Chromatography Separation of Dye Mixture

Chromatography Separation of Dye Mixture Chromatography is a technique used to separate the components of a mixture 1. There are two phases in chromatography, the stationary phase (absorbed solvent) and the mobile phase (moving solvent). The process of chromatography involves passing a mixture dissolved in a mobile phase through a stationary phase. Since each phase has a different distribution coefficient, the components travel at a different rate and thus get separated. The two commonly used techniques of chromatography are thin layer chromatography, TLC, and column chromatography. Thin layer chromatography is used to determine the purity of a substance, to identify, and is used to determine solvent system for separations of mixtures. This technique is especially useful in determining optimum conditions for separating compounds by column chromatography 1. On the other hand, column chromatography is used on a much larger scale. It is used to separate mixtures made of two or more compounds. During column chromatography, thes e components are separated many times between the stationary phase and the mobile phase. The purpose of conducting this experiment was to determine the suitable solvents for the various components in a mixture of 1:1 methylene blue and fluorescein dye. The two eluting solvents used in the experiment were 1:12:14 mixture of K2SO4: CH3CN and 95% ethanol. The experiment allowed us to identify the effects of the two different solvents on the different dye mixtures. The effect can be observed from the retention factor, Rf, which is a ratio of the distance traveled by the sample to the distance traveled by the solvent 2. Different conclusions can be drawn up from the Rf value, a high Rf value would indicate that the substance is less polar and has traveled a greater distance and a low Rf value would indicate the opposite. The two dye mixtures used in the experiment are methylene blue and fluorescein. Based on the properties of the two substances, the alternate hypothesis that methylene blue will have a higher retention factor compared to fluorescein can be stipulated. It can also be hypothesized that since fluorescein is more polar than methylene blue it will dissolve in the more polar solvent and travel a greater distance. Results The distance traveled by each dye mixture, the R- value, is shown in Table 1 and Table 2. These R-values are used to calculate the Rf values for each mixture, which are also shown in Table 1 and Table 2. The Rf values for the mixtures in 1:12:14 K2SO4:H2O:CH3CN are 0.76, 0.70 and 0.75 for fluorescein, dye mixture and methylene blue respectively. The Rf values for the mixtures in 95% ethanol are 0.057, 0.32 and 0.34 for fluorescein, dye mixture and methylene blue respectively. As indicated in the tables above, both the eluting solvents, 1:12:14 K2SO4:H2O:CH3CN and 95% ethanol separated impurity on the TLC plate. The Rf values are similar with the Rf values found by other experiments. M.B Naff and A.S Naff found the Rf values of fluorescein to be 0.85 and the Rf value of methylene blue to be 0.02, when the eluting solvent used is a ratio of 2:2: 1 methyl ethyl ketone: acetic acid: isopropyl alcohol 1. Table 3 shows the elution of the fluorescein and methylene blue, with methylene blue eluting first followed by fluorescein. Discussion Thin layer chromatography was used to determine the most suitable solvent system for the separations of the mixtures. From the data gathered, it was observed that both fluorescein and methylene blue traveled a further distance on the chromatogram when the solvent 1:12:14 K2SO4: H2O:CH3CN was used, as compared to the distance traveled when the solvent being used was 95% ethanol. This shows that the solvent 1:12:14 K2SO4: H2O:CH3CN is more polar than 95% ethanol since in the solvent 1:12:14 K2SO4: H2O:CH3CN both the polar dye mixtures dissolve (like attracts/ dissolves like) and travel a further distance. The polarity of the elutent forces the compounds to the top of the place, because the compounds dissolve well and do not interact with the stationary phase. In TLC, the adsorbent (stationary phase) is thinly spread onto a flat sheet of supportive plastic. The mixture to be separated is applied onto the stationary phase about 1 cm from the bottom of  the chromatographic sheet. The sheet is then placed into a developing chamber containing the  mobile phase. The mobile phase rises up the chromatography sheet by capillary action. As the  mobile phase proceeds up the sheet, the components of the mixture are retained in various  degrees by the stationary phase. The chemical composition of the stationary phase and the  mobile phase play a significant role in how far the components travel up the chromatographic  sheet. In column chromatography, a glass column is packed with a solid stationary phase. The mixture  to be separated is applied at the top of the column. The mobile phase descends by gravity  through the column. The components of the mixture to be separated have different properties. The rate at which the components descend through the column depends on several factors. The  component is retained by the stationary phase to a certain extent depending on the properties of  the stationary phase and the properties of the component. The solvation power of the solvent also  affects the rate of elution. The rule of like dissolves like applies here. The individual  components, with different affinities for the stationary phase and the mobile phase, are  continuously absorbed onto the stationary phase, solvated by the mobile phase eluting through  the column, reabsorbed onto the stationary phase, etc. The speed at which the components travel through the column is directly related to the number of absorption-elution cycles that occur. Therefore a balance between the solvation power of the mobile phase and the absorption power  of the stationary phase determines how fast each individual