建立了简便、快速、灵敏的测定药物中吡哌酸的双波长负吸收光谱法。在pH 6.63的酸性介质中，吡哌酸与亮绿反应，在500~700 nm范围内生成具有2个较强负吸收峰的绿色二元离子缔合物，2个负吸收峰分别位于578 nm和648 nm，表观摩尔吸光系数（κ）分别为7.22×10⁴ L/（mol·cm）（578 nm）和7.81×10⁴ L/（mol·cm）（648 nm）。当用双波长叠加法负吸收光谱法测定时，其表观摩尔吸光系数（κ）可达1.50×10⁵ L/（mol·cm），吡哌酸的质量浓度在0~5.5 mg/L范围内与吸光度绝对值（|A|）呈线性关系，并服从朗伯-比尔定律。将双波长法用于市售吡哌酸片和胶囊中吡哌酸的测定，加标回收率和相对标准偏差RSD（n=5）分别为97.2%~103%和2.3%~2.6%。

A simple,rapid and sensitive dual wavelength negative absorption spectroscopy for the determination of pipemidic acid in drugs is established.In an acidic media of pH=6.63,pipemidic acid reacts with brilliant green to form a green binary ion association complexes with two strong negative absorption peaks in the range of 500 to 700 nm.The negative absorption peaks are located at 578 nm and 648 nm,respectively,and their apparent molar absorptivity (κ) are 7.22×10⁴ L/(mol·cm) for 578 nm peak and 7.81×10⁴ L/(mol·cm) for 648 nm peak,respectively.When the double wavelength superposition negative absorption spectrometry is used for the determination of pipemidic acid,its apparent molar absorption coefficient (κ) can achieve 1.50×10⁵ L/(mol·cm).The mass concentration of pipemidic acid in the range of 0-5.5 mg·L^-1 is linearly related to the absolute value of absorbance (|A|) and follows Lambert-Beer law.The recoveries and relative standard deviations RSD(n=5) are 97.2%-103% and 2.3%-2.6%,respectively when the dual wavelength method is applied to determine the content of pipemidic acid in commercially available pipemidic acid tablets and capsules.

肖双宏(1997-),女,本科,研究方向为分子光谱分析,xiaoshuanghong2018@163.com