电导滴定法测定氨基化磁性微球表面氨基含量  

QUANTITATIVE ANALYSIS OF THE CONTENT OF AMIDO GROUP ON THE SURFACE OF MAGNETIC BEADS WITH CONDUCTOMETRIC TITRATION

作　　者：李双[1] 陈风春[1] 曾荣华[1] 刘忠文[1] 刘芳[1] 刘飞[1] 杨丹凤[1] 周焕英[1] 

机构地区：[1]军事医学科学院卫生学环境医学研究所,天津300050

出　　处：《解放军预防医学杂志》2015年第2期124-126,共3页Journal of Preventive Medicine of Chinese People's Liberation Army

摘　　要：目的建立电导滴定法测定磁性微球表面微量氨基的化学计量点选择新方法,定量分析其氨基含量,为其表面修饰及偶联奠定基础。方法观察不同因素对滴定结果准确度的影响,在此基础上采用电导滴定法对磁性微球表面氨基进行定量测定,比较曲线拟合及电导率的变化率(ΔK)确定化学计量点2种不同方法对滴定结果的影响。结果建立了更为直接、客观的电导滴定法测定磁性微球表面微量氨基的新方法。利用滴定曲线拟合计算氨基化磁性微球表面氨基含量为(35.05±14.18)μmol/g(RSD=40.47%,n=5);而用ΔK确定化学计量点计算氨基化磁性微球表面氨基含量为(51.38±2.91)μmol/g(RSD=5.66%,n=5),后者的测定精度明显高于前者。结论利用电导率的变化率(ΔK)确定滴定拐点更为直接客观,降低了主观误差,测定精度较高。Objective To determine the content of amido groups on the surface of magnetic beads by conductometric titration,and to reduce the subjective chosen error of stoichiometric points in conductometric titra- tion, so as to provide the basis for further functional modification and biomolecular coupling of magnetic heads. nehods The influences of different factors on titration were observed. The selection of stoichiometric points of con- ductometric titration method based on the optimized condition was investigated. Then the advantage of the conduc- tivity change rate（AK） method was compared with direct curve fitting method reported before. Results A new ap- proach of conductometric titration was established to quantify the amido groups on the surface of magnetic beads, the content of amido groups on the surface of magnetic beads calculated by curve fitting and this method （ determined by AK）was （35.05±14.18） IxmoL/g, and （51.38±2.91） μmol/g respectively. Influences were distinct as stoi- chiometric points chosen in different ways. The RSD of this method （determined by AK） was 5.66% （n = 5 ） ver- sus 40.47% （n=5）of direct curve fitting one. Conclusion This method （AK） is more objective and precise which could reduce the subjective chosen error of stoichiometric points.

关 键 词：电导滴定 磁性微球 氨基 两点法 

分 类 号：O655.11[理学—分析化学]