Solid-state extraction of cortisol from plasma or serum for liquid chromatography

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Traditional liquid-liquid extraction for cortisol determination is labor-intensive and can lead to High-Performance Liquid Chromatography (HPLC) column contamination.
• Accurate and efficient cortisol measurement is crucial for diagnosing various endocrine disorders.

Purpose of the Study:

• To evaluate the efficacy of solid-state extraction as a sample preparation technique for cortisol analysis using HPLC.
• To compare the performance of solid-state extraction with traditional liquid-liquid methods and radioimmunoassay.

Main Methods:

• Solid-state extraction of cortisol from plasma and serum samples.
• Sample pretreatment with methanol to enhance extract yield.
• Analysis of extracted cortisol using High-Performance Liquid Chromatography (HPLC).
• Comparison of results with a commercial radioimmunoassay (RIA) procedure.

Main Results:

• Solid-state extraction significantly simplifies sample preparation for cortisol determination.
• HPLC column contamination was minimized using the solid-state extraction method.
• Methanol pretreatment enhanced the extract yield from solid-state columns.
• Cortisol values obtained via solid-state extraction/HPLC showed a strong correlation (r = 0.92) with radioimmunoassay results.

Conclusions:

• Solid-state extraction is a superior method for preparing plasma and serum samples for cortisol analysis by HPLC.
• This technique offers improved efficiency and reduced column maintenance compared to liquid-liquid extraction.
• The high correlation with RIA validates solid-state extraction/HPLC as a reliable method for cortisol quantification.