprinted technology (MIT) with electrochemical sensing technology. Thionine (Thi) as an internal reference signal and [APMIm]Br ionic liquid as a functional modifier to establish a dual-signal transduction mechanism. By using the dual-signal ratio (I Fe /I Thi ) to eliminate matrix environmental interference, the sensor achieves a detection limit as low as 1.0 pg/mL, over a linear range of 0.3–80 ng/mL. Notably, it demonstrates the recoveries of 98.1%–104.6% in the presence of 100-fold concentration interferents, with a repeatability RSD of 2.04% and only 6.4% signal degradation after 30 days. These performance parameters represent a significant advancement over conventional detection techniques, establishing a robust platform for trace-level GHRP-6 analysis.