component travels through the  column.1,2 Think of a piece of wood floating down a creek. If there is a lot of grass growing in the stream,  the wood will get caught in the grass for awhile, then it will break loose and flow down the creek  a short distance, get caught in some more grass or rocks, break free again, and continue this  process until it has made its way down the creek. Aluminum cans will travel down the creek at  different rates than the wood based on the amount of time they are retained by the grass. If there  is no grass in the creek, the piece of wood and aluminum can will both reach the end of the creek  WRONG!!! From the data gathered it can also be observed that the polar dye mixture, fluorescein ascended quickly when the solvent 1:12:14 K2SO4: H2O:CH3CN was used. This is primarily because the nonpolar compounds stick to the stationary phase, while polar compounds separate and travel upwards with the solvent. From the TLC plates, it is indicated that different compounds in the mixture travel a t different rates; polar compounds travel quickly while lesspolar compounds travel more slowly. The stationary phase was the substrate alumina which is considered to be a polar substance since the surface consists of polar (OH) groups. The moving phase is the solvent system that, moves up the stationary alumina coated plate. All solvent systems will be considered non-polar relative to the silica adsorbent. Potential problems leading to yield loss- In between two sand layers some impurities were trapped and on top of alumina fluroscien dye stayed. The 95% ethanol and mixture of blue dye dripped through columns down the container and collection of this clear mixture ended when solvent was colourless. Then sodium hydroxide was used to wash out the fluorescien dye into a separate beaker which caused the purple impurities to move down the cotton. This might be due to the thin layers of sand used or excessive solvent. However, this can be prevented by lowering the time it may take the dye to come down the column by increasing the air pressure from above (Still et al., 1978). Potential improvements to the process or problems with the experiments However, this can be prevented by lowering the time it may take the dye to come down the column by increasing the air pressure from above 3. The two dyes methylene blue and sodium hydroxide were used to separate fluorescien dye with ethanol in second part, column chromatography. References (1) Naff, M.B., Naff, A.S. 1963. TLC on microscope slides: An organic chemistry experiment. J.Chem. Educ.40 (10). pp 534, 535. (2) Schmidt-Tarub, H.2005. Preparative chromatography of fine chemicals and pharmaceutical agents. Wiley-VCH Verlag GmbH Co. kGaA, Germany. Pp131 (3) Still, W.C., Kahn, M., Mitra, A., 1978. Rapid chromatographic technique for preparative separations with moderate resolution. The Journal of Organic Chemistry.  43  (14). pp 2923-2925. (4) Poole, C.F. 2003. The essence of chromatography. Elsevier, United State of America. Pp.337 (5) Heftman, E. 2004. Chromatography 6th edition fundamentals and applications of chromatography and related differential migration methods. Elsevier, Netherlands. Pp. 549. Questions What would happen if the level of the solvent in your TLC chamber was higher than the spots at the bottom of your TLC plate? If the level of the solvent in the TLC chamber was higher than the spots at the bottom of the TLC plate then the spots would dissolve away. If the level of the solvent in the TLC chamber is deeper than the baseline, then the solvent will dissolve the compounds instead of allowing them to ascend the thin layer by capillary action. If this were to occur, in the end you would not see the spots after the plate is developed. As a drawing exercise, provide the structures of the dyes used in this experiment.**Knowing what you saw in class about intermolecular interactions, circle the groups on each molecule that are liable to interact with the partially acidic, surface Alà ¢Ã¢â€š ¬Ã‚ OH and Sià ¢Ã¢â€š ¬Ã‚  OH groups on alumina or silica in neutral solvent. Fluorescein: Molecules that are liable to interact with the partially acidic, surface Al- OH and Si- OH Methylene Blue: One of the solvents used contained aqueous NaOH. This will generate Alà ¢Ã¢â€š ¬Ã‚ O- and Sià ¢Ã¢â€š ¬Ã‚ O- groups on alumina or silica, and these will be in competition with the solvent for interactions with the analyte. What will this solvent do to the mobility of the dyes? Although the experiment you performed used the most common chromatography techniques, there are many other types of chromatography. One technique is called ion exchange chromatography, especially useful in biochemical work. Briefly describe the principle behind ion exchange chromatography and what it can accomplish. Ion exchange chromatography is a separation technique based on charges. It is used to separate ions and other charged molecules. There are two types of ion exchange chromatography, cation exchange chromatography and anion exchange chromatography. In cation exchange chromatography positively charged molecules are attracted to a negatively charged solid support and in anion exchange chromatography, negatively charged molecules are attracted to a positively charged solid support 4. In ion exchange chromatography the mobile phase, usually water or an organic solvent, is of low conductivity, which helps in the binding of the molecules 4. As the compound is passed through, like charges repel and elute first and opposite charges attract and elute last. The strength of the interaction is determined by the number and location of the charges on the molecule and on the functional group.  By increasing the salt concentration the molecules with the weakest ionic interactions start to elute from the column first 4. This type of chromatography is essentially important in the separating and isolating carbohydrates. It is also important in separating small inorganic and organic ions 5.

