Effect of Temperature and Cu2+ on Abscorbic Acid Stability

Effect of Temperature and Cu2+ on Abscorbic Acid Stability Effects of Temperature, pH and Cu2+ on Abscorbic Acid Stability NAME: Sophia Chai Lai Jin Objectives: To perform a selected redox titrimetric procedure. To measure the stability of ascorbic acid under various conditions. Introduction L-ascorbic acid as known as Vitamin C is an essential nutrient for humans. L-ascorbic acid is one of the most potent compounds acting as an antioxidant in biological systems by scavenging active oxygen species and free radicals. L-ascorbic acid is a well-known water-soluble antioxidant that has a whitening effect and serves as a cofactor of prolinehydroxylase to promote synthesis of collagen. Low intakes cause a nutrient deficiency disease known as scurvy. Scurvy causes general weakness, anemia, gum disease, and skin hemorrhages. The effectiveness of ascorbic acid as a food additive depends on its oxidation to dehydroascorbic acid which effectively destroys ascorbic acid. Since it is so readily oxidized, it is frequently called the most unstable vitamin. Ascorbic acid may degrade via a number of different mechanisms. Anaerobic and aerobic pathways have been identified; but when oxygen is present, oxidative degradation predominates. Factors that may influence the rate of ascorbic acid degradation include temperature, salt and sugar concentration, pH, oxygen concentration, metal catalysts, and enzymes. Apparatus Test tubes, beakers (20 and 250 mL), burets, pipets (1,5 and 10 mL), Erlenmeyer flasks (50 mL), graduated cylinders (10 and 50 mL), hot plate, boiling beads, pH meter, water bath. Materials Ascorbic acid solution (0.5 and 10 mg/mL), oxalic acid solution (0.25 M), 2,6-dichloroindophenol (dye) solution, cupric sulphate, (CuSO4.5H2O) solution (10 g/100 mL), glycine buffer (0.1 M, pH 2), carbonate buffer (0.1 M, pH 8), HCl (1 M). Experimental Procedure Abscorbic Acid Standard Curve 9 mL of oxalic acid solution and 1 mL of 1.0 M HCl was transferred to each of four Erlenmeyer flask. 0.5, 1.0, 1.5 and 2.0 mL of ascorbic acid solution (0.5 mg/mL) was added to each respectively. Each flask rapidly with dye solution was titrate until a light but distinct rose pink colour persists for at least 5 s. A volume o fdye versus miligrams of ascorbic acid was plotted. Effects of Temperature, pH and Cu2+ on Ascorbic Acid Stability 10 mL (duplicate) was prepared of each of the following solution Ascorbic acid in glycine buffer Ascorbic acid in carbonate buffer Ascorbic acid in glycine buffer + CuSO4 Ascorbic acid in carbonate buffer + CuSO4 1 mL of ascorbic acid (10 mg/mL), 0.5 mL of CuSO4 and sufficient buffer was added to bring the total volume to 10 mL and well mixed. The pH was recorded for each solution. They was cover and capped loosely and transfer to a boiling water bath. It was boiled for 15 minutes and cooled. Titration was done. Results: Table 1 : Volume of dye vs miligrams of ascorbic acid Ascorbic acid (0.5 mg/mL) Ascorbic acid in mg Volume of dichloroindophenol used (mL) 0.5 0.25 30.4 1.0 0.5 57.1 1.5 0.75 82.7 2.0 1.0 114.1 Table 2: pH value of each solution Solution pH value 1st set 2nd set Ascorbic acid + glycine 2.06 2.09 Ascorbic acid + carbonate 7.24 7.27 Ascorbic acid + glycine + CuSO4 1.98 2.00 Ascorbic acid + carbonate + CuSO4 6.17 6.22 Table 3: Volume of dye vs different solutions Solution Volume of dichloroindophenol used (mL) Ascorbic acid + glycine 5.8 Ascorbic acid + carbonate 3.3 Ascorbic acid + glycine + CuSO4 2.6 Ascorbic acid + carbonate + CuSO4 1.6 Calculation Average amount of ascorbic acid to titrate with dichloroindophenol in 1 mL Y = 113.21x 1 = 113.21x X = 0.0088 mg 1 mL of dichloroindophenol is required to titrate with 0.0088 mg of ascorbic acid Total volume of ascorbic acid solution = 10 mL Ascorbic acid + glycine solution required 5.8 mL of dichloroindophenol: 0.0088 mg X 5.8 = 0.05104 mg Concentration of ascorbic acid = 0.005104 mg/mL Ascorbic acid + carbonate required 3.3 mL of dichloroindophenol: 0.0088 mg X 3.3 = 0.02904 mg Concentration of ascorbic acid= 0.0029 mg/mL Ascorbic acid + glycine + CuSO4 required 2.6 mL of dichloroindophenol: 0.0088 mg X 2.6= 0.02288 mg Concentration of ascorbic acid = 0.002288 mg/mL Ascorbic acid + carbonate + CuSO4 required 1.6 mL of