铁(Ⅲ)-邻菲罗啉间接光度法测定对乙酰氨基酚的含量

Determination of Acetaminophen in Cold Medicine by Indirect Spectrophotometry with Iron(Ⅲ)-phenanthroline System

pH值为2~9的Fe(Ⅲ)溶液中,加入对乙酰氨基酚,将Fe(Ⅲ)定量还原为Fe(Ⅱ),Fe(Ⅱ)离子与邻菲罗啉形成橘红色配合物(λmax=511 nm).结果表明,对乙酰氨基酚含量(ρ)4.00~48.00μg·mL-1范围内,配合物溶液吸光度与对乙酰氨基酚含量呈良好的线性关系,其线性回归方程为A=0.021ρ+0.052 8,线性相关系数r=0.999 7.方法用于感冒药中对乙酰氨基酚含量的测定,测定的相对标准偏差为0.3%~0.7%(n=10),加标回收率为95.6%~101.6%(n=10),方法检出限为0.71μg·mL-1,测定结果与药典法相近.

Iron(Ⅱ) and phenanthroline could found orange complex which has maximum absorption wavelength of 511 nm during pH value of 2~9.When acetaminophen was added into the iron(Ⅲ)-phenanthroline system,the iron(Ⅲ)) ions would be reduced to iron(Ⅱ) ions,and the orange complex’s absorbance(A) had good linear relationship with the contents of acetaminophen (ρ) from 4.00μg· m L-1 to 48.00μg· m L-1. The linear regression equation was A=0.021ρ+0.0528, the linear correlation coefficient was 0.9997, and the detection limit was 0.71μg· m L-1. The relatively standard deviations were from 0.3% to 0.7%(n=10), the recoveries of the method were from 95.6% to 101.6%(n=10).The proposed method had been applied to the determination of acetaminophen in cold medicine,and the results agreed well with those of pharmacopeia method.