方波伏安法测定酚酞片含量

Determination of Phenophthalein by Square Wave Voltammetry

研究了酚酞在0.5 mol/L氨水-氯化铵缓冲溶液(pH 10)介质中汞膜电极上的电化学行为,并依此建立了酚酞含量的方波伏安法测定.酚酞于-0.98 V(VS.Ag/AgCl)处出现一灵敏的阴极还原峰,峰高与酚酞的浓度在3.0×10-7-5.0×10-5mol/L范围内有良好的线性关系.方法的最低检出限为1.0×10-7mol/L,方法用于酚酞片中酚酞含量的测定,结果满意.

The electro-chemical behavior of phenophthalein has been studied in mercury film electrode, and an electro-chemical method for the determination of phenophthalein was established. In a buffer solution of NH3-NH4Cl （pH 10）, a reduction peak at -0.98 V（VS. Ag/AgCl） was observed. There was a good linear relationship between the peak height and the concentration of phenophthalein within the rang of 3.0 × 10^-7 -5.0× 10^-5 mol/L. The method was rapid, simple and accurate, and can be used for the determination of phenophthalein.