Abstract:

Undergraduate experimental courses are a key way to cultivate students’ scientific research practice and innovation abilities. The traditional experimental teaching mode of “emphasizing process and neglecting inquiry” limits the development of students’ scientific research thinking and innovation ability. Especially in the field of analytical chemistry， technical teaching involving techniques such as GC-MS is limited to confirmatory experiments， which is difficult to meet practical needs. In this paper， a comprehensive experimental teaching scheme integrating method development and problem exploration is constructed based on the development of detection methods for pyrimidine fungicides in soil. It covers four links： method establishment， technology optimization， data analysis and extended verification. The teaching method of group cooperation and personal display is adopted to guide students to optimize the relevant parameters of QuEChERS-GC-MS method and encourage them to independently discover and solve problems independently. The results showed that 1% acetic acid acetonitrile （20 mL） was the optimal extraction solvent； 500 mg PSA+500 mg C18+500 mg GCB+1.2 g MgSO₄ was the best purification combination； the linear range of the three fungicides was 0.05-2.0 mg/L， the correlation coefficient was ≥0.995， the LOD was≤0.05 mg/kg and the LOQ was ≤0.167 mg/kg， which was suitable for trace detection. Teaching practice shows that the scheme improves students’ learning initiative and classroom interaction， enhances the quality of experimental reports， lays a foundation for subsequent scientific research experiments， and has important promotion value for the experimental teaching reform of related majors in colleges and universities.

Key words: scientific research ability training, experimental teaching reform, detection of pesticide residues, QuEChERS, gas chromatography-mass spectrometry