分光光度法测定马铃薯淀粉中锌的研究

Determination of Zn^(2+) content in potato starch by spectrophotometry

研究了以十二烷基苯磺酸钠为表面活性剂,使显色剂1-(2-吡啶偶氮)-2-萘酚(PAN)与Zn2+产生显色反应,通过采用分光光度计测定吸光值以确定Zn2+含量。结果表明:当pH值为9.2时,最大吸收波长为595nm,表观摩尔系数为ε595nm=4.12×104L/(mol·cm),Zn2+浓度在0～30μg/50mL范围内符合比尔定律。该方法可以简单、快捷地用于马铃薯淀粉中微量锌的测定。

The method of determination the content of Zn^2＋ in potato starch suspension by spetrophotometry was explored in this paper. Lauryl benzene sulfonic acid sodium was used as surfactant and 1-（2-pyridylazo）- 2-naphthol （PAN） was applied as color reagent. Results show that when the pH value of the starch suspension is 9.2, apparent mole coefficient E505nm, is 4.12×10^4 L/（mol.cm）, the content of Zn^2＋ is lower than 30 μg/50 mL, the relationship between the absorbance under wavelength 595 nm and Zn^2＋ content follows Beer Law. Comparing with fluorescent method and other methods, this method is demonstrated to be more simple and efficient for analyzing trace zinc content in potato starch.