Enhancing instrumental analysis skills through open-ended, problem-solving learning with group investigation

Abstract Instrumental analysis in chemistry education required integration of conceptual understanding with laboratory practice. Multi-step UV–Vis spectrophotometry and Atomic Absorption Spectroscopy (AAS) workflows often expose gaps in procedural fluency and analytical reasoning, especially at decision points for calibration, blank/standard selection, parameter settings, and interference handling. Learning patterns were examined in an undergraduate Chemical Instrumental Analysis course for pre-service chemistry teachers ( N = 90) using an open-ended problem-solving design structured by Group Investigation. Students worked in groups of two to three on instrument-based problems, permitting more than one defensible solution pathway under shared safety expectations. Evidence was triangulated from expert observation of procedural performance, rubric-guided scoring of structured group reports, and a post-instruction conceptual test aligned to UV–Vis/AAS principles and interpretation tasks. Analyses were descriptive and association-based, reporting distributions across indicators, step-to-step workflow coherence, and communication–concept linkages, as well as exploratory profiling and predictive feature ranking for interference handling. Results indicated higher consistency in several UV–Vis indicators than in AAS-related steps, with greater variability concentrated in selected AAS elements and some reporting components. Conclusions were limited to patterns and associations within this course context and did not imply causal effects.