Sensitive Oxidation of Sorbitol-Mediated Fe²⁺ by H₂O₂: A Reliable TD-NMR Method for Clinical Blood Glucose Detection

Abstract

The clinical challenge of high-accuracy blood glucose detection schemes is to overcome the detection error caused by the background interferences in different individuals. H 2 O 2 as the specific product of glucose oxidation can be involved in the Fe 2+ /Fe 3+ conversion and detected by the time-domain nuclear magnetic resonance (TD-NMR) method sensitively. But, in clinical applications, the oxidation of Fe 2+ is susceptible to the complex sample substrates. In this work, we sorted out two kinds of possible interference mechanisms of Fe 2+ oxidation in the NMR blood glucose detection method and proposed a feasible scheme that uses sorbitol to weaken the adverse effects of interference. We found that sorbitol-mediated Fe 2+ can greatly enhance the sensitivity of the T 2 value to H 2 O 2 . The chain reaction caused by sorbitol can significantly amplify the efficiency of Fe 2+ oxidation at the same concentration of H 2 O 2 . Thereby, we can achieve the higher dilution multiple of serum samples to reduce the amount of interfering substances involved in the Fe 2+ /Fe 3+ conversion. We justified the accuracy and availability of our method by successfully detecting and confirming the correlation between the T 2 decrease and glucose concentration of the serum samples collected from 16 subjects. The sorbitol−Fe 2+ glucose detection method with high sensitivity can be further combined with miniature NMR analyzers to satisfy the calibration requirements of glucose monitoring in diabetic patients instead of frequent medical visits.

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