Spectrofluorimetric estimation of norepinephrine using ethylenediamine condensation method

Area of Science:

• Analytical Chemistry
• Biochemistry
• Pharmacology

Background:

• Norepinephrine (NE) is a crucial neurotransmitter and hormone.
• Accurate quantification of NE is vital for diagnosing and monitoring various physiological and pathological conditions.
• Existing methods for NE determination may lack sensitivity, simplicity, or be prone to interference.

Purpose of the Study:

• To develop a simple and highly sensitive method for norepinephrine determination.
• To validate the method's performance using biological samples and pharmaceutical preparations.
• To investigate and mitigate potential interferences, particularly from dopamine (DA).

Main Methods:

• Oxidation of norepinephrine (NE) using mercury (II) nitrate.
• Condensation of the oxidation product with ethylenediamine (EDA) to form a fluorescent compound.
• Enhancement of fluorescence intensity using acetone and measurement at specific wavelengths (excitation: 420 nm, emission: 507 nm).
• Application of first derivative synchronous fluorimetry with peak-to-zero technique to eliminate dopamine interference.

Main Results:

• A linear relationship between fluorescence intensity and NE concentration was observed in the range of 0.01 µM–0.014 mM.
• The method demonstrated a high correlation coefficient (0.99813) and a low detection limit (2.5 nM).
• Recovery efficiency in urine samples ranged from 95% to 98.62%, indicating good accuracy.
• Successful application of the method for determining NE in injection solutions.

Conclusions:

• The proposed method offers a simple, sensitive, and reliable approach for norepinephrine quantification.
• The method is effective in biological matrices like urine and in pharmaceutical formulations.
• The developed fluorimetric technique effectively overcomes interference from dopamine.