2-氨基-3-[(2-羟基-5-硝基-亚苄基)氨基]-2-丁烯二腈分光光度法测定茶叶中微量钴

Determination of Trace Co^(2+) in Tea by the Spectrophotometry of 2-amino-3-[(2-hydroxy-5-cotro-benzylidene)-amino]-but-2-enedinitrile

研究了2-氨基-3-[(2-羟基-5-硝基-亚苄基)氨基]-2-丁烯二腈与钴(Ⅱ)作用的吸收光谱,在pH为6.86的KH2PO4-Na2HPO4的缓冲体系中,钴与显色剂形成物质的量比为1∶2的橘色配合物,在248nm处有最大吸收峰,摩尔吸光系数ε=2.30×104 L.mol-1.cm-1,钴质量浓度在0.2～0.6μg/mL范围内与吸光度呈良好的线性关系(R=0.997 7),线性回归方程为Y=0.288 52 X-0.006,桑德尔灵敏度S=2.56×10-3μg/cm2。

2-amino-3-[（2-hydroxy-5-cotro-benzylidene）-amino]-but-2-enedinitrile was used as the analytical reagent for the determination of cobalat（Ⅱ）.The optimal conditions for complex formation of this Schiff Base with cobalat（Ⅱ） were obtained.An orange colored coordination complex was formed while the pH is 6.86,between the new color reagent and cobalat（Ⅱ） with a mole ratio（L：cobalat（Ⅱ）） of 2∶1,and its maximum absorption was found at the wavelength 248 nm.Y=0.288 52X-0.006,the calibration curve of cobalat（Ⅱ） with good linearity（R=0.997 7） were obtained over the range of 0.2—0.6 μg/mL.The apparent molar absorptivity was 2.30×104 L·mol-1·cm-1,and its Sandell sensitivity was found to be 2.56×10-3 μg/cm2.