Strand displacement reaction and gold amalgamation dual-amplified cold vapor generation point discharge atomic emission spectrometry for ultrasensitive acetamiprid determination.

Aptamer-based atomic spectroscopy offers high sensitivity and selectivity but is limited by bulky instrumentation. The integration of aptamer-based sensing with microplasma atomic emission spectroscopy (AES) enables a portable and user-friendly platform for real-time field detection. In this study, a dual-signal amplification chemical vapor generation point discharge atomic emission spectroscopy (CVG-PD-AES) platform was developed for highly sensitive, label-free, and separation-free determination of acetamiprid (ACE). The system integrates strand displacement reaction (SDR) amplification with gold filament preconcentration to enhance analytical performance. A thymine-mercury-thymine (T-Hg2+-T) complex was constructed. Upon ACE addition, the acetamiprid-binding aptamer (ABA) preferentially binds to ACE, releasing target DNA to initiate SDR, which induces Hg2+ release. The released Hg2+ is subsequently reduced to Hg0, selectively enriched through gold filament amalgamation, and detected by a miniaturized CVG-PD-AES system. Under optimized conditions, the method achieved an exceptionally low limit of detection (LOD) for ACE at 96 fg/mL, accompanied by high selectivity arising from specific aptamer-target recognition. The developed portable sensing platform was successfully applied to monitor ACE bioaccumulation in the Mori Folium of cultivated traditional Chinese medicinal (TCM) mulberry trees treated with ACE solutions during growth. The platform demonstrated excellent recoveries in real plant residues and exhibited strong potential for practical field applications.