Development and validation of a highly-sensitive, quantitative LC-MS/MS assay to evaluate plasma oxytocin

Area of Science:

• Neuroscience
• Analytical Chemistry

Background:

• Oxytocin, a neuropeptide, regulates social behavior and is crucial for positive social interactions.
• Current immunoassay methods for measuring oxytocin in plasma have significant limitations, potentially leading to inaccurate results.
• Endogenous oxytocin levels in human plasma are exceptionally low, necessitating highly sensitive quantification techniques.

Purpose of the Study:

• To develop and validate a novel, highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for accurate oxytocin quantification in human plasma.
• To address the limitations of existing immunoassays for measuring low endogenous oxytocin concentrations.

Main Methods:

• Oxytocin was extracted using solid-phase extraction and analyzed via LC-MS/MS.
• Phosphate-buffered saline with bovine serum albumin (PBS-0.1% BSA) was used as a surrogate matrix to prevent endogenous interference.
• Method validation followed Clinical Laboratory Standards Institute guidelines, assessing precision, accuracy, and measurement uncertainty.

Main Results:

• Achieved a lower limit of quantification of 1 ng/L for oxytocin.
• Validated the method for concentrations from 1 ng/L to 75 ng/L.
• Demonstrated high precision (CV <10%), accuracy (94-108%), and measurement uncertainty (<15%).

Conclusions:

• A highly sensitive and validated LC-MS/MS method for plasma oxytocin quantification has been successfully developed.
• This novel methodology offers improved accuracy and reliability for clinical applications involving oxytocin measurement.