Investigation Into The Use Of Short Column Reversed Phase Lc In The Determination Of Log P Values 2.

1566 words - 6 pages

AimTo illustrate how gas chromatography (GC) may be used for the identification and quantification of individual constituents of a complex natural product.IntroductionGas chromatography (GC) separates mixtures into their individual components and is particularly useful for volatile and semi-volatile compounds. GC is used in the analysis of a wide variety of samples, including paints, polymer additives, solvents, hydrocarbons, pesticides, and drugs. Samples are introduced to the stationary phase of the capillary column as vapours or dissolved in solution. As the column is heated, an inert gas acting as the mobile phase is passed through the column. Each compound in the sample is carried through the column at a different rate, separating the sample into its individual components. Each component is detected as it emerges from the column by a flame ionization detector. The "retention time" spent in the column for each component is used for identification and the intensity of the signal for each component can be used to quantify the compound of interest. When reference standards can be analyzed under identical conditions, GC profiles can also be used as fingerprints of complex mixtures.TheoryThe GC consists of an injection block, a column, and a detector. An inert gas flows through the system. The injection chamber is a heated cavity which serves to volatilize the compounds. The sample is injected by syringe into this chamber through a port. Once inside, the sample becomes vaporized and is carried out of the chamber and onto the column by the carrier gas.The column is an integral part of the GC system. On the outside, all you see is a long stainless steel tube, which is coiled. Inside the column is the important component: the stationary phase composed of the high-boiling liquid. The liquid is usually impregnated on a high surface area solid support like diatomaceous earth, crushed firebrick, or alumina. The liquid can be applied in various concentrations: the more liquid, the more sites it has to interact with the compounds.The carrier gas is an inert gas, helium. The flow rate of the gas influences how fast a compound will travel through the column; the faster the flow rate, the lower the retention time.RecordersTwo devices are used to record the GC traces/areas under peaks:-integrating recorders-computer programEach type of device records the messages sent to them by the detector as peaks, calculates the retention time, and calculates the area under each peak; all of this information is included in the printout. For similar compounds, the area under a GC peak is roughly proportional to the amount of compound injected.Retention Time (RT)The retention time, RT, is the time it takes for a compound to travel from the injection port to the detector. The retention time is measured by the recorder as the time between the moment you press start and the time the detector sees a peak. If you do not press start at the same time you inject your sample, the RT...

Find Another Essay On Investigation into the Use of Short-Column Reversed-Phase LC in the Determination of log P Values 2.

An investigation into the use of cooperative Learning Strategies to foster positive social behaviour and satisfactory academic performance in Physical Education among a group of grade nine students.-...

618 words - 2 pages gradually developed into a culture that emphasizes individualism- a " me, myself and I' phenomena. Many people tend to be selfish and do not have a sense of solidarity or unity or cohesiveness. Some people refuse to cooperate with others and the continuous upsurge of political tribalism has added significantly to this problem. Lack of