促进龙胆紫褪色光度法测定饲料中牛磺酸含量

Spectrophotometric determination of taurine content in feed using promoting of gentian violet oxidation

根据牛磺酸具有促进高碘酸钾氧化龙胆紫褪色的原理,考察酸度、高碘酸钾用量、龙胆紫用量、温度和时间对反应的影响,建立分光光度法测定饲料中牛磺酸的新方法。结果表明：最佳反应条件为在10ml比色管中加入pH1.99盐酸-乙酸钠缓冲溶液1.0ml、2.5×10-3 mol/L高碘酸钾溶液1.0ml和2.5×10-4 mol/L龙胆紫溶液1.0ml,室温下反应11min。在波长570nm处,吸光度减小值与牛磺酸质量浓度在0~0.25μg/ml范围内呈良好的线性关系,表观摩尔吸光系数为3.88×105 L/（mol·cm）,检出限为1.91μg/L;结合超声波提取和离子交换法预分离技术,采用牛磺酸促进高碘酸钾氧化龙胆紫褪色光度法测定饲料中牛磺酸含量,结果与高效液相色谱法一致,标准偏差为0.82%~1.29%（n=5）,回收率为98.6%~101.9%。

This experiment was conducted to establish a new spectrophotometric method for determination of taurine in feed.Trace taurine has promotive effect on the fading reaction of potassium periodate oxidizing gentian violet.The effect of acidity,potassium periodate and gentian violet dosage,temperature and time on the reaction was studied.The results showed that the optimal reaction conditions were given as follows：in a 10 ml colorimetric tube,1.0ml of hydrochloric acid-sodium acetate buffer solution at pH 1.99,1.0ml of 2.5×10-3 mol/L potassium periodate solution and 1.0ml of 2.5×10-4 mol/L gentian violet solution were added.Reaction temperature was room temperature,and reaction time was 11 min.At the wavelength of570 nm,the value of the absorbance decreased linearly with taurine concentration in the range of 0~0.25g/ml.The apparent molar absorption coefficient was 3.88×105 L/（mol·cm）,and the detection limit was 1.91μg/L.Combined with ultrasonic extraction and ion exchange method of sample treatment,the spectrophotometric method by taurine promoting the fading reaction of potassium periodate oxidizing gentian violet was applied to the determination of taurine content in feed.The results agreed well with those obtained by high performance liquid chromatography.The relative standard deviation was 0.82% ~1.29%（n = 5）,and the recovery was 98.6%~101.9%.