双波长叠加吸收光谱法测定药物中的酒石酸美托洛尔

建立了快速、准确测定药物中酒石酸美托洛尔的双波长叠加可见吸收光谱法。在pH 4.55的酸性Tris-盐酸介质及586~740 nm波长范围内,偶氮氯膦Ⅲ与酒石酸美托洛尔反应生成具有两个明显正吸收峰的离子缔合物,最大正吸收波长位于614 nm,次大正吸收波长位于664 nm,表观摩尔吸光系数(κ)分别为6.03×10~4L/(mol·cm)(614 nm)和5.37×10~4L/(mol·cm)(664 nm),酒石酸美托洛尔的质量浓度在0.2~8.6 mg/L范围内服从朗伯-比尔定律,检出限为0.13 mg/L(614 nm)和0.15 mg/L(664 nm)。当采用双波长叠加法测定时,其表观摩尔吸光系数(κ)可达1.14×10~5L/(mol·cm),检出限为0.072 mg/L。该文同时探讨了显色反应的适宜条件、共存物质的影响及吸收光谱特征。实验发现,该反应体系的单波长及双波长叠加吸收光谱法的表观摩尔吸光系数可达5.37×10~4~1.14×10~5L/(mol·cm),方法可用于市售药物中酒石酸美托洛尔含量的测定,加标回收率为98.0%~101%,相对标准偏差(n=6)为1.8%~2.3%。

Determination of Metoprolol Tartrate in Drug by Dual-Wavelength Superposition Absorption Spectrometry

A new dual-wavelength superposition absorption spectrometry was established for the rapid and accurate determination of metoprolol tartrate in drug.In pH 4.55 acidic Tris-hydrochloric acid media and 586 nm-740 nm,metoprolol tartrate reacted with chlorophosphonazo Ⅲ to form an ionic association complexes with two obvious positive absorption peak.The maximum positive absorption wavelength located at 614 nm,and the second largest positive absorption wavelength was at 664 nm.The apparent molar absorptivity(κ) were 6.03 × 104 L/(mol · cm) (614 nm) and 5.37 × 104 L/(mol · cm) (664 nm),respectively.Metoprolol tartrate obeys Lombard Beer's law in the range of 0.2-8.6 mg/L,and the detection limits were 0.13 mg/L(614 nm) and 0.15 mg/L(664 nm),respectively.When the double wavelength superposition absorption spectrometry was used to determine the concentration of metoprolol tartrate,its apparent molar absorptivity (κ) could be achieved to be 1.14 × 105 L/(mol · cm),and the detection limits was 0.072 mg/L.The optimum chromogenic reaction conditions,effects of the coexistence material and absorption spectral characteristics were studied.It was found that the apparent molar absorptivities for the single wavelength and dual wavelength superposition absorption spectra of the reaction system were 5.37 × 104-1.14 × 105 L/(mol · cm).The method was applied in the determination of the content of metoprolol tartrate in commercially available metoprolol tartrate medicine with the spiked recoveries and RSD (n =6) found were in the ranges of 98.0％-101％ and 1.8％-2.3％,respectively.