journal6 ›› 2008, Vol. 29 ›› Issue (2): 96-100.

• Chemistry and chemical engineering • Previous Articles     Next Articles

Surface-Modification of CdS Nano-Particles by Using Pepsin and Its Analytical Application


  1. (1.College of Chemistry and Chemical Engineering,Jishou University,Jishou 416000,Hunan China;2.State Key Laboratory of Chemo/Biosensing and Chemometrics,Hunan University,Changsha 410082,China;3.Hunan Province Key Laboratory of Forest Product Chemical Industry Engineering,Jishou University,Zhangjiajie 427000,Hunan China)
  • Online:2008-03-25 Published:2012-05-25

Abstract: CdS semiconductor nano-particles were synthesized in aqueous solution by using mercaptoethylic acid as the stabilizer as well as surface-modification reagent.The average size of CdS nano-particles estimated from TEM graph is ca.10 nm.The CdS nano-particles exhibited strong ultraviolet absorption at 292 nm and fluorescence emission at 524.8 nm.When surface-modification of CdS nano-particles were replaced with pepsin,ultraviolet absorption peak kept same,fluorescence emission intensity decreased as well as fluorescence peak shifted to 462.4nm.Temperature and pH value influenced surface-modification of CdS nano-particles.Under optimal conditions,a concentration of 2~20 mg/L of pepsin could be determined on the basis of fluorescence intensity decrease ratio of CdS nano-particles,with a detection limit 3σ of 0.13 mg/L (n=10).The proposed method was applied to the detection of the concentration of pepsin in human gastric juice.

Key words: CdS nano-particles, pepsin, surface-modification, fluorescence determination

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