2,4-二硝基苯肼法测定果蔬VC含量条件探索

Study on the Factors Affecting the Determination of VC Content in Fruits and Vegetables by Method of 2, 4-dinitrophenylhydrazine

对2, 4-二硝基苯肼法测定果蔬VC含量的条件进行探索。结果表明,活性炭最佳用量1.8～2.2 g;显色剂2, 4-二硝基苯肼最佳用量2.0 mL,显色时间3～3.5 h;测定波长523 nm,且在2 h内吸光度无显著变化;抗坏血酸质量浓度在0～80μg/m L范围内遵守朗伯-比尔定律,表观摩尔吸光系数ε=2.455×10~3 L/(mol·cm),桑德尔灵敏度S=0.071 74。利用所得出的试验条件测定西红柿、辣椒、草莓和樱桃中VC含量,与碘量法和2, 6-二氯酚靛酚法相比,试验结果令人满意。

Factors affecting the determination of VC content in fruits and vegetables by method of 2, 4-dinitrophenylhydra zineorthogonal were studied. The results showed that the optimum dosage of activated carbon was 1.8-2.2 g, the optimum dosage of 2, 4-dinitrophenylhydrazine orthogonal was 2.0 mL, coloration time was 3-3.5 h, the detection wavelength was 523 nm, and there were no significant changes within 2 h. The concentration of ascorbic acid in the range of 0-80 μg/mL obeyed Lambert-Beer Law, apparent molar absorption coefficient ε was 2.455×10~3 L/(mol·cm), and Sandel sensitivity S was 0.071 74. The contents of VC in tomatoes, peppers, strawberries and cherries were determined by the experimental condition. The results were satisfactorily compared with iodometry and 2, 6-dimethylphenyl pentachlorophenol titration method.