用紫外分光光度法及荧光光度法研究肾上腺素在不同pH条件下的稳定性

UV-Spectrophotometric and Fluorophotometric Study on Stability of Epinephrine Under Different pH Conditions

在pH 7.45磷酸盐缓冲溶液和盐水组成的模拟生理介质中,用UV-分光光度法及荧光光度法研究了肾上腺素分子中电子对能量的传递方式及不同的pH条件对肾上腺素稳定性的影响。结果表明:在此条件下,肾上腺素的特征吸收峰位于278.0nm波长处;当激发光谱波长为279.0nm时,在314.0nm及616.0nm两波长处出现肾上腺素的荧光发射光谱峰。据此提出了测定肾上腺素的荧光光度法,其线性范围为1.80mg·L^(-1)以内,检出限(S/N=3)为2.70×10^(-4)mg·L^(-1)。试验发现:当溶液的pH值大于10时,肾上腺素被氧气氧化生成羰基化合物,致使其吸收峰发生红移及荧光峰的减弱或消失。

Under simulated physiological condition of pH 7. 45 with PBS and saline water, the energy transmission of electron pair in epinephrine molecules and the effect of different pH conditions on the stability of epinephrine were studied by UV-spectrophotometry and fluorophotometry. Characteristic absorption peak of epinephrine was observed at wavelength of 278. 0 nm, and fluorescence emission wavelength was found at 314.0 nm and 616. 0 nm when excited at wavelength of 279. 0 nrn. A method of fluorophotometric determination of epinephrine was proposed with its linearity range within 1.80 mg·L^-1 and detection limit （S/N=3） of 2. 70×10^-4mg ·L^-1. It was found that at acidity over pH 10, epinephrine was oxidized by oxygen to form carbonyI compound, leading to bathochromic shift of its absorption peak and weakening or disappearance of its fluorescence peaks.