将土霉素盐酸盐100～1000μg 置于25 ml量瓶中,加2 ml pH 3.8醋酸钠-醋酸缓冲液,用水稀释至刻度,以500 nm/min 扫描速度在230～500 nm 间记录样品的吸收峰谱,于光谱图上选取17个试验点而使之平滑,△γ=2 nm,记录下一阶导数图谱。在最大波长376 nm 处的一阶导数信号,用测量峰 The oxytetracycline hydrochloride 100 ~ 1000μg 25ml volumetric flask, add 2 ml pH 3.8 sodium acetate - acetate buffer, diluted with water to the mark, 500 nm / min scanning speed at 230 ~ 500 nm between the sample recording Of the absorption peak spectrum, in the spectrum selected 17 test points and make it smooth, △ γ = 2 nm, record the next derivative spectrum. The first derivative at the maximum wavelength of 376 nm is measured with a peak