维生素c含量测定

维生素c含量测定 实验项目四、维生素C的含量测定 姓 名: 赵家熙 指导教师: 实验室: 组员:? 章恒炯 ? ? 成绩: 第三部分:实验与分析 一、原始数据: 尖椒质量:5.149 一(标定 消耗2,6-二氯酚靛酚 1 2 3 平均 对照1 对照2 对照3 平均 标定前 读数 0.153 0.22 0.281 0 0 0 标定后 读数 0.939 0.978 1.073 0.141 0.143 0.102 消耗的 量 0.786 0.778 0.792 0.785 0.141 0.143 0.102 0.128 二(滴定 消耗的2,6-二氯酚靛2%草酸 样品提取液 酚 第一次 第二次 第一次 第二次 滴定前读数(ml) 0 0 0 0 滴定后读数(ml) 0.08 0.077 1.14 1.209 消耗量(ml) 0.08 0.077 1.14 1.209 平均值(ml) 0.078 1.174 二、计算分析:,求出每100克样品中含有的维生素C 的mg数, field is downwind, brooding House separate from the breeding shed, and ... Building chicken farms must also consider the construction of chicken manure treatment facilities such as septic tanks, methane-generating pit, do not let the chicken manure directly. Five to do a disease prevention and control, do not cut corners. Built into the chicken in chicken farm, will be required to do a variety of vaccine injections and disinfection in chicken farm, do not hold the chance, and do scientific farming. Reasonable problems in building a chicken coop hen house layout, can provide a good environment for chicken, making its full productive potential, so other than in understanding the physiological characteristics of the chicken itself, and must be properly planned and constructed sheds. A chicken layout considerations 1. Sites to choose away from populated areas, traffic convenient, away from the road 2. Gaozao terrain, a lot of sunshine. Winter sun as possible, summer wind, and not after the rain water. Larger, leaving room for development 3. Abundant water resources pollution-free, easy to access, sufficient power is guaranteed 4. Building structure, the economy, saving money, and saving energy, it is facing in accordance with local environmental and physiological condition, lighting is good, easy to ventilation, easy to operate, so conducive to cooling in the summer, to insulation in winter cold 5. Layout of premises should be reasonable, do distinguish between 如上述图表中原始数据: S=0.1*1/,0.785-0.128,=0.152 W值,滴定瓶中待测样品的重量,=5.149/50=0.102 VC,mg/100g样品,=,VA-VB,*S*100/W =163.325 mg/100g样品 第四部分:课后讨论题 1、本次实验操作的注意事项。 (1)整个操作过程要迅速～防止还原型抗坏血酸被其他还原剂氧化。每次滴定过程一般不超过2min。 (2)滴定所用的染料应在1-4ml间。样品含VC太高或太低时～可酌情增减样液用量或改变提取液稀释度. (3)滴定终点以在淡红色存在15s内为准 2、指出本实验采用的定量测定维生素C的方法有何优缺点, 缺点: (1)本实验采用滴定的方法来定量测定维生素C的含量～在滴定的field is downwind, brooding House separate from the breeding shed, and ... Building chicken farms must also consider the construction of chicken manure treatment facilities such as septic tanks, methane-generating pit, do not let the chicken manure directly. Five to do a disease prevention and control, do not cut corners. Built into the chicken in chicken farm, will be required to do a variety of vaccine injections and disinfection in chicken farm, do not hold the chance, and do scientific farming. Reasonable problems in building a chicken coop hen house layout, can provide a good environment for chicken, making its full productive potential, so other than in understanding the physiological characteristics of the chicken itself, and must be properly planned and constructed sheds. A chicken layout considerations 1. Sites to choose away from populated areas, traffic convenient, away from the road 2. Gaozao terrain, a lot of sunshine. Winter sun as possible, summer wind, and not after the rain water. Larger, leaving room for development 3. Abundant water resources pollution-free, easy to access, sufficient power is guaranteed 4. Building structure, the economy, saving money, and saving energy, it is facing in accordance with local environmental and physiological condition, lighting is good, easy to ventilation, easy to operate, so conducive to cooling in the summer, to insulation in winter cold 5. Layout of premises should be reasonable, do distinguish between 过程中～因为采用的是微量滴定管～滴定的过程中因为一滴产生 的误差较大～对实验的结果有一定的影响. (2)实验中～采用过滤的方法来提取样品～样品在纱布上有较大的 残留。 (3)该实验只能测定还原型抗环血酸～不能测出具有同样生理功能 的氧化型抗坏血酸和结合行抗坏血酸。 优点: (1)本实验有很好的实践性～适合教学～方法经济快速便捷～易于 广大同学更好的理解滴定～对实验素养的提高有很大的帮助。 3、试简述维生素C的生理意义及应用情况。 生理意义:维生素C缺乏后数月～患者感倦怠、全身乏力、精神抑郁、多疑、虚弱、厌食、营养不良、面色苍白、轻度贫血、牙龈肿胀、出血～并可因牙龈及齿槽坏死而致牙齿松动、脱落～骨关节肌肉疼痛～皮肤瘀点、瘀斑～毛囊过度角化、周围出血～小儿可因骨膜下出血而致下肢假性瘫痪、肿胀、压痛明显～髋关节外展～膝关节半屈～足外旋～蛙样姿势。 应用:(1)促进骨胶原的生物合成～利于组织创伤口的更快愈合;促进胶原蛋白的合成～防止牙龈出血;促进牙齿和骨骼的生长～防止牙床出血～防止关节痛、腰腿痛。 (2)促进氨基酸中酪氨酸和色氨酸的代谢～延长肌体寿命;增强肌体对field is downwind, brooding House separate from the breeding shed, and ... Building chicken farms must also consider the construction of chicken manure treatment facilities such as septic tanks, methane-generating pit, do not let the chicken manure directly. Five to do a disease prevention and control, do not cut corners. Built into the chicken in chicken farm, will be required to do a variety of vaccine injections and disinfection in chicken farm, do not hold the chance, and do scientific farming. Reasonable problems in building a chicken coop hen house layout, can provide a good environment for chicken, making its full productive potential, so other than in understanding the physiological characteristics of the chicken itself, and must be properly planned and constructed sheds. A chicken layout considerations 1. Sites to choose away from populated areas, traffic convenient, away from the road 2. Gaozao terrain, a lot of sunshine. Winter sun as possible, summer wind, and not after the rain water. Larger, leaving room for development 3. Abundant water resources pollution-free, easy to access, sufficient power is guaranteed 4. Building structure, the economy, saving money, and saving energy, it is facing in accordance with local environmental and physiological condition, lighting is good, easy to ventilation, easy to operate, so conducive to cooling in the summer, to insulation in winter cold 5. Layout of premises should be reasonable, do distinguish between 外界环境的抗应激能力和免疫力。 (3)改善铁、钙和叶酸的利用;改善脂肪和类脂特别是胆固醇的代谢～预防心血管病。 (4)坚持按时服用维生素C～可使皮肤黑色素沉着减少～从而减少黑斑和雀斑～使皮肤白皙。 5、为何整个滴定过程不要超过2分钟, 因为还原型抗坏血酸易被氧化～空气中的氧气会氧化Vc～样品中没有抗氧化的2%的草酸Vc就更容易被氧化～所以滴定过程不要超过2分钟。 6、为什么滴定终点以在淡红色存在15s内为准, 当一种溶液滴加到另一种溶液中时,会突然打破原来溶液保持的动态平衡,在这个过程中就出现了"假变色",等半分钟就达到新的动态平衡了,颜色就不再改变了 。 7、查阅资料～介绍其他测定VC含量的方法和原理。 (1) 碘量法 原理:由于维生素C分子中的烯二醇基有极强的还原性～能被碘 氧化～用碘滴定VC field is downwind, brooding House separate from the breeding shed, and ... Building chicken farms must also consider the construction of chicken manure treatment facilities such as septic tanks, methane-generating pit, do not let the chicken manure directly. Five to do a disease prevention and control, do not cut corners. Built into the chicken in chicken farm, will be required to do a variety of vaccine injections and disinfection in chicken farm, do not hold the chance, and do scientific farming. Reasonable problems in building a chicken coop hen house layout, can provide a good environment for chicken, making its full productive potential, so other than in understanding the physiological characteristics of the chicken itself, and must be properly planned and constructed sheds. A chicken layout considerations 1. Sites to choose away from populated areas, traffic convenient, away from the road 2. Gaozao terrain, a lot of sunshine. Winter sun as possible, summer wind, and not after the rain water. Larger, leaving room for development 3. Abundant water resources pollution-free, easy to access, sufficient power is guaranteed 4. Building structure, the economy, saving money, and saving energy, it is facing in accordance with local environmental and physiological condition, lighting is good, easy to ventilation, easy to operate, so conducive to cooling in the summer, to insulation in winter cold 5. Layout of premises should be reasonable, do distinguish between EC6H6O6/C6H8O6=0.18 ,EI2/I-=0.535 终点:淀粉为指示剂～溶液出现稳定的蓝色即为终点 (2) 碘的浓度由已知浓度的Na2S2O3溶液标定 22,,,反应式: ISOISO，,，2222346 计算式: Wvc=C(I2)V(I2)M(vc)/m(vc ) *100% (3) 电位滴定法 原理:随着滴定剂的加入～由于发生化学反应～待测离子浓度将 不断变化,从而指示电极电位发生相应变化,导致电池电动势发 生相应变化,计量点附近离子浓度发生突变,引起电位的突变～ 因此由测量工作电池电动势的变化就能确定终点。 教师评阅: 签名 field is downwind, brooding House separate from the breeding shed, and ... Building chicken farms must also consider the construction of chicken manure treatment facilities such as septic tanks, methane-generating pit, do not let the chicken manure directly. Five to do a disease prevention and control, do not cut corners. Built into the chicken in chicken farm, will be required to do a variety of vaccine injections and disinfection in chicken farm, do not hold the chance, and do scientific farming. Reasonable problems in building a chicken coop hen house layout, can provide a good environment for chicken, making its full productive potential, so other than in understanding the physiological characteristics of the chicken itself, and must be properly planned and constructed sheds. A chicken layout considerations 1. Sites to choose away from populated areas, traffic convenient, away from the road 2. Gaozao terrain, a lot of sunshine. Winter sun as possible, summer wind, and not after the rain water. Larger, leaving room for development 3. Abundant water resources pollution-free, easy to access, sufficient power is guaranteed 4. Building structure, the economy, saving money, and saving energy, it is facing in accordance with local environmental and physiological condition, lighting is good, easy to ventilation, easy to operate, so conducive to cooling in the summer, to insulation in winter cold 5. Layout of premises should be reasonable, do distinguish between