2.5次微分极谱法测定药物中的叶酸

Determination of folic acid by 2.5th-order derivative polarography

拟定了叶酸的 2 .5次微分示波极谱测定新方法。在 HAc-Na Ac( p H=5.6)缓冲溶液中 ,叶酸产生一灵敏的极谱还原波 ,峰电位 Ep=-0 .70 V( vs.SCE) ,其 2 .5次导数峰峰电流 ep″与叶酸浓度在 2 .0× 1 0 - 8～ 4.0× 1 0 - 6mol/ L范围内呈线性关系 ( r=0 .9988,n =8) ,检出极限为 4.0× 1 0 - 9mol/ L。 1 3次平行测量 4.0× 1 0 - 7mol/ L叶酸的峰电流 ,所得 RSD为 1 .2 %。

A method for the determination of folic acid is proposed. In HAc NaAc (pH=5.6) buffer solution, folic acid yielded a reduction wave with peak potential -0.70 V (vs. SCE). Using 2.5th order derivative polarography achieved higher sensitivity. The 2.5th order derivative peak current of the reduction wave is rectilinear to folic acid concentration in the range of 2.0×10 -8 ～4.0×10 -6 mol/L (r=0.998 8, n=8). The detection limit is 4.0×10 -9 mol/L. Relative standard deviation (RSD) is 1.2% by performing 13 parallel measurements of 4.0×10 -7 mol/L folic acid. The method had been used to the determination of folic acid in tablets.