SERS determination of hydroxy-α-sanshool in spicy hotpot seasoning: The strategy to restrain the interference of capsaicin and its mechanism

[Display omitted] •The CAP-interfering α-SOH Raman signal in spicy hotpot seasoning is verified.•Enzyme and MOFs are used for anti-CAP interference with a comparison of the effects.•Fe-BTC brings remarkable advantages as CAP affinity and inhibiting behavior.•Interactions among α-SOH, CAP, and Fe-BTC are clarified.•Proposed method is soundly validated in natural sample analysis against interference. Hydroxy-α-sanshool (α-SOH) is the principal ingredient responsible for the numbing sensation in spicy hotpot. However, utilizing surface-enhanced Raman scattering (SERS) to analyze the α-SOH in hotpot seasoning is challenging due to the significant interference of capsaicin (CAP). Therefore, two schemes were proposed to address CAP interference in hotpot seasoning, namely laccase-catalyzed conversion and metal–organic framework (MOF) interaction. Among them, Fe-BTC MOF exhibited significant anti-interference effect and the underlying mechanism is elucidated. The motion of CAP aromatic ring was constrained by steric hindrance and electrostatic interactions of Fe-BTC. Additionally, the interaction between CAP aromatic ring and conjugated triene group in α-SOH was quenched, enhancing the α-SOH SERS signal. The proposed method had a significant anti-interference effect on α-SOH quantification in the presence of CAP, significantly enhancing the α-SOH SERS signal in a range of 0.85 to 4.00 × 107. The linearity and reproducibility of the proposed hotpot seasoning testing method were also validated.