脱色剂对2,6-二氯靛酚滴定法测定抗坏血酸含量的影响  

Effect of Decolourising Agents in the Determination of Ascorbic Acid by Titration with 2,6-Dichloroindophenol

作　　者：王文宇 郭彬 阎小青 WANG Wenyu;GUO Bin;YAN Xiaoqing(School of Public Health,Shanxi Medical University,Taiyuan 030001,China)

机构地区：[1]山西医科大学公共卫生学院,山西太原030001

出　　处：《食品安全导刊》2024年第19期82-87,91,共7页China Food Safety Magazine

摘　　要：目的:探究2,6-二氯靛酚滴定法中脱色剂对抗坏血酸含量的影响,为脱色剂的正确使用提供指导。方法:采用3种常用脱色剂白陶土、硅胶、活性炭,分析脱色剂用量和脱色时间在不同浓度抗坏血酸溶液中对抗坏血酸吸附的影响,并选择深色水果脐橙和浅色水果猕猴桃加以验证,对脱色条件进行优化。结果:3种脱色剂均对抗坏血酸具有吸附作用,吸附能力排序为活性炭>>白陶土>硅胶。在高浓度抗坏血酸溶液中(1 mg·mL^(-1)),白陶土和硅胶用量的变化对抗坏血酸吸附率无显著影响。而在低浓度抗坏血酸溶液中(0.1 mg·mL^(-1)、0.05 mg·mL^(-1)),吸附率随脱色剂用量的增加而增加,30 min时白陶土抗坏血酸吸附率为6.92%~23.32%,硅胶抗坏血酸吸附率为7.88%~8.82%。活性炭在低浓度和高浓度抗坏血酸溶液中吸附力均最强,30 min时抗坏血酸吸附率在74.17%~100%。在测定水果滤液中抗坏血酸含量时,抗坏血酸吸附率随脱色剂用量的变化趋势和0.1 mg·mL^(-1)抗坏血酸溶液一致,活性炭、白陶土、硅胶的抗坏血酸吸附率分别为64.78%~95.85%、3.32%~13.29%、4.84%~6.63%,且脱色效果排序为白陶土>活性炭>硅胶。经优化,每克水果样品白陶土用量0.8 g,脱色时长15 min为最佳测定条件。结论:在使用2,6-二氯靛酚滴定法测定抗坏血酸含量时推荐使用白陶土作为脱色剂,为了减少其对抗坏血酸的吸附,在使用时要尽量减少用量和脱色时长。Objective:To investigate the effect of decolourising agents on the determination of ascorbic acid with 2,6-dichloroindophenol titration method,and to provide guidance for the correct use of decolourising agents.Method:Three commonly used decolorants,white clay,silica gel and activated carbon were selected,and the effects of their decolorant dosage and decolorization time on the adsorption of ascorbic acid in the ascorbic acid solutions with different concentrations were anlyzed.The dark-colored fruits of navel oranges and light-colored fruits of kiwifruit were selected for validation,and the conditions of the decolorization were optimized.Result:All three decolourising agents adsorbed ascorbic acid,and the adsorption capacity was ranked as follows:activated carbon was much larger than white clay and larger than silica gel.In the high concentration of ascorbic acid solution(1 mg·mL^(-1)),there was no significant difference in the adsorption rate of ascorbic acid using different dosage of white clay and silica gel.While in the low concentration ascorbic acid solution(0.1 mg·mL^(-1),0.05 mg·mL^(-1)),the adsorption rate increased with the increase in the amount of adsorbent,ranging from 6.92%to 23.32%for different dosages of white vitrified clay and 7.88%to 8.82%for silica gel when adsorbed for 30 min.Activated carbon was strongly adsorbed ascorbic acid in both low and high concentration ascorbic acid solutions,with adsorption rates ranging from 74.17%to 100%when adsorbed for 30 min.In the determination of ascorbic acid content in the fruit filtrate,the trends of ascorbic acid adsorption rate varied with the dosage of the three decolourants were consistent with that in the 0.1 mg/mL ascorbic acid standard solution.The adsorption rates for ascorbic acid of activated carbon,white vitrified clay and silica gel in the fruit filtrate ranged from 64.78%to 95.85%,3.32%to 13.29%and 4.84%to 6.63%,respectively.The decolourisation effect is ranked as follows:white clay is better than activated carbon and better than silica g

关 键 词：2 6-二氯靛酚法 脱色剂 抗坏血酸 吸附率 

分 类 号：TS255.7[轻工技术与工程—农产品加工及贮藏工程] O655.2[轻工技术与工程—食品科学与工程]