Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography-tandem mass spectrometry

A sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid-liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC-MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC-MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005-0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.

Ion chromatography tandem mass spectrometry for simultaneous confirmation and determination of indandione rodenticides in serum

This paper describes a simple method for the simultaneous determination and confirmation of the indandione rodenticides in serum. After samples were extracted with 10% (v/v) methanol in acetonitrile and cleaned by solid-phase extraction, chromatographic separation was performed on an IonPac AS11 analytical column (250 x 4.0 mm) using gradient KOH eluent with 10% (v/v) methanol as organic modifier. Confirmation was depended on the extensive fragmentation of the indandione molecule under MS/MS conditions which provides sufficient structural information. Quantification was performed by negative electrospray ionization in multiple reaction monitoring mode. All the method parameters were validated. It was confirmed that this method could be used in clinical diagnosis and forensic toxicology.

Development of a cell culture/ELISA assay to detect anticoagulant rodenticides and its application to analysis of rodenticide treated grain

This study describes a generic biological screening assay designed to detect anticoagulant rodenticides based on their inhibitory action on the vitamin K epoxide reductase protein complex, resulting in an accumulation of under-carboxylated prothrombin or proteins induced by vitamin K antagonism (PIVKA-II). A combined cell culture/ELISA assay was optimized to measure PIVKA-II production by the human hepatoma HepG2 cell line cultured in the presence of anticoagulant rodenticides. The specificity and sensitivity of the assay was validated using 41 grain extracts containing representative concentrations of rodenticide or appropriate nonrodenticide control compounds. In all cases, PIVKA-II produced by HepG2 cells in response to grain extracts spiked with rodenticides was detected by ELISA, while PIVKA-II was not detected in supernatants collected from cells exposed to nonrodenticide controls. This represents a novel, class-specific biological assay for the detection of anticoagulant rodenticides present in contaminated grain.

Determination of chlorophacinone and diphacinone in commercial rodenticides by liquid chromatography-UV detection and liquid chromatography-electrospray ionization mass spectrometry

This work describes a simple method for the determination and mass-spectrometric confirmation of the indanediones in commercial rodenticides. The sample is sonicated in methanol containing 2% formic acid and analyzed by liquid chromatography-UV detection. Once retention time and UV-Vis spectrum provide tentative identification, mass-spectrometric confirmation is obtained by analyzing a second aliquot by LC and electrospray ionization mass spectrometry (LC-ESI-MS). The extensive fragmentation of the indanedione molecule under MS/MS conditions provides sufficient structural information for positive identification on analyte levels as low as 20 ng on column.