Inductively Coupled Plasma †Atomic Emission Spectroscopy Essay Example for Free

Inductively Coupled Plasma – Atomic Emission Spectroscopy Essay The aim of this practical was to use an ICP-OES to perform a multi-elemental analysis of different types of tea. The elements that were analysed in the tea were copper, iron, manganese and magnesium. The sample is introduced into the plasma as an aerosol. Argon gas flows through three concentric quartz tubes in the plasma torch. This argon gas transports the sample from the nebulizer, acts as a cooling gas and is also a source of electrons and ions for the plasma [1]. A magnetic field is created around the plasma torch. The ionisation process is started by the ignition of the argon gas from a spark produced by a tesla coil [1]. During this process the plasma reaches a very high temperature and the sample is atomised. The atoms are then excited to a higher state. Since this is an emission analysis, the analysis is performed as the atoms emit energy and return to a lower energy state or their ground state. A spectrometer or monochromator is used to select the wavelength that is being analysed. The multi-element detector then gives us a readout that can be understand for each element that is analysed Explain the benefits and limitations of plasma over a conventional flame used for FES with photometry and AAS. The benefits of using plasma are that the chemical interferences are decreased due to the high temperatures that the plasma reaches and refractory elements can also undergo excitation. There are also many wavelength for different that can be chosen for analysis so you don’t have two elements that have wavelengths that are close to each other as this would interfere with the analysis. A limitation is that spectral overlap can occur and the preparation of the samples is a very long process compared to that of the flame spectrometry Data Show the calculations for you multi-element standard. Instrument: Perkin Elmer OES (optima 5300 DV) The preparation of multi-element standard 1000ppm solutions of (Cu), (Fe),(Mg) and (Mn ) were given. A working standard solution containing the entire four elements was prepared in the following way; 1 ml, 10 ml and 5 ml of Fe, Mg, and Mn were respectively added in one 100 ml volumetric flask. A solution of Cu was prepared separately (intermediate solution) by placing 1 ml of the 1000ppm Cu solution in a 100 ml volumetric flask and made up to the mark with distilled water, the resulting concentration was 10ppm. The formula that was used to calculate the volume of the 1000ppm Cu solution needed to prepare 10ppm solution in a 100 ml volumetric flask is; C1V1 = C2V2 †¦Ã¢â‚¬ ¦ equation 1 Where C1 is the initial concentration C2 is the final concentration V1 is the volume of the initial concentration V2 is the total volume of the initial concentration and the solvent The volume of the barium required was calculated as follows C1V1 = C2V2 1000ppm x V1 = 1ppm x 100ml V1 = 10 ppm x 100 ml 1000 ppm = 1 ml Then 1 ml of the 10 ppm Cu solution was placed in the 100 ml volumetric flask that contained the other three elements, and made up to the mark with distilled water, this was the working standard solution. Using equation 1 it is found that the concentrations of the elements in the working standard solution are as follows. Explain why the type of sample preparation carried out was necessary. The Acid digestion was suitable because a complete transfer of analyte into the solution in order for the determination step to be introduced in liquid form is highly desirable and this method completely transfers the analyte into solution. This thus means that the digested sample is a complete solution of the analyte and has a complete decomposition of the matrix however with minimal loss or contaminated of the analyte Explain what matrix matching is and what problems may arise if this is not carried out. Matrix matching involves preparing solutions in which the major chemical compositions of the standards, blanks and samples are made identical thereby cancelling out the effect of the sample matrix on the analysis results. While matrix matching involves matching the solvents, it also involves matching the concentrations of acids and other major solutes. In case where the standard and sample matrices are quite different or cannot be matched and interference occurs as a result, internal standards can be used. Comment on the correlation coefficient of your calibration graphs. The correlation coefficient measures the strength in the linear relationship between two variables. A correlation coefficient of 1 would mean a very strong linear relationship between two variables, which means the points form a perfect straight line. The correlation coefficients for the calibration graphs were very good. The calibration graphs for copper, iron, magnesium, and manganese gave correlation coefficients of 0.991539, 0.991005, 0.999874, and 0.999952 respectively. This shows that the samples were prepared very well and that there is a strong linear relationship between the emission and the concentrations of the elements. Compare the different elements in the different types of tea. Which tea would you recommend and why? The tea that seems to be most essential for human consumption is the green tea owing to the high content of each and every element present in it. It has high concentration of manganese which is a vital substance in the body as it is an enzyme activator; it keeps bones strong and healthy, and also maintains the health of our nerves. References 1. Dr L Pillay, Chem 340, Instrumental Analysis, ICP-OES notes 2. http:// www.whfoods.com/genpage.php?tname=nutrint dbod=77(accessed 16/04/2013) 3. http://www.chemplex.com/petrochemical/multielementMetal.aspx(accessed 16/04/2013)

