Identifying the D-Pentoses Using Water Adduction to Lithium Cationized Molecule

Area of Science:

• Analytical Chemistry
• Carbohydrate Chemistry
• Mass Spectrometry

Background:

• D-pentoses are simple sugars with various isomers that are challenging to differentiate.
• Accurate identification of pentose isomers is crucial in fields like metabolomics and glycobiology.
• Existing methods often require derivatization, adding complexity and potential for error.

Purpose of the Study:

• To develop a novel, direct method for distinguishing underivatized D-pentoses.
• To leverage mass spectrometry for isomer-specific analysis.
• To establish a rapid and accurate analytical technique for pentose discrimination.

Main Methods:

• Utilizing electrospray ionization (ESI) with a lithium salt to form lithiated pentose ions ([Pentose + Li]+).
• Employing a quadrupole ion trap to study the gas-phase reaction of lithiated pentoses with water.
• Analyzing unique water adduction reaction rates and the fraction of unreactive lithiated ions for each pentose isomer.

Main Results:

• Each D-pentose isomer exhibited a unique water adduction reaction rate.
• Multiple lithiation sites were observed, leading to a mixture of reactive and unreactive ions for each pentose.
• Complete discrimination of all D-pentose isomers was achieved by combining adduction rate and unreactive ion fraction data.

Conclusions:

• The developed mass spectrometry method effectively distinguishes underivatized D-pentoses.
• The unique gas-phase ion-molecule reactions provide a powerful tool for isomer resolution.
• This approach offers a simplified and highly specific analytical solution for pentose analysis.