Abstract: To establish an analytical method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of residues of 50 plant growth regulators (PGRs) in Asparagus densiflorus, and to apply it to screen commercially available samples, the samples were pretreated using a modified QuEChERS method and analyzed by UPLC-MS/MS. Accurate quantification was achieved using an internal standard method and matrix-matched calibration curves. The method demonstrated good linearity in the range of 0.5-200.0 μg/L(R²>0.990), with limits of detection (LOD) between 0.02 and 10.00 μg/kg. The spiked recoveries ranged from 67.3% to 125.3%, with all relative standard deviations (RSD) below 5.5%. Analysis of 21 batches of commercial Asparagus densiflorus using the established method revealed that abscisic acid and sodium p-nitrophenolate were 100% detected, with the detection rates of 3-indoleacetic acid and enadenine reaching 95.2% and 76.2%, respectively, while the other plant growth regulators (PGRs) were not detected. In conclusion, the developed method was efficient and reliable, suitable for the high-throughput screening of multiple PGRs classes in Asparagus densiflorus, and provided a technical basis for relevant quality monitoring.

Key words: Asparagus densiflorus, PGRs, UPLC-MS/MS, abscisic acid