中性红分光光度法测定肝素钠的研究

在pH 3.0的Britton-Robinson(B-R)缓冲溶液中，中性红与肝素钠相互作用形成复合物而导致溶液吸收光谱发生变化，用分光光度法对光谱变化进行了研究。 中性红溶液在523 nm处有一个强的特征吸收峰，当在其溶液中加入肝素钠后，溶液发生褪色现象，吸收峰强度降低，且没有新的吸收峰出现，吸光度差值(ΔA)与肝素钠的浓度成正比。 对结合反应的条件进行了优化，在最佳条件下利用溶液吸光度值的降低与肝素钠浓度的关系建立了一种测定肝素钠浓度的新方法，测定的线性范围为0.10～15.0 mg·L-1,表观摩尔吸光系数ε=2.037×106 L·mol-1·cm-1,检测限(3σ)为0.073 mg·L-1。 将该方法应用于肝素钠注射液效价的测定，结果令人满意。 用摩尔比法对复合物的结合比进行了推算，两者形成1∶3的复合物。

Spectrophotometric Determination of Heparin with Neutral Red

The interaction of neutral red and heparin was studied by UV-Vis spectrophotometry in pH 3.0 Britton-Robinson (B-R) buffer solution. Neutral red has a strong absorbance at 523 nm and the addition of heparin into neutral red solution resulted in the decrease in the absorbance value at 523 nm without the appearance of new absorbance peak. The decrease in absorbance value was linear with the concentration of heparin. The conditions for the interaction were optimized and the interferences of coexistent substances were investigated. Under the optimal conditions a linear regression equation was obtained as deltaA = 0.044 + 0.076c (mg x L(-1)) (n = 12, r = 0.997) in the range of 0.10-15.0 mg x L(-1) with the detection limit of 0.073 mg x L(-1). The molar absorptivity of the method was calculated to be 2.037 x 10(6) L x mol(-1) x cm(-1). The method was applied to determine the heparin sodium injection solution with satisfactory results. The stoichiometry of heparin with neutral red was calculated as 1 : 3.