Business Ethics Essay -- Papers

Business Ethics Business ethics is a diverse field that cannot be defined with a single definition. This area addresses numerous issues, problems, and dilemmas within the management of businesses. Does this through numerous perspectives and methods. Of course, in order to present the complexities of business ethics, we must explore the types of issues that business professionals are continuously confronted with. To understand one must know the definition of corporate ethics as well as knowing what the ethics of responsibility are. After defining what ethics are, we then need to see how these are played out within management. This will show the decline and fall of business ethics over time and how whistle blowing has played its part. Business ethics not only portray humans, but also how businesses treat the environment. The majority of European and U.S. CEO's and higher ranking managers define corporate ethics as a subject that is to be dealt with at three levels; (1) the corporate mission, (2) constituency relations, and (3) policies and practices. The corporate mission is the most easily recognized and widely applicable category. Executives say that the enterprise in which they are engaged in, and the products or services that they market, should serve an essentially ethical purpose and that a companies first ethical responsibilities are defined by the nature of their objectives (Madsen and Shafritz, 1990). Managers also speak of constituency relations when formulating their company's ethical standards. This usually requires the creation of statements of corporate responsibilities for each individual company. Most of the codes describe the company's commitment toward certain groups rather than... ...from all. Business ethics are complicated, multi-issue problems that are ever changing in our fast-paced world. It is a very complex issue entailing many things from corporate ethics to the ethics of responsibility. Whistle blowing is one result of declining corporate ethics and the decline of ethics has declining corporate ethics and the decline of ethics has led to negative impact on the environment. These complex issues must be addressed or an ever increasing basis in the future. REFERENCES Madsen, Peter. Shafritz, Jay, M. (1990). Essentials of Business Ethics. New York, NY: Author. The Wall Street Journal. (1989). Dow Jones and Company Inc. Magnet, Myron. (1988). The Decline and Fall of Business Ethics. Fortune: Time Inc. Benson, G. C. S. (1982). Business Ethics in America. Lexington MA: D.C. Heath and Company.

