An accurate and robust LC-MS/MS method for the quantification of chlorfenvinphos, ethion and linuron in liver samples

authors

• Kadar Ali
• Peyre Ludovic
• de Sousa Georges
• Wortham Henri
• Doumenq Pierre
• Rahmani Roger

keywords

• 30
• Pesticide mixtures
• Liver samples
• LC-MS/MS
• Method validation
• 31
• 32
• Method validation
• Liver function tests
• Liver samples

document type

abstract

A method for the determination of chlorfenvinphos, ethion and linuron in liver samples by LC-MS/MS isdescribed. Sample treatment was performed by using Sola™polymeric reverse phase SPE cartridges after protein precipitation. Gradient elution using 10 mM ammonium formate in methanol (A) and 10 mM ammonium formate in water (B) was used for chromatographic separation of analytes on a Hypersil™ end-capped Gold PFP reverse phase column (100 mm _ 2.1 mm, 3 mm). All analytes were quantified without interference, in positive ionization mode using multiple reaction monitoring (MRM) with chlorfenvinphos-d10 as internal standard. The whole procedure was validated according to the FDA guidelines for bioanalytical methods. The calibration curves for chlorfenvinphos, linuron and ethion compounds were linear over the concentration range of 0.005e2 mM (i.e. 0.0018e0.720 mg/mL, 0.0019 e0.770 mg/mL and 0.0012e0.500 mg/mL respectively) with coefficients of determination higher than 0.998. A Lower limit of quantification of 0.005 mM was achieved for all analytes, i.e. 5.76, 6.08 and 3.84 mg/kg of liver for chlorfenvinphos, ethion and linuron respectively. Compounds extraction recovery rates ranged from 92.9 to 99.5% with a RSD of 2.3%. Intra- and inter-day accuracies were within 90.9 and 100%, and imprecision varied from 0.8 to 8.2%. Stability tests proved all analytes were stable in liver extracts during instrumental analysis (þ12 _C in autosampler tray for 72 h) at the end of three successive freeze-thaw cycles and at _20 _C for up to 9 months. This accurate and robust analytical method is therefore suitable for contamination or metabolism studies.

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