ABSTRACT
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 0.02µg/kg and 0.1µg/kg in soil samples, 0.005ng/mL and 0.02ng/mL in water samples, and 0.05µg/kg and 1.0µg/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.
Subject(s)
Chlormequat/analysis , Chromatography, High Pressure Liquid/methods , Drug Residues/analysis , Piperidines/analysis , Soil/chemistry , Solanum lycopersicum/chemistry , Tandem Mass Spectrometry/methods , Agriculture , Chlormequat/chemistry , Chlormequat/isolation & purification , Limit of Detection , Linear Models , Piperidines/chemistry , Piperidines/isolation & purification , Plant Growth Regulators/analysis , Plant Growth Regulators/chemistry , Plant Growth Regulators/isolation & purification , Reproducibility of Results , Seedlings/chemistry , Solid Phase Extraction/methodsABSTRACT
A rapid method for analyzing trace levels of chlormequat (CQ) in meat samples by hydrophilic interaction liquid chromatography (HILIC)-electrospray tandem mass spectrometry was developed. The samples were extracted with acetonitrile, followed by a rapid cleanup through a dispersive solid-phase extraction (DSPE) technique with octadecyl (C18) DSPE sorbents. The chromatographic separation was achieved within 6 min using a HILIC column with 10 mM ammonium acetate and 0.1% (v/v) formic acid in water/acetonitrile (v/v, 40:60) as the mobile phase. Quantification was performed using a matrix-matched calibration curve, which was linear in the range of the 0.05-100 µg/L. The limit of detection (LOD) was estimated at 0.03 µg/kg for CQ on the basis of a peak to peak signal noise (S/N = 3). The limit of quantification (LOQ) was 0.1 µg/kg on the basis of the lowest spiked concentration with suitable precision and accuracy. The average recovery of CQ in spiked meat samples was 86.4-94.7% at 2, 20, and 200 µg/kg. Finally, this method was applied to determine CQ in the livestock and poultry meats purchased from markets in Beijing in 2011. CQ was detected in all 12 samples, and the concentration was 0.4-636.0 µg/kg. Concentrations in a chicken sample (636.0 µg/kg) and a goat meat sample (486.0 µg/kg) were found to be 15.9 and 2.43 times the corresponding Codex maximum residue limits, respectively.
Subject(s)
Chlormequat/analysis , Chlormequat/isolation & purification , Chromatography, High Pressure Liquid/methods , Meat/analysis , Plant Growth Regulators/analysis , Plant Growth Regulators/isolation & purification , Solid Phase Extraction/methods , Tandem Mass Spectrometry/methods , Animals , Cattle , Chickens , China , Food Contamination/analysis , Goats , Spectrometry, Mass, Electrospray Ionization/methods , SwineABSTRACT
A liquid chromatography-mass spectrometry (LC-MS) method for the identification and quantification of chlormequat (CQ) and mepiquat (MQ) in source waters with high sensitivity and specificity was established using WCX cartridges (150 mg/6 mL) for pre-concentration of the samples and using the CAPCELL PAK CR 1:4 (2.0 mm×150 mm 5 µm, SCX:C18=1:4) column containing strong cationic exchange resins and C18 for separation. The method could solve the problem for pre-concentrating ionic compounds from water samples and avoid the MS instrument fouling problem accompanied with the use of ion-pair reagents. After the optimization of analytical conditions, quantification was achieved in the positive electrospray ionization mode using selected ion monitoring. The samples were analyzed with multi-channel mode with quantification performed at 30 V cone voltage to ascertain the sensitivity and qualitative analysis performed at 60 V cone voltage simultaneously. The method detection limits (MDLs) of CQ and MQ in source water were determined to be 14 and 22 ng L(-1). Finally, the method was used to quantify CQ and MQ in several source waters, which gave a level ranging from below the quantitation limit to 28 ng L(-1).
