UPLC-MS/MS Method for Detection of Etomidate and Its Metabolite Etomidate Acid Quantity in Blood

To establish a method for the simultaneous quantitative analysis of etomidate and its metabolite etomidate acid in blood, and to discuss its application value in actual cases.

Acetonitrile precipitate protein method was used, and C₁₈ column was selected. Gradient elution was performed with acetonitrile and 5 mmol/L ammonium acetate within 6 min. Electrospray ionization source in positive ion mode was used. The internal standard etomidate acid-d₅ was obtained by etomidate-d₅ alkaline hydrolysis reaction. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used for quantitative analysis. The methodological verification was conducted.

Etomidate and etomidate acid in blood showed good linear relationship in the quantitative linear range (r>0.999), with the lower limit of quantification was 2.5 ng/mL and 7.5 ng/mL, respectively. The accuracy, precision, recovery rate, and matrix effect of the method met the professional verification standards. The practical application results showed that etomidate and etomidate acid could be detected in the blood of the abusers, and their mass concentrations ranged from 17.24 to 379.93 ng/mL.

The method established in this study can simultaneously quantify etomidate and etomidate acid in blood, which is simple and convenient to operate with accuracy. It can meet the detection needs of actual cases and provide technical support for law enforcement to crack down on etomidate abuse.