Determination of Glucose in Submicroliter Samples by CE-LIF Using Precolumn or On-Column Enzymatic Reactions

Area of Science:

• Analytical Chemistry
• Biochemistry
• Biomedical Engineering

Background:

• Accurate glucose determination is crucial for diabetes management and research.
• Traditional methods often require larger sample volumes and complex procedures.
• Developing sensitive, rapid, and low-volume glucose assays is essential.

Purpose of the Study:

• To develop and validate a capillary electrophoresis (CE) method for glucose determination using enzymatic reactions and laser-induced fluorescence (LIF).
• To compare the performance of precolumn and on-column enzymatic reaction schemes for glucose analysis.
• To assess the feasibility of noninvasive glucose monitoring using tear fluid.

Main Methods:

• Enzymatic reactions involving glucose oxidase and peroxidase to generate a fluorescent signal proportional to glucose concentration.
• Capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection.
• Comparison of precolumn derivatization and on-column reaction strategies for sample analysis.

Main Results:

• Both precolumn and on-column methods achieved high sensitivity, with detection limits of 50 nM and 800 nM for precolumn and on-column, respectively.
• Methods demonstrated linearity over tested ranges (100 nM-30 μM for precolumn, 1-100 μM for on-column) with reproducibility <5% RSD.
• Successful analysis of glucose in human tear fluid (approx. 138 μM) using both methods, demonstrating potential for noninvasive monitoring.

Conclusions:

• The CE-LIF method with enzymatic reactions provides a sensitive and efficient approach for glucose determination in low-volume samples.
• The precolumn reaction strategy offers superior sample handling and detectability compared to the on-column approach.
• This technique holds promise for noninvasive glucose monitoring, particularly in applications involving tear fluid analysis.