Abstract: Objective To develop a high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） method for the determination of the content of 4-fluoromethamphetamine （4-FMA） in rat plasma, and to provide a methodological basis for the study of the toxicokinetics of 4-FMA in rats. Methods Rat plasma samples were added into internal standard methamphetamine （MA）. Its proteins were precipitated with methanol and then separated with Poroshell 120 EC-C18 chromatographic column. A 0.1% formic acid aqueous solution and a 0.1% formic acid acetonitrile solution were used as the mobile phase at the flow rate of 0.4 mL/min. Electrospray ionization source was used for detection in the multiple reaction monitoring （MRM） mode. Results The linear relationship was good when the mass concentration of 4-FMA in plasma samples was in the range of 5-1 000 ng/mL （r>0.999）. The limit of detection （LOD） was 3 ng/mL and the limit of quantification （LOQ） was 5 ng/mL. The accuracy was expressed as relative error （RE）, and in the range of ±5%, the intra-day precision and inter-day precision （relative standard deviation, RSD） less than 9%, and the extraction recovery rate was more than 90%. The analysis and detection of plasma samples were completed within 2.5 min. Conclusion This study developed a HPLC-MS/MS method for the determination of 4-FMA in rat plasma samples. This method is accurate, rapid, simple and sensitive and can be applied to the study of toxicokinetics of 4-FMA.

Key words: forensic toxicology, high performance liquid chromatography-tandem mass spectrometry, 4-fluoromethamphetamine, plasma, rats