高等学校化学学报

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基于碳量子点过氧化物模拟酶的肌氨酸比色测定

舒馨,王迪,袁春玲,覃秀,王益林   

  1. 广西大学化学化工学院
  • 收稿日期:2020-09-28 修回日期:2020-10-26 出版日期:2020-11-14 发布日期:2020-11-14
  • 通讯作者: 王益林

Colorimetric Determination of Sarcosine with Carbon Quantum Dots as Mimetic Peroxidase

  • Received:2020-09-28 Revised:2020-10-26 Online:2020-11-14 Published:2020-11-14

摘要: 以果皮为原料制备水溶性碳量子点(CQDs),透射电镜分析表明其平均粒径为2.4 nm;红外光谱分析揭示CQDs表面富含含氧官能团。所得CQDs可催化H2O2氧化3,3',5,5'-四甲基联苯胺(TMB)生成蓝色氧化产物(ox-TMB)。基于上述反应,建立了测定H2O2的分析方法,在pH 3.5,温度40℃,TMB浓度1.0mmol/L及孵育时间15min的条件下,当H2O2浓度在5.0~100 μmol/L范围时,ox-TMB的吸光度随H2O2浓度的升高而线性增强,方法检出限为3.0 μmol/L。鉴于H2O2是肌氨酸氧化酶催化肌氨酸氧化的产物之一,建立了CQDs催化H2O2氧化TMB间接测定肌氨酸的分析方法。当肌氨酸浓度在0.5~350 μmol/L范围内时,吸光度与其浓度呈良好的线性关系,方法检出限为0.3 μmol/L,应用于人体尿样的测定,回收率在96%~99%范围内。

Abstract: Water soluble carbon quantum dots (CQDs) were prepared from peel. Transmission electron microscopy (TEM) analysis showed that the average particle size of CQDs was 2.4 nm. FTIR spectroscopy revealed that the surface of CQDs was rich in oxygen-containing functional groups. The obtained CQDs can catalyze the H2O2-mediated oxidation of 3,3',5,5'- tetramethylbenzidine (TMB) to produce corresponding blue oxidation product (ox-TMB). Thus, a simple method for the detection of H2O2 was established. Under the conditions of pH 3.5, temperature 40°C, TMB 1.0mmol/L and incubation time 15 min, the absorbance of ox-TMB increased linearly with increasing H2O2 concentration in the range of 5.0~100 μmol/L, the detection limit for H2O2 was 3.0 μmol/L. Given that H2O2 was one of the products of sarcosine oxidase (SOX)-catalyzed sarcosine oxidation, a method for the indirect detection of sarcosine based on CQDs-catalyzed and H2O2-mediated TMB oxidation was also developed. The increase of ox-TMB absorbance enabled the sensitive determination of sarcosine in the range of 0.5~350 μmol/L, and the detection limit (3σ/k) for sarcosine was calculated to be 0.3 μmol/L. The method exhibited its potential application in the detection of sarcosine in human urine samples with the recovery of 96 %~99 %.

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