The interaction of bromothymol blue（BB） with human serum albumin（HSA） was studied by electrochemical techniques and a sensitive method for proteins assay was developed. When BB interacted with HSA, the voltammetri...The interaction of bromothymol blue（BB） with human serum albumin（HSA） was studied by electrochemical techniques and a sensitive method for proteins assay was developed. When BB interacted with HSA, the voltammetric peak current value of BB decreased linearly with the concentration of HSA in a range of 1.0--40.0 mg/L, and the peak potential shifted negatively. Based on the results, a sensitive assay method for proteins, such as HSA, bovine serum albumin（BSA）, and egg albumin etc. was established. This method was further applied to determining the HSA in healthy human blood samples, and the results are not significantly different from those obtained by the classic Coomassie Brilliant Blue G-250 spectrophotometic method. The detecting conditions of this method were optimized and the interaction mechanism was discussed. The results show that the electrochemical parameters（formal potential E^0, standard rate constant of the electrode reaction ks, parameter of kinetic nα） of BB have no obvious changes before and after the interaction, which indicate that BB can interact with HSA, forming an electrochemical non-active complex. The equilibrium constant（βs） and the binding ratio（m） for this complex were calculated. The m is 4 and βs is 1.41 × 10^19. This method is fast, simple, highly sensitive, and has good selectivity, which can be used in clinical measurements.展开更多
由于小檗碱氧化电位较高(>1.1 V vs. Ag/AgCl),进行生物样品中小檗碱的选择性电化学分析具有挑战性。基于溴百里酚蓝(BTB)和小檗碱的分子间非共价作用,通过单壁碳纳米管(SWNTs)将BTB修饰在电极表面并通过电化学聚合产生poly-BTB,利用...由于小檗碱氧化电位较高(>1.1 V vs. Ag/AgCl),进行生物样品中小檗碱的选择性电化学分析具有挑战性。基于溴百里酚蓝(BTB)和小檗碱的分子间非共价作用,通过单壁碳纳米管(SWNTs)将BTB修饰在电极表面并通过电化学聚合产生poly-BTB,利用聚BTB(poly-BTB)电极过程可逆以及氧化还原电位低的特点,以poly-BTB同时作为小檗碱的识别元件和电化学探针建立了小檗碱的电化学分析新方法。循环伏安和电化学阻抗谱结果表明,poly-BTB和小檗碱的分子间作用导致小檗碱结合在poly-BTB/SWNTs修饰电极表面,从而引起修饰电极的峰电流下降。在最优化的实验条件下,poly-BTB/SWNTs修饰电极的电流下降率和小檗碱的浓度在0.05~1μmol/L和1~100μmol/L范围内呈良好线性关系,检测限为0.022μmol/L。动物实验结果表明,该方法对生物样品具有很好的选择性,可用于血浆和肝脏匀浆中小檗碱含量的测量,为小檗碱相关的生理病理研究提供了一种简单有效的方法。展开更多
Two chemical methods which are commonly used for rice grain freshness determination were investigated for their efficiencies. Method 1 is made of bromothymol blue indicator, and the principle is based on indicator＇s ...Two chemical methods which are commonly used for rice grain freshness determination were investigated for their efficiencies. Method 1 is made of bromothymol blue indicator, and the principle is based on indicator＇s color which is changed in according to pH of the stored rice grains. Method 2 is based on peroxidase activity which deteriorates during storage of rice grains. Both methods were used for determination of fresh-aged rice index of six Thai-rice cultivars, four from non-waxy rice cultivars （KDML 105, Chai Nat 1, Chai Nat 2 and Phitsanulok 2） and two from waxy rice cultivars （San-pah-tawng and RD6）. Rice samples were kept in the forms of paddy and polished rice. Fresh-aged rice indices were determined using both methods every two weeks over the storage period of 24 weeks （six months）. It was found that both methods were capable of detecting fresh-aged rice indices. The color of chemical solutions changed with regards to the age of rice grains and it could be detected spectrophotometrically. Rice grains which have been kept as paddy provided more consistent results. Method 1 is recommended for industrial application as it is simple, efficient and inexpensive.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.20635020 and 20375020)Doctorial Foundation of the Ministry of Education of China(No.20060426001)
文摘The interaction of bromothymol blue（BB） with human serum albumin（HSA） was studied by electrochemical techniques and a sensitive method for proteins assay was developed. When BB interacted with HSA, the voltammetric peak current value of BB decreased linearly with the concentration of HSA in a range of 1.0--40.0 mg/L, and the peak potential shifted negatively. Based on the results, a sensitive assay method for proteins, such as HSA, bovine serum albumin（BSA）, and egg albumin etc. was established. This method was further applied to determining the HSA in healthy human blood samples, and the results are not significantly different from those obtained by the classic Coomassie Brilliant Blue G-250 spectrophotometic method. The detecting conditions of this method were optimized and the interaction mechanism was discussed. The results show that the electrochemical parameters（formal potential E^0, standard rate constant of the electrode reaction ks, parameter of kinetic nα） of BB have no obvious changes before and after the interaction, which indicate that BB can interact with HSA, forming an electrochemical non-active complex. The equilibrium constant（βs） and the binding ratio（m） for this complex were calculated. The m is 4 and βs is 1.41 × 10^19. This method is fast, simple, highly sensitive, and has good selectivity, which can be used in clinical measurements.
文摘由于小檗碱氧化电位较高(>1.1 V vs. Ag/AgCl),进行生物样品中小檗碱的选择性电化学分析具有挑战性。基于溴百里酚蓝(BTB)和小檗碱的分子间非共价作用,通过单壁碳纳米管(SWNTs)将BTB修饰在电极表面并通过电化学聚合产生poly-BTB,利用聚BTB(poly-BTB)电极过程可逆以及氧化还原电位低的特点,以poly-BTB同时作为小檗碱的识别元件和电化学探针建立了小檗碱的电化学分析新方法。循环伏安和电化学阻抗谱结果表明,poly-BTB和小檗碱的分子间作用导致小檗碱结合在poly-BTB/SWNTs修饰电极表面,从而引起修饰电极的峰电流下降。在最优化的实验条件下,poly-BTB/SWNTs修饰电极的电流下降率和小檗碱的浓度在0.05~1μmol/L和1~100μmol/L范围内呈良好线性关系,检测限为0.022μmol/L。动物实验结果表明,该方法对生物样品具有很好的选择性,可用于血浆和肝脏匀浆中小檗碱含量的测量,为小檗碱相关的生理病理研究提供了一种简单有效的方法。
基金financially supported by the Thailand Research Fund(TRF)(Grant No.MRG-WI535S078)
文摘Two chemical methods which are commonly used for rice grain freshness determination were investigated for their efficiencies. Method 1 is made of bromothymol blue indicator, and the principle is based on indicator＇s color which is changed in according to pH of the stored rice grains. Method 2 is based on peroxidase activity which deteriorates during storage of rice grains. Both methods were used for determination of fresh-aged rice index of six Thai-rice cultivars, four from non-waxy rice cultivars （KDML 105, Chai Nat 1, Chai Nat 2 and Phitsanulok 2） and two from waxy rice cultivars （San-pah-tawng and RD6）. Rice samples were kept in the forms of paddy and polished rice. Fresh-aged rice indices were determined using both methods every two weeks over the storage period of 24 weeks （six months）. It was found that both methods were capable of detecting fresh-aged rice indices. The color of chemical solutions changed with regards to the age of rice grains and it could be detected spectrophotometrically. Rice grains which have been kept as paddy provided more consistent results. Method 1 is recommended for industrial application as it is simple, efficient and inexpensive.
