Monolithic graphene oxide/polyaniline-coated natural rubber foam for solid-phase extraction of carbamate pesticides in fruit juice samples.

A monolithic natural rubber foam incorporated with graphene oxide (GO) and polyaniline (PANI) was developed as a solid-phase extraction (SPE) sorbent for the determination of carbamate pesticides prior to HPLC-DAD analysis. The sorbent was prepared via latex foaming, followed by GO incorporation and in situ polymerization of PANI, producing a hierarchically porous structure with enhanced surface functionality. The synergistic combination of GO and PANI provided multiple interaction mechanisms, including π-π interactions and hydrogen bonding, resulting in improved adsorption efficiency. The open-cell foam structure enabled low backpressure and high flow-rate operation compared to conventional particle-packed SPE cartridges. Under optimized conditions, the method showed good linearity over 0.25-100.0 μg L-1 (R2 > 0.995). Limits of detection (S/N = 3) ranged from 0.25 to 0.75 μg L-1. Intra-and inter-day precision were below 3.1%. The analytical recovery (AR) from spiked fruit juice samples ranged from 84.1 to 97.1%. Enrichment factors (EFs) in the range of 8.4-9.6 were obtained. The sorbent exhibited good batch-to-batch reproducibility with relative standard deviation (RSD) values below 6%, and could be reused for at least six extraction cycles without significant performance loss. The proposed monolithic rubber foam@GO@PANI sorbent offers a reusable and low-backpressure alternative for trace-level determination of carbamates in complex food matrices.