dichloroindophenol: 0.0088 mg X 1.6= 0.01408 mg/mL Concentration of ascorbic acid = 0.001408 mg/mL Discussion In this experiment, redox iodometric titration assay was used to determine the amount of concentration of ascorbic acid in each buffer solution. CuSO4 act as the oxidizing reagent in the reaction. Firstly, the dichloroindophenol act as the blue dye will oxidized the ascorbic acid when titration begin. The ascorbic acid will be oxidized into another form which is called dehydroascorbic acid. The following figure shows the equation of redox reaction of ascorbic acid and converted to dehydroascorbic acid in the titration. In acid condition, the blue dye will turn the solution into pinkish colour, if the ascorbic acid is present, it will reduce the solution back into colourless compound. The higher the concentration of ascorbic acid, the more dichloroindophenol is needed to oxidize it. Until the titration end point is reached, a persist pink colour solution will be obtained. This indicates that the availability of ascorbic acid has used up for reduction and being oxidized quantitavely by dichloroindophenol. Therefore, from the result in part A standard curve calibration, a straight linear line was achieved. The 2.0 mL of ascorbic acid solution (0.5 mg/mL) required a huge amount of dichloroindophenol to neutralize it. From the result obtained, the ascorbic acid-glycine solution tend to have higher concentration of ascorbic acid. Meanwhile in ascorbic acid-carbonate solution has a lower concentration of ascorbic acid. This might due to in alkaline condition it will be more easily to oxidized into dehydroascorbic acid. In alkaline condition, the O2 will act as the oxidant to breakdown the ascorbic acid and destabilize it. Therefore, a slightly acidic pH, the antioxidant properties of ascorbic acid can be maintained. Moreover, in the presence of CuSO4 will degrade the ascorbic acid easily as CuSO4 is a strong oxidizing agent. Cu2+ will catalaze the oxidation and heating also will increase the rate of oxidation. However, at a slight acidic pH such as in citrus juice, the vitamin is more stable. Besides, thermal treatment to the ascorbic acid can degrade and destruct the antioxidant properties of the structure. In boiling water bath, most of the ascorbic acid are believed to be degraded. Therefore, the amount of the concentration of ascorbic acid are found to be lower than the beginning of the experiment. Conclusion The higher the concentration of ascorbic acid in a solution, the more amount of dichloroindophenol are required to neutralized it. In a very acidic condition, it will degrade the ascorbic acid faster. However in a neutral or alkaline condition in the presence of air, the ascorbic acid will oxidized fast due to the O2 which is an oxidant. High temperature can degrade the antioxidant properties of the vitamin C. References http://www.nlm.nih.gov/medlineplus/ency/article/000355.htm http://chemistry.about.com/od/demonstrationsexperiments/ss/vitctitration_4.htm http://www.sussexvt.k12.de.us/science/Textbook/LIM_LowRes_Unsecured/NCInv13D.pdf Questions Explain the difference in the results between the ascorbic acid-glycine and the ascorbic acid-carbonate buffers, and the effect of pH on ascorbic acid. The ascorbic acid-glycine solution tend to have higher concentration of ascorbic acid. Meanwhile in ascorbic acid-carbonate solution has a lower concentration of ascorbic acid. This might due to in alkaline condition it will be more easily to oxidized into dehydroascorbic acid. In alkaline condition, the O2 will act as the oxidant to breakdown the ascorbic acid and destabilize it. Therefore, a slightly acidic pH, the antioxidant properties of ascorbic acid can be maintained. Explain the difference in the results between ascorbic acid-glycine buffer and the ascorbic acid-glycine buffer with CuSO4; between ascorbic acid-carbonate buffer and the ascorbic acid-carbonate buffer with CuSO4 model systems. The presence of metal ions such as copper and iron increase the rate of oxidation of ascorbic acid. CuSO4 is strong oxidizing agent. Ascorbic acid form complex with metal ions and reduce metal ion into metal. Therefore, the addition of CuSO4 has lowered the amount of dichloroindophenol which required to titrate with the ascorbic acid solution.