Gender-Bending in Shes Come Undone :: Shes Come Undone Essays

Gender-Bending in She's Come Undone  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚   Is Wally Lamb, author of   She's Come Undone, "qualified" to write a first-person narrator in a female voice? After all, as a man, what does he know about women's issues? In this essay I will discuss the issue of "gender-bending" writers and discuss Mr. Lamb's use of such tool.    The term "gender-bender" usually refers to a pop singer or a follower of a pop cult "...who deliberately affects an androgynous appearance by wearing sexually ambiguous clothing, make-up, etc. (Ayto and Simpson 81)" While authors are not included in this specific definition, we must not overlook the possibility that writers can fall under the category of being a "gender-bender." Applying some of the same characteristics of the definition, I believe that an author can be a "gender-bender" by changing the voice of the writer in the novels. Wally Lamb would fall under this category, because as a male author, he is writing his main character in a female voice. The concept of "gender-bending" authors is not completely foreign to literature, while it may not be applied to the definition presented above. For example, in detective novels that are written by women, some of the characters take on different genders than their writers. In the following passage, taken from the essay "Gender (De)Mystified: Resistance and Recuperation in Hard-Boiled Female Detective Fiction," by Timothy Shuker-Haines and Martha M. Umphrey, discussion is made of detective author Sue Grafton's ability to write in the male persona. Kinsey Millhone's [a female character in the book F Is for Fugitive] persona is gendered substantially as masculine. A woman who has few friends and lives for her work, she is self-consciously, almost parodically male-defined, as, for example, when she describes her tendency to amuse herself with the abridged California Penal code and textbooks on auto theft rather than engaging in the teatime gossip of a Miss Marple. (Delamater and Prigozy 73) "Gender-bending" also refers to sex change operations. Such as the case with performance artist Kate Bornstein - a graduate of Brown University - who underwent such an operation thirteen years ago. In an article on the school's website, Ms. Bornstein discusses "gender-bending" and some of the issues she discusses can also apply to "gender-bending" in novels. The way I view gender is a way to express yourself. ...Gender is just a doorway, and so is sexuality, race and age.

