Page 80 - Application Notebook - Solution for Food Safety

Liquid Chromatography Mass Spectrometry

Sensitive method for the determination of Fipronil and its
metabolite Fipronil Sulfone in egg using QuEChERS
sample pretreatment and LC-MS/MS detection
No. SCA_210_041 [LCMS-8060]

 Introduction of water and spiked with a respective amount of
Fipronil, Fipronil sulfone and in addition Fipronil-
Fipronil concerns a broad-spectrum insecticide desulfinyl and Fipronil-sulfide (neochema,
from the group of phenylpyrazoles used in many Germany).
countries as a biocide and plant protection product 10 mL of acetonitrile was added and the samples
against fleas, lice, ticks, cockroaches, mites and were mixed vigorously. After that ready to use
other insects. Fipronil is an active compound in QuEChERS extraction salts (Q-sep TM Q110,
veterinary products fighting tick and flea Pouch and tubes – cat. #26235, Restek) were
infestations in dogs and cats. The use as plant added for sample drying and buffering. Samples
protection product is restricted to seed treatment in were mixed again and centrifuged at 4500 rpm for
the European Union since 2007. However, due to 5 minutes. 1 mL of the supernatant was transferred
the illegal use as addition to the cleaning supplies into a dSPE tube (Q-sep TM QuEChERS dSPE –
used in chicken coops the eggs and meat might cat. #26217, Restek), shaken for 2 minutes,
get contaminated as well. centrifuged, the supernatant was transferred into a
The MRL (maximum residue levels) for Fipronil glass vial and the pH was adjusted with 5% formic
and and its metabolite Fipronil sulfone (which is acid solution in acetonitrile (10 µL/mL super-
classified as having similar toxicity) in eggs is set natant).
to 0.005 mg/kg by the EU (by definition the sum of
fipronil and fipronil-sulfone expressed as fipronil)  Materials and methods
[1], so that there is an actual requirement for the
determination of both compounds in egg matrix at
a relatively low level. Extracts were analyzed using a method set up
This application news presents a simple method with Shimadzu’s LC/MS/MS Method Package for
using a standard QuEChERS extraction protocol Residual Pesticides Version 2 and a Nexera X2
followed by LC-MS/MS detection. UHPLC system coupled to a LCMS-8060 mass
spectrometer. Analysis was carried out using MRM
Fipronil (Multi Reaction Monitoring) mode.
MF C H Cl F N OS
2 6
4
12
4
MW 437,1 g/mol

 Sample preparation

Compound extraction was performed using a
simple QuEChERS (Quick, Easy, Cheap, Effective,
Rugged and Safe) method.
5 g of egg (egg white and egg yolk) were weighted
into a 50 mL polypropylene tube, diluted with 5 mL