Chem. J. Chinese Universities ›› 2021, Vol. 42 ›› Issue (6): 1761.doi: 10.7503/cjcu20200719

• Chemical Biology • Previous Articles     Next Articles

Colorimetric Determination of Sarcosine with Carbon Quantum Dots as Mimetic Peroxidase

SHU Xin, WANG Di, YUAN Chunling, QIN Xiu, WANG Yilin()   

  1. School of Chemistry and Chemical Engineering,Guangxi University,Nanning 530004,China
  • Received:2020-09-28 Online:2021-06-10 Published:2021-06-08
  • Contact: WANG Yilin E-mail:theanalyst@163.com
  • Supported by:
    the Natural Science Foundation of Guangxi Province, China(2018GXNSFAA050015)

Abstract:

Water soluble carbon quantum dots(CQDs) were prepared from fruit skin. Transmission electron microscopy(TEM) analysis showed that the average particle size of the CQDs was 2.4 nm. Fourier transform infrared spectroscopy(FTIR) revealed that the surface of CQDs was predominated in oxygen-containing functional groups. The obtained CQDs could catalyze the H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine(TMB) to produce the corresponding blue oxidized product(ox-TMB). Thus, a simple method for the detection of H2O2 was established. Under the conditions of pH=3.5, temperature of 40 °C, 1.0 mmol/L TMB and incubation time of 15 min, the absorbance of ox-TMB increased linearly with the increase of H2O2 concentration in the range of 5.0—100 μmol/L, and the detection limit(3σ/k) for H2O2 was 3.0 μmol/L. Given the fact 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 deve-loped. 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 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 94%—99%.

Key words: Carbon quantum dot, Mimetic enzyme, Colorimetry

CLC Number: 

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