双波长补偿光度法的研究及对微量铁的测定

A Study on the Dual-wavelength Compensation Spectrophotometry and Its Application to Micro Ferrum Determination

提出了新的双波长法并应用于茜素S（ARS）光度法测定铁。该法能消除显色剂ARS褪色对生成物Fe[ARS]，生色的相消干扰，测得生色法真实吸光度，消除生成物生色对有色剂ARS褪色的相消干扰，测得褪色法真实吸光度，以其生色吸光度与褪色吸光度绝对值之和作为信号，按信号吸光度法测定。于波长λN=423nm，λP=555nm测得信号吸光度补偿系数fn为2．227，测得摩尔吸光系数为2．154×10^4L·mol^-1·cm^-1，为经典法的2．135倍，线性范围为0—2mg／L，反应摩尔比为1：3。应用该法测定了某些样品中的铁。结果表明，该法用于存在相消干扰的光度分析及反应摩尔比测定等研究的效果优于经典光度法。

A novel dual-wavelength compensation spectrophotometry was established and applied to the determination of micro ferrum with alzarin red S（ARS） as the chromogenic reagent. This method could determine the real absorbance of the chromogenic product in spectrophotometry through eliminating the destructive interference of discolored ARS on the resultant chromogenic product, Fe [ARS] 3- It could also determine the real absorbanee of the discolored product in spectrophotometry through eliminating the destructive interference of Fe [ ARS ] 3 on the discolored ARS. The sum of the absolute chromogenic absorbance and discolored absorbance was taken as the signal determined by the spectrophotometry. The compensation coefficient fn of absorbance signal was 2. 227 at wavelength of 423 nm （λN） and 555 nm （λp） and the molar absorptivity was 2. 154 ×10^4 L· mol^-1 · cm^-1, which was 2. 135 times greater than that obtained by traditional method. The linear range was 0 -2 mg · L^-1. The proposed method was compared with the traditional method in terms of linear range and molar absorptivity. The results showed that the proposed method is superior to the traditional method. The method was also applied to the determination of ferrum in hair with satisfactory results.