FIA Online Spectrophotometric Determination of Total Flavonoids in Plants and Its Application for Batch Adsorption Kinetics

In this study, we developed a novel approach for the online detection of total flavonoid content (TFC) in plants and their batch adsorption/desorption processes by applying the aluminum chloride colorimetric method for flow injection analysis (FIA). At the optimum experimental conditions, concentration of rutin solution showed good linearity with its light absorption at 420 nm in the concentration range of 10–360 mg/L for the quantification of TFC. Resin screening and adsorption/desorption kinetic tests were performed, and HPD 300 resin was identified as the best suitable adsorbent, and the proposed pseudo-first-order and pseudo-second-order kinetic models can better describe the kinetic parameters of the batch adsorption/desorption process. The sample throughput was 24 per hour, with high reliability [standard deviation (SD) < 0.086]. The FIA method holds significant potential in studying and monitoring adsorption processes due to its capability of automatic online analysis, low reagent and sample consumption, and ability to generate large quantities of highly accurate adsorption data.