三波长分光光度法快速测定青苹果中的苹果酸

Fast ddetermination of malic acid in greenapple by three-wavelength spectrophotometry

为建立快速测定青苹果中苹果酸的三波长分光光度法,利用孔雀石绿能在弱酸性的Tris—盐酸缓冲溶液中与苹果酸反应,在可见光区生成具有3个明显正吸收峰（分别位于568,644,424nm波长处）的绿色离子缔合物,对用三波长法测定苹果酸进行了研究,并考察了适宜的反应条件及吸收光谱特征。结果表明,用三波长叠加法测定,表观摩尔吸光系数（κ）为5.88×10~4 L/（mol·cm）,苹果酸的质量浓度在0.008~1.900 mg/L时服从朗伯—比尔定律,定量限为0.003 2g/100g,样品加标回收率为98.23%~102.9%,相对标准偏差为1.8%~2.4%。该法可用于青苹果中苹果酸的测定。

A triple wavelength spectrophotometry to measure malice acid in green apples was established in this study.The reaction between malic acid and tris-hydrochloric acid buffer solution of malachite green showed that a green ionic association complex with three positive absorption peak locating in 568 nm,644 nm and424 nm,respectively,could be found in visible light generated area.Moreover,the malic acid with triple wavelength spectrophotometry and its related reaction condition and absorption spectral character were investigated.The result showed that the molar absorption coefficient of performance was 5.88×10~4 L/（mol·cm）,and the quality concentration of malic acid was found to be 0.008~1.900mg/L,conforming to Lambert-Beer＇s Law.It was also found that the limit of quantitation was 0.003 2g/100 g,and the adding standard recovery rate was 98.23% to 102.9%,with a relative standard deviation at1.8% ~2.4%.This method could be used for the determination of malic acid in green apple.