摘要
采用0．1％EBT-20％NH3-NH4Cl-聚乙二醇体系及分光光度法测定钙，并选择2％聚乙二醇水溶液配制的铬黑T进行显色．试验结果表明：用聚乙二醇水溶液配制的铬黑T水溶液红移了28nm，Ca（Ⅱ）-EBT络合物最大吸收波长蓝移了68nm，且终点变色的对比度（At）增大了40nm，同时变色敏锐度提高，平行测定时颜色稳定，用于滴定分析时可减少误差，提高滴定分析的准确度．将该法用于测定钙离子，在510nm处m值约为0．65×10^4L／mol·cm，钙量在0～10μg／mL服从比耳定律，线性回归方程为A=0．0065C＋0．0708（其中A为吸光度，C为μg／25mL），相关系数r=0．99945．研究表明该法适于在水体和食品检测中应用．
In this paper, a 0. 1 % EBT-20 % NHg-NH4Cl-polyethylene glycol system to be used in spectrophotometric determination of calcium, choose 2 % aqueous solution of poly- ethylene glycol preparation of chromium black T-measured color. The results showed that： the preparation of polyethylene glycol solution of chromium black T made chrome black T-a- queous solution redshift 28 nm; Ca （Ⅱ ） - EBT complex maximum absorption wavelength blue-shift of 68 nm; end of the change in color of contrast （△λ） increased 40 nm; the acuity of the degree of discoloration raised; titration error reduction; titration analysis of the improved accuracy. Applied to the determination of calcium ions, in the 510 nrn, co value of a- bout 0.65× 10^4 L/mol· cm, calcium content in the 0 to 10 μ g / mL Beer＇s law is obeyed, linear regression equation is. A=0. 006 5 c ＋0. 070 8 （where A is absorbance, c for/2g/25 mL） correlation coefficient of r=0. 999 45, appling in the water and food testing.
出处
《陕西科技大学学报（自然科学版）》
2008年第4期58-60,68,共4页
Journal of Shaanxi University of Science & Technology
关键词
铬黑T
分光光度法
钙
显色剂
络合剂
chrome black T
spectrophotometry
calcium
reagent
complexone