Are Reason and Emotion Equally Necessary in Justifying Moral Decisions Essay

Emotion is a strong feeling, desires or passion. It is real and operative. The feeling is mostly caused by consequences of minds’ past conclusions and beliefs of the people. Also, it is sometimes incomprehensible because their ideas are not largely sub-conscious, but also inconsistent (Skysite). Men can accept ideas without knowing if it is right or wrong and this may lead to thought or feeling without even aware of what is really happening. The fact is not observed and accepted only in our minds. Furthermore, it is a reaction in one’s perception. It has no observation. What comes in our minds can either be true or false. Once a man acquires knowledge, it automatically keeps on the minds without even aware or no facts are observed. The process of learning, judging and implying are applied continuously. The reaction of the acquired knowledge is the emotion (Skysite). A man has a certain feeling or emotion is because of the earlier knowledge that the man acquires which is stored in his subconscious mind. It follows that the acquired ideas need support and ideas need to be validated for confirmation to make it valid or acceptable (Skysite). Reason is awareness. The data is studied, observed and organized. You are directly guided with an observed data. The organized and observed data is relevant and truth. The man is obliged to believe the fact (Skysite). Emotions are reactions of man’s ideas. He accepts ideas through mind and may think of ways of improving those ideas and think of reality itself. So, the process of reason is therefore should be identified by studying those ideas to be able to meet the reality which is the reason. Reason is to recognize the reality, or the real meaning of life, the people, the country and the world. Based on our own recognition of the world, we react through our emotions. It is generally believe to rely on passion follow reason. The reason is known as slave of passion. We follow our beliefs. Our reaction is based on our thinking because we believe on it (Machan). One example is Euthanasia. Euthanasia is the practice of having a medically-assisted death or mercy-killing. In some countries, it is illegal. It is a debatable subject among different moral quandaries related to it (Wikipedia). Euthanasia is conducted with certain criteria to consider. It is not simply killing the person automatically. It is done with consent. It can either be voluntary or involuntary which means with consent or without consent respectively (Wikipedia). If a man believes in the words of God or the story of the Bible which is known to be the Holy Book of some religion, the emotion of the man is unhappy or afraid because probably, he doesn’t agree to Euthanasia because in the Bible Euthanasia is not acceptable. Man is afraid of practicing Euthanasia because he believes in the Bible. If we think of a reason, the man believes in what the Bible says and believes everything will be alright if we believe in God’s words that are written in the Holy Book of the Christians. However, if a man is suffice with the whole study of Euthanasia and he believes in Euthanasia because if a man is dying and can’t live any longer, it is therefore get his consent to apply Euthanasia for a reason. To prevent him from feeling the pain longer, he believes that Euthanasia is said to apply. Euthanasia is accepted in the man’s mind which is generally leads to emotions, but the reality itself and the reason behind the process of Euthanasia is because the man is dying and he can’t live longer, it is better to cut his life earlier than feeling the pain longer. Because of the observed data which is the reason behind the practice of Euthanasia to man, the mercy-killing is acceptable to the man’s sub-consciousness. If a man is dying and can’t live any longer, the man accepts voluntary euthanasia rather than a financial burden to his family. In this regard, emotion followed by a reason. The emotion to consider is he feels bad because he knows that his family will bound to financial problems which is the reason for accepting euthanasia. Another example is the abortion. Some countries don’t agree with abortion because it is a murder. Any live person that you intentionally killed is known as murder. Some believe in abortion. It is applied and required for a certain reason. Probably, the mother is experiencing certain ailments or sickness that needs serious treatments like drinking medicines that are not good for the infant inside the womb, the child should be aborted because if not, the child will unluckily live an abnormal life because of his abnormal behavior. Unfortunately, if the child will be aborted, the mother will feel bad, but if the child will be aborted for a reason you will somehow feel less disappointed because you’ll know for a reason that the child will either become abnormal or die young. The reason behind the abortion of the child inside the womb is to save the child for sufferings for life. In the contrary, if we don’t agree in abortion because of our belief, our reason here is not to abort the child for the reason of the belief itself. For instance, the man recognizes that he doesn’t believe in abortion. The response of that belief is known to be our emotion. The reason now follows. Because the man doesn’t believe in abortion because of his faith, it is known to be the reason for not believing on it. The infant inside should be aborted and wait for his coming to the world of people. Further example is the divorce. Some countries, divorce is acceptable, but in some are not. This divorce really depends on our own belief. We all know that in the higher level of Christian church, divorce is not really acceptable to them because, they believe that if you are both blessed to be together for life, you should be together for good or worse. If a man believes, your emotions will be the response of what you think. For instance, your emotion is to love and respect the person you are with. The reason is to take care of the relationship for life. Emotions and reasons are perfect harmony which means that they are compatible with the opinion and action. People need both emotion and reason in order to make decision according to neuroscientists. It is really complicated when it comes to the reasoning, but the most important for me is how you apply it by means of your own beliefs. It is important to broaden up you knowledge to come up with the best part which is the decision making process. It is significant and important because with your decision, you will bring happiness and contentment in your life.

The Media s Influence On Female Adolescents - 1724 Words

â€Å" The media needs to take responsibility for the effect it has on our younger generation....why aren’t we regulating things like calling people fat†(Lawrence)? The actress Jennifer Lawrence expressed her opinion on what she believes, that the media is responsible for the damaging body image that has affected the younger generation. Considering this, recently there have been more studies and research on what has formed this ideal body.Also, the research conducted uncovered that the famous doll Barbie is one of the main reasons for the desire to have an unrealistic body. The negative body image in female adolescents has been affected by the influence of impossible body types in the media such as the doll â€Å"Barbie† and characters in popular†¦show more content†¦After this statistic was proven, various amounts of examinations were performed to discover the ideal body type in juveniles. The various investigations influenced a woman named Renee Ho bbs and her research team to create a website called â€Å"My Pop Studio†, where people online can create their own celebrity images based on physical characteristics. Soon enough, the results were revealed, and it proved that the majority of girls who went on â€Å"My Pop Studio† created themselves to look tall, very thin, and blonde (Heuback). These results infer that being tall, thin, and blonde is the ideal image young girls desire to have. In summary, the examinations that were managed proved that young girls are dissatisfied with their body, and would change their appearance if they had the chance. Also, traditional types of media such as magazines, TV shows, and commercials affect the perception of body image. Furthermore, a recent study revealed adolescent females who watch reality TV more than the average person start to care more about their appearance (â€Å"11 Facts†). After these examinations were proven, researchers started to investigate popu lar kid’s channels such as Disney Channel or Nickelodeon. A review analyzed 134 episodes of Nickelodeon and Disney Channel shows, uncovered girls between the age of 10 to 17 became underweight (Culp- Ressler). Also, Disney was criticized for allegedly slimming their iconic characters ; Minnie Mouse and Daisy Duck (Culp-Ressler). Popular