Phenylalanine in whole blood and plasma--a candidate reference method

Area of Science:

• Biochemistry
• Analytical Chemistry
• Clinical Chemistry

Background:

• Accurate phenylalanine quantification is crucial for diagnosing and monitoring metabolic disorders.
• Existing methods may require complex extraction or sophisticated instrumentation.

Purpose of the Study:

• To develop and validate a straightforward method for phenylalanine quantification in whole blood and plasma.
• To utilize isotope dilution gas chromatography-mass spectrometry (GC-MS) with a novel derivative for enhanced simplicity.

Main Methods:

• Isotope dilution gas chromatography-mass spectrometry (GC-MS) was employed.
• A unique derivative facilitated a simplified extraction process.
• Quantification was performed using a basic mass spectrometer setup.

Main Results:

• The method demonstrated high precision with a within-batch relative standard deviation of 1.3% and a between-batch of 2.1%.
• A low detection limit of 7 pmol injected was achieved.
• The procedure's ruggedness and sample handling were assessed and found to be reliable.

Conclusions:

• The developed GC-MS method provides a simple, precise, and sensitive approach for phenylalanine quantification in biological samples.
• This method is suitable for routine clinical laboratory use, even with basic mass spectrometry equipment.