A Biosensor-Based Quantitative Analysis System of Major Active Ingredients in Thunb. Using UPLC-QDa and Chemometric Analysis.

In the study, a surface plasmon resonance-based (SPR-based) competitive assay was performed to analyze different compounds' inhibitory activity to TNF-, an important pro-inflammatory cytokine in the pathogenesis of chronic inflammatory diseases. Moreover, the single mass spectrometry (MS) detection method was coupled with an ultra-high-performance liquid chromatography (UPLC) system for the routine quality control (QC) of a traditional Chinese medicine (TCM). The above quality control strategy was evaluated with Thunb. Analytes were firstly separated on a Waters ACQUITYTM UPLC HSS T3 column (2.1 × 50 mm; particle size = 1.8 μm) using a 0.1% formic acid gradient elution, then detected by negative ESI mass spectrometry. The limits of quantification (LOQ) for analytes reached 0.005-0.56 μg/mL. The LOD of the QDa detector was lower than that of the PDA detector, indicating its wider detection range. The QDa detector was also more suitable for the analysis of the complex matrix of TCM. The method showed excellent linearity, with regression coefficients higher than 0.9991. The average recoveries of the investigated analytes were in the range of 98.78-105.13%, with an RSD below 3.91%. The inter-day precision range ( = 3 days) was 2.51-4.54%. Compared to other detectors, this strategy could be widely applied in the quantitative analysis of TCM. In addition, the chemically latent data could be revealed using chemometric analysis. Importantly, this study provides an efficient screening method for small-molecule inhibitors targeting the TNF-α pathway.