Liquid chromatography with tandem mass spectrometry for the determination of flufenoxuron in blood using automatic solid phase extraction and its application to a fatal case of flufenoxuron poisoning.
A liquid chromatography/tandem mass spectrometry method with solid phase extraction for the detection and the quantitation of flufenoxuron in an aliquot of blood was developed and validated. Flufenoxuron belongs to a benzoylurea insecticide and is the active ingredient of Cascade™. The analyte in postmortem specimens was extracted by solid-phase extraction with Bond Elut Certify cartridge. After the elution layer was evaporated, the residue was reconstituted with 70% methanol for LC/MS/MS analysis. Separations were carried out on a Synergi(®) 2.5u Fusion-RP 100 A column with column temperature kept at 40 °C at a flow rate of 0.4 mL/min. The mobile phase was composed of 5mM ammonium formate in 10% methanol and 5 mM ammonium formate in 90% methanol using gradient elution. A triple quadruple mass spectrometer equipped with an electrospray ionization source operated in a positive ion mode with selective reaction monitoring mode. Atrazine-d5 was used as internal standard. The assay was linear over 0.02-1.0 mg/L (r(2)=0.999). Limit of detection (LOD) and limit of quantitation (LOQ) in blood were 0.009 mg/L (S/N=3) and 0.02 mg/L (S/N=10), respectively. The accuracy and the precision were <14.9% of bias% and <8.1% of CV%, which are acceptable criteria according to toxicology laboratory guidelines. Relative recoveries with 0.02, 0.1 and 1.0mg/L (in blood) were 112.3%, 101.2% and 111.0% (n=5), respectively. The developed method was applied in forensic toxicology to determine flufenoxuron in postmortem specimens in a fatal case of flufenoxuron intoxication in a 48-year-old-man who was found dead on bed in a small room after vomiting on the floor. The postmortem heart blood, peripheral blood and gastric contents were analyzed for flufenoxuron with the result of 6.3 mg/L in heart blood, 3.2 mg/L in peripheral blood and 30.6 mg/kg in gastric contents, respectively. The concentration ratio of the heart/peripheral blood of flufenoxuron was 2.0, and the ratio of gastric contents/peripheral blood was 9.4, suggesting possible postmortem redistribution and there may be a massive amount of flufenoxuron orally ingested. This case study is the first report of lethal concentrations of flufenoxuron in postmortem specimens.
Drug & Forensic Toxicology Division, National Forensic Service, Gangwon-do 26460, Republic of Korea. Electronic address: rheejs@korea.kr.
Jongsook
J
Rhee
Drug & Forensic Toxicology Division, National Forensic Service, Gangwon-do 26460, Republic of Korea.
Byungsuk
B
Cho
Seoul Institute, National Forensic Service, Seoul 08036, Republic of Korea.
Juseon
J
Lee
Seoul Institute, National Forensic Service, Seoul 08036, Republic of Korea.
Sungmin
S
Moon
Seoul Institute, National Forensic Service, Seoul 08036, Republic of Korea.
Hyesun
H
Yum
D002853:Chromatography, Liquid; D053593:Forensic Toxicology / Q000379:methods; D005766:Gastrointestinal Contents / Q000737:chemistry; D006801:Humans; D007306:Insecticides / Q000097:blood* / Q000506:poisoning*; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D010671:Phenylurea Compounds / Q000097:blood* / Q000506:poisoning*; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry
D007306:Insecticides; D010671:Phenylurea Compounds; C067660:flufenoxuron
Blood; Fatal; Flufenoxuron; LC/MS/MS; Postmortem