Determination of chlormequat and mepiquat residues and their dissipation rates in tomato cultivation matrices by ultra-performance liquid chromatography-tandem mass spectrometry

- It is the first study to analysis CQ and MQ residues in tomato cultivation matrices.
- A highly sensitive UPLC-MS/MS method was developed.
- We developed a new method for detecting CQ and MQ in tomato cultivation matrices.

This study described the development and validation of a simple, rapid, specific and sensitive method for detecting chlormequat chloride (CQ) and mepiquat chloride (MQ) residues in tomato cultivation matrices covering soil, water, seedling samples. The dissipation rates of CQ and MQ in tomato cultivation matrices were also determined in this study. A Hydrophilic Interaction Liquid Chromatography (HILIC) column was used for chromatographic separation. A triple quadrupole mass spectrometer equipped with an electrospray ionisation source in positive ion mode by multiple reaction monitoring was used for detection. Soil samples were extracted with accelerated solvent extraction (ASE) and cleaned up with WCX phase extraction column; water samples were extracted with WCX phase extraction column; seedling samples were extracted with methanol-ammonium acetate solution. LODs and LOQs of CQ and MQ were 0.02 μg/kg and 0.1 μg/kg in soil samples, 0.005 ng/mL and 0.02 ng/mL in water samples, and 0.05 μg/kg and 1.0 μg/ kg in seedling samples, respectively. The mean recovery rate of CQ in soil, water and seedling samples ranged from 76.98% to 111.60%. While the mean recovery rate of MQ in soil, water and seedling samples ranged from 96.90% to 105.40%. The fastest to the slowest metabolising rates of CQ and MQ were as follows: soil samples > seedling samples > water samples. In conclusion, this study provided a new potential method for detecting CQ and MQ in tomato cultivation matrices using ultra-performance liquid chromatography-tandem mass spectrometry.