An Efficient Solid Phase Extraction Method for Purification and Analysis of Compound-Specific Plant Sugar Stable...

Area of Science:

• Plant physiology
• Stable isotope geochemistry
• Analytical chemistry

Background:

• Stable hydrogen isotope composition (δ²H) in plants offers insights into environmental and metabolic processes.
• Interpreting δ²H values is challenging due to limited mechanistic understanding, especially for key compounds like sucrose.
• Current methods for preparing plant carbohydrates for isotopic analysis are time-consuming.

Purpose of the Study:

• To develop and evaluate an efficient method for analyzing the δ²H values of plant carbohydrates, specifically sucrose.
• To improve the time-efficiency of sample preparation for isotopic analysis of plant sugars.
• To enable better understanding of the factors influencing cellulose δ²H.

Main Methods:

• Acetylation of soluble carbohydrates from plant extracts (hot water or 80% ethanol).
• Purification of acetylated carbohydrates using liquid-liquid separation (LL) or solid-phase extraction (SPE).
• Analysis of acetylated sucrose and starch-derived glucose using gas chromatography-isotope ratio mass spectrometry (GC-IRMS).

Main Results:

• Acetylation allowed sufficient resolution of sucrose and glucose for GC-IRMS analysis.
• No significant isotopic bias was detected across the evaluated methods.
• The 80% ethanol extraction method yielded approximately threefold higher sucrose compared to water.
• The SPE purification method doubled sample throughput compared to the LL method.

Conclusions:

• An efficient method for compound-specific plant carbohydrate δ²H analysis via GC-IRMS has been established.
• This method facilitates investigations into the processes determining cellulose δ²H.
• It aids in distinguishing between metabolic and hydro-climatic sources of isotopic variation in plants.