Human motivation Essay

In studying human motivation, one of the key concepts includes the notion of needs and drives which may be the spring boards of actions or behavior. In line with these, efforts were exerted to look into the possible link of control of one’s impulsivity and certain critical behaviors that may affect any individual undertaking, his normal development through life’s stages, and possibilities of disorders or problems with the person’s overall functioning (Baumeister et al. ; Mischel et al, 1989). There is an offshoot of these studies (Hom and Knight, 1996) which highlights delayed gratification and the advantages of individuals who understand either by training or by serendipitous circumstances the rationality of their choices. Delaying the gratification of certain desires at the present entails certain calculations of the possible effects of these options at a certain point in the future. It involves the understanding of â€Å"profiting† from what the self is deprived of at the present to secure a better output or outcome in the near future. According to studies, a person who has been reared to control many of the urges to satisfy immediate needs or wants, may reap immense benefits in terms of significant life choices; choices that spell longevity (living physically healthy), prospect of better income, and healthier relationships. There are various reasons offered why this is so, but more often, the results of these choices to delay gratification oftentimes reveal the benefits; otherwise, when immediate satisfaction is allowed in most cases, the awareness of detrimental effects becomes a stark reality. The issue pertains to persistence, control, character development, cementing of values that enables a person to become an asset rather than become a liability to one’s community. Implications of a person’s ability to delay his or her immediate gratification (because of the prospect of more favorable results later) include responsibility over his/her actions and decisions and thereby increasing awareness of consequences including those which not only impact his/her own survival but also the effects of his/her decisions and actions to the people around (Mischel et al, 1989). References: 1. Baumeister, Roy, Brandon Schmeichel,Kathleen Vohs. Self-regulation and the Executive function: The Self as controlling agent. Accessed October 13, 2008 http://72. 14. 235. 104/search? q=cache:qpSCcMZijV0J:www. csom. umn. edu/assets/71708. pdf+Explain+the+value+and+importance+of+delayed+gratification+in+human+motivation&hl=tl&ct=clnk&cd=46&gl=ph 2. Hom, Harry, Jr. Heather Knight, 1996. Delay of Gratification: Mothers’ Predictions about Four Attentional Techniques; Journal of Genetic Psychology, Vol. 157. 3. Mischel, W. , Shoda, Y. & Rodriguez, M. L. 1989. Delay of gratification in children. Science, 244, 933-938.

An Evolution of the Human Brain

Human organs, much like the human heart, have changed and evolved over the history of time. The human brain is no exception to this natural phenomena. Based on Charles Darwins idea of Natural Selection, species that had larger brains capable of complex functioning seemed to be a favorable adaptation. The ability to take in and understand new situations proved invaluable to the survival of Homo sapiens. Some scientists believe that as the environment on Earth evolved, humans did as well. The ability to survive these environmental changes was directly due to the size and function of the brain to process the information and act upon it. Early Human Ancestors During the reign of the Ardipithecus Group of human ancestors, brains were very similar in size and function to those of a chimpanzee. Since the human ancestors of that time (about 6 million to 2 million years ago) were more ape-like than human, the brains needed to still function like that of a primate. Even though these ancestors tended to walk upright for at least part of the time, they did still climb and live in the trees, which requires a different set of skills and adaptations than that of modern humans. The smaller size of the brain at this stage in human evolution was adequate for survival. Toward the end of this time period, the human ancestors began figuring out how to make very primitive tools. This allowed them to begin hunting larger animals and increase their protein intake. This crucial step was necessary for brain evolution since the modern human brain requires a constant source of energy to keep functioning at the rate it does. 2 million to 800,000 Years Ago Species of this time period began moving to different places across the Earth. As they moved, they encountered new environments and climates. In order to process and adapt to these climates, their brains began to get bigger and perform more complex tasks. Now that the first of the human ancestors had begun to spread out, there was more food and room for each species. This led to an increase in both body size and brain size of the individuals. Human ancestors of this time period, like the Australopithecus Group and the Paranthropus Group, became even more proficient in tool making and got a command of fire to help keep warm and cook food. An increase in brain size and function required a more diverse diet for these species and with these advances, it was possible. 800,000 to 200,000 Years Ago Over these years in the history of the Earth, there was a large climatic shift. This caused the human brain to evolve at a relatively rapid pace. Species that could not adapt to the shifting temperatures and environments quickly went extinct. Eventually, only Homo sapiens from the Homo Group remained. The size and complexity of the human brain allowed individuals to develop more than just primitive communication systems. This allowed them to work together to adapt and stay alive. Species whose brains were not large or complex enough went extinct. The different parts of the brain, since it was now large enough to not only accommodate instincts necessary for survival but also more complex thoughts and feelings, were able to differentiate and specialize in various tasks. Parts of the brain were designated for feelings and emotion while others stayed with the task of survival and autonomous life functions. The differentiation of the parts of the brain allowed humans to create and understand languages to communicate more effectively with others.