Used to measure norepinephrine (NE) levels in biological samples such as serum, plasma, cerebrospinal fluid, and tissue homogenates. Commonly applied in neuroscience research to study stress responses, neurotransmitter regulation, and autonomic nervous system function. Helps in evaluating neuroendocrine changes in animal models of depression, anxiety, cardiovascular diseases, and neurodegenerative disorders. Provides a sensitive and specific means to quantify NE without the need for radioisotopes, enabling safer and high-throughput analysis in laboratory settings.