Personal development planning Essay

I am 24 years old and married to my husband Paul we live in Maybole in a two bedroom cottage. I left school at 16 with standard grade level English, maths, history, French and music. My first job was in a nursing home it was then I realised how much I enjoyed working in care and caring for people. I worked in the nursing home for 2 years then left to be an activity’s co-ordinator in a day care centre in Prestwick where I would plan daily activity’s and outings for clients who came for respite day-care the centre sadly closed down after 3 years. I found a part time job in a local pub but I didn’t enjoy it as much as caring I worked in the pub for 2 years until I found a job working for a homecare company I enjoyed but found the hours unsociable it was then I decided to apply for college. I applied for N.C social care and was placed on the reserved list due to the course being full then a week after the course started I got a phone call to start. I attended college from September to june working threw my course studying and passed all my exams. I also attended a work placement at Hansel village respite cabin which I enjoys working with the clients as id never worked with adults with learning difficulties. I was offered a permanent job with Hansel after I left but sadly couldn’t take the job offer up as I had applied to do HNC and Hansel could only offer me 30 hours per week. Whilst doing my NC I enjoyed the subject mental health and decided then that I would like to become a mental health nurse. My hopes are that I graduate with my HNC and can apply to university and get a degree. Step 2: Broad objective – where am I going next? Whilst completing this unit in Personal Development Planning, I have opted to focus on the following area of development my ability to write reports and essays having done an N.C in social care last year I had to do a few reports and essays and realised that I don’t structure them properly this is something I need to practice and develop my skills and abilities in doing this. I would like to progress and graduate from college with my HNC in social care and apply to university of the west of Scotland and do a degree in mental health nursing and work in a psychiatric hospital. Further development of core/key skills Step 3: Self appraisal Personal skills, qualities and contexts Core skill Evaluation Evidence to support evaluation Communication Good When doing an NC in social care one of the tasks I had to do was a presentation in front of the class I became really nervous and didn’t make a lot of eye contact. This is something I would like to work at and concentrate on in the future when delivering presentations. Numeracy Poor Numeracy was apart of my NC course last year and I failed two attempts at an exam working out percentages and doing box plots but I find with extra studying and breaking it down I can complete some numeracy tasks. IT Average I received a standard grade for admin at school this gave me some knowledge on IT skills. On my college course last year I done IT at a higher level where I was shown how to use different search engines and how to type up reports essays and save my work. Problem solving Poor When faced with situations I tend to panic rather than look for solutions to  resolve problems. I feel this is something I can develop in. Working with others Good Threw my recent jobs as a carer, bar maid, activity’s coordinator I have had to work as part of a team to deliver my work and do the best in my job. I also work with others at college to do research on my subjects this is something I enjoy doing. Personal qualities I am a hard working reliable individual. With an NC in social care this has given me a wide knowledge of sociology, psychology and helped me realise my own personal values and principles. I have developed my caring practical skills threw working in in many different care aspects and work placements. I am an honest and trustworthy person who enjoys working as part of team and also on my own initiative. Knowledge and understanding I have a wide knowledge of care and an understanding of my own personal values and principles that I try and introduce when caring for individuals with different needs. I also have a basic knowledge of sociology and try to have an understanding in which way society works. And my basic knowledge of psychology helps me understand peoples behaviours. Technical skills I feel my technical skills can be worked on and developed threw out this course. Threw work and work placements I have a basic knowledge on moving and handling. I also have basic computing skills. Contexts, other factors to consider Step 4: Setting personal objectives Personal objectives — prior to interview with tutor Short-term (this year) I hope to pass my course and gain my HNC in social care. I also hope to gain knowledge and develop new skills threw out the year in all aspects of social care and on college work placement. Medium-term (next year) I hope to be able to apply to university and have enough qualifications and skills and to be able to stay focused on my work and my short and long term goals to be achievable. Long-term I hope to have gained a degree in mental health nursing and be in a job I enjoy doing that helps me stay motivated.

