Use of a liquid chromatography-tandem mass spectrometry method to assess the concentration of epinephrine, norepinephrine, and phenylephrine stored in plastic syringes

Abstract Objectives There are concerns about the potency of epinephrine (EPI), norepinephrine (NE), and phenylephrine (PE) stored in syringes for later infusions in clinical care. The objective of our study was to optimize a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine the concentrations EPI, NE, and PE dissolved in normal saline and stored in 50 mL 3-part Becton Dickinson syringes. Methods Medications were diluted in normal saline to 80 μg/mL for EPI and NE, and 100 μg/mL for PE. The solutions were stored in syringes for 0 (fresh), 3, and 7 days in a medical refrigerator. United States Pharmacopeia grade EPI, NE, and PE and their deuterium-labeled analogs were used as calibration standards. Stored samples and standards were diluted and analyzed by LC-MS/MS operated in selected reaction monitoring mode. Results The calculated limit of quantification for EPI, NE and PE were well below the concentrations used in clinical practice. The coefficient of variation remained below 12 % for all samples. The standard linear calibration regressions for EPI, NE, and PE had r 2 values of between 0.96 and 0.98 (p < 0.001). EPI and NE stored in the refrigerator remained within 10 % of the of their initial concentrations at all time points. The concentration of PE in syringe decreased by 19.85 % at 3 days, with no further decrease at 7 days, compared to fresh PE. Conclusions The sample preparation steps and optimized LC-MS/MS method allowed simple and reliable measurements of EPI, NE, and PE.