Rapid enrichment and SERS detection of fenitrothion and methyl parathion in vegetable and fruit juices using a dual-functionalized microneedle.

Fenitrothion and methyl parathion residues pose significant public health risks. Efficiently extracting and real-time detecting pesticide residues in complex matrices remains challenging. This study presents an ultrafast enrichment and SERS detection approach, achieving rapid analysis of fenitrothion and methyl parathion in vegetable and fruit juices using a dual-functionalized microneedle. A point-of-use SERS-active microneedle was developed with rough silver covered with an Au layer for ultrafast electro-enhanced microextraction (EEM) and sensitive SERS response toward real-time monitoring. Applying a negative electric potential to the dual-functionalized microneedle, pesticide enrichment was accelerated, achieving a tenfold increase in efficiency over traditional static strategy. The EEM-SERS process can be completed in 5 min, with strong correlations noted between SERS intensity and pesticide concentrations (r ²  = 0.940-0.976). The detection limits for fenitrothion and methyl parathion were 1.08-1.88 ppb in celery and orange juice, demonstrating the method's effectiveness for quick in situ pesticide residue detection.