利用在pH 1～6范围内尼泊金乙酯的吸收光谱与pH值无关,而磺胺醋酰钠发生较大变化的特性,将用0.1mol/L 盐酸稀释的试样作参比液,用 pH 5.8缓冲液稀释的试样作样品液,在λ 257±1nm,223±1nm 处分别测定其吸收度求出ΔA。浓度与 AA 的相关系数γ=0.9999,平均回收率为99.58%;c.v.=0.63%。 Using the absorption spectrum of ethylparaben in the range of pH 1 ~ 6, which has nothing to do with the pH value, and the sulfatacetyl sodium changed greatly, a sample diluted with 0.1mol / L hydrochloric acid was used as reference solution, The sample diluted with pH 5.8 buffer was taken as the sample solution and the absorbance was measured at λ 257 ± 1 nm and 223 ± 1 nm respectively to obtain ΔA. The correlation coefficient between concentration and AA γ = 0.9999, the average recovery was 99.58%; c.v. = 0.63%.