采用漫反射傅里叶变换红外光谱法测定注射液中维生素C的含量。将稀释后的注射液直接注射到溴化钾基质中,烘干、研磨、过筛。以波数1 702 cm-1酯羰基伸缩振动吸收峰作为定量吸收峰,在波数1 685~1 736 cm-1范围内以峰面积积分测量吸光度。以维生素C钠为标准物质。维生素C钠的线性范围为0.2%~2.0%,方法的检出限(3s/k)为0.64 mg·g-1。方法应用于维生素C注射液的测定,测定值与碘量法的测定结果一致,测定值的相对标准偏差(n=10)在1.9%~2.5%之间。

Diffuse reflectance FTIR spectroscopy was applied to the determination of vitamin C in injections. Diluted injection liquor was directly injected into the matrix of KBr, which was then dried, ground and sieved successively. The absorption peak of C=O stretching at 1 702 cm-1 was selected for quantitative analysis. Absorbance in terms of peak area was measured in the region of wave numbers 1 685-1 736 cm-1. Sodium ascorbate was used as standard substance. Linearity range of sodium ascorbate was found between 0.2%-2.0% with detection limit (3s/k) of 0.64 mg·g-1. The proposed method was applied to the analysis of vitamin C injections, giving results in consistency with the values obtained by iodometric method. Values of RSD′s (n=10) found were in the range of 1.9%-2.5%.