A highly sensitive caffeine immunoassay based on a monoclonal antibody

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biochemistry

Background:

• Caffeine is a common contaminant in surface waters.
• Accurate quantification of caffeine is essential for environmental and consumer safety.
• Existing analytical methods can be time-consuming and expensive.

Purpose of the Study:

• To develop a new, sensitive immunoassay for caffeine quantification.
• To validate the assay's performance in various matrices, including environmental samples and consumer products.
• To compare the assay results with a standard analytical technique.

Main Methods:

• Development of a new immunoassay utilizing a monoclonal antibody against caffeine.
• Synthesis of a novel tracer with horseradish peroxidase for UV-visible detection.
• Application of solid-phase extraction (SPE) to enhance detection limits.
• Validation using liquid chromatography-tandem mass spectrometry (LC-MS-MS).

Main Results:

• The immunoassay achieved a limit of quantitation of 0.025 microg L(-1) for direct analysis.
• The limit of detection was 0.001 microg L(-1), further improved by SPE.
• The assay successfully quantified caffeine in beverages, shampoo, and tablets.
• ELISA results showed good correlation with LC-MS-MS across different matrices.
• Caffeine was detected in all tested surface waters from Berlin above 0.030 microg L(-1).
• High-throughput analysis of 66 samples was possible within 2 hours.

Conclusions:

• The developed immunoassay provides a reliable and efficient method for caffeine detection.
• The assay is versatile, applicable to environmental samples and various consumer products.
• This method offers a valuable tool for environmental monitoring and quality control of caffeine-containing products.