New method for caffeine quantification by planar chromatography coupled with electropray ionization mass spectrometry...

Area of Science:

• Analytical Chemistry
• Chromatography
• Mass Spectrometry

Background:

• Quantification of caffeine in pharmaceuticals and energy drinks is crucial for quality control.
• Existing methods like HPTLC/UV may have limitations in sensitivity and precision.
• Stable isotope dilution analysis (SIDA) offers potential for improved accuracy in quantitative mass spectrometry.

Purpose of the Study:

• To develop and validate a novel high-performance thin-layer chromatography/electrospray ionization mass spectrometry (HPTLC/ESI-MS) method for caffeine quantification.
• To utilize stable isotope dilution analysis (SIDA) for enhanced accuracy and precision.
• To compare the performance of the developed method with a validated HPTLC/UV method.

Main Methods:

• Development of an HPTLC/ESI-MS method coupled with SIDA for caffeine quantification.
• Use of caffeine-d3 as an internal standard for correcting positioning errors.
• Densitometric detection by UV absorption and quantification by mass spectrometry (MS) in single ion monitoring (SIM) mode.
• Validation of the method by assessing linearity, repeatability, intermediate precision, and accuracy against HPTLC/UV.

Main Results:

• The HPTLC/SIDA-ESI-MS method demonstrated excellent linearity (R²=0.9998).
• High repeatability (
• The developed method showed no significant difference in accuracy compared to the HPTLC/UV method.
• Detection and quantification limits were significantly lower (factor of 13) than HPTLC/UV.
• SIDA effectively nullified positioning errors, enhancing reliability.

Conclusions:

• HPTLC/SIDA-ESI-MS is a highly reliable and accurate method for quantifying caffeine in complex matrices like pharmaceuticals and energy drinks.
• The method offers improved sensitivity and precision over traditional HPTLC/UV techniques.
• This approach provides a robust platform for online quantification in planar chromatography coupled with mass spectrometry.