The process of developing and designing products

The process of developing and designing products has taken a sharp change in the last couple of years. Companies are being pushed by demanding global customers and are being challenged by rapid change of technology. Manufacturers have had to increase the speed of design cycles while at the same time cut the cost of development and manufacture. They must ensure the product takes full advantage of the latest and best technology. Leading companies have found that obstacles in the market today are far too rigorous to overcome on their own. This process of design and development of products has never been so competitive and daunting. However, it is more critical for future success. The Success of modern day companies is due to help from a resource that has been present since the early days of the company. The answer is suppliers. In some industries suppliers are taking on responsibility for designing parts, components, materials, assemblies, and even complete systems for automobiles, computers and other products. Leading manufacturers are using their supply bases as a key element of their product design strategies, and it’s paying off in a big way. In other words the old saw â€Å"Slow and sure wins the race† no longer holds. Speed is competitive edge today s business needs to succeed. Including suppliers in the manufacturing process adds to the clock-speed of a company. The Honda Motor Company is one such company that has recognized this need for speed and has thus adjusted its production to accommodate. The Honda Motor Company is one of the world s most well known producers of motor vehicles. The Company itself is based in Japan, but it had branches all over the world. From a simple start, Honda has grown to one of the world s most successful motoring companies, selling products in almost 200 countries. Honda has set new standards in vehicle production and design. From the Civic to ongoing participation in automotive racing, Honda s spirit of challenge and commitment forms the basis for every Honda project. Honda’s new â€Å"world platform† strategy will produce four variants of the new mid-size Accord platform. Honda s Research and development team found that the easiest way of producing their most popular make of car, the Accord, was to produce a world platform. This platform is an Accord chassis around which different accord bodies are built. For example; The Accord built for America will be larger than the one built in Japan because there is a market for larger cars. The one built in Europe will narrower so that it may compete with other cars on the European market. Essentially the Accord platform is universal. The car s appearance changes due to its location around the world. Accords will be produced in 11 and sold in 100 countries.

Analysis Of The Movie The And Timelessness Of The Film

The placelessness and timelessness of the film also allows the creators to disregard archaeological accuracy when drawing inspiration from Incan art and architecture for the animation of the film. The Inca civilization developed a distinct â€Å"abstract† and â€Å"geometrical† style of art (Zuidema, 2). Drawing upon this, The Emperor’s New Groove’s creators claimed to use the Inca art pieces â€Å"as inspiration and use their designs in other ways† (Silverman, 309). While the creators did base some of the film’s animations off of authentic Incan art, they do admit to altering nearly all of it. This fragments the archaeological information that could be provided by these art pieces by using them out of context (Silverman, 301). For example, using a†¦show more content†¦The filmmakers, however, are able to do include all of these different types of art because of the timelessness and placelessness of the film. They can draw inspiratio n from any civilization without worrying about archaeological inaccuracy because total accuracy is not their intention. As for the architecture in the film, the creators use the same strategy of starting with accurate information as the basis, but altering it until it is nearly unrecognizable. Many of the buildings shown in the film are Kuzco’s palaces, which are entirely gold and have the design of large, exaggerated faces. It is possible that the use of gold and the mammoth faces could be an indirect reference to the Incan worship of the Sun God Inti. However, the architecture of these buildings is not archaeologically accurate and is instead a result of the creators’ alterations of Incan art and designs. One additional archaeological misstep on the part of the creators is the language of the movie. The main language of the Inca civilization was Quechua, while The Emperor’s New Groove is entirely in English. 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