Multichannel Feeding Module-HPLC Integrated System for Online Species Tracking and Kinetic Analysis

An integrated system comprising a commercial high-performance liquid chromatography HPLC (except autosampler) equipped with an external multichannel autofeeding module was developed to accomplish interference-free separation and kinetic tracking for the H2O2–thiourea reaction, which is proposed as a lab experiment for students who have the background of chemical kinetics. Compared to conventional HPLC, the proposed system: (i) provides a similar pedagogical purpose, where students' knowledge in chemistry can be strengthened and improved and (ii) enables online species tracking and kinetic analysis of reactions with the spectral overlap of multiple species, and other interference factors such as turbidity caused by precipitation formation, bubble requirement, or external excitation light for photocatalysis. Additionally, automation of the proposed equipment allows for saving labor and high efficiency. Based on the reliability and accuracy of the proposed system, different species including reactants, intermediates, and products were simultaneously tracked during thiourea oxidation. Both kinetic curves of multiple species and kinetic parameters obtained provide lots of reliable data for fitting and mechanistic analysis. Because the H2O2–thiourea reaction as a lab experiment successfully performed by students with this technology has proven its operability for undergraduates majoring in chemistry, this proposed method is easy to extend to environmental science, pharmacokinetics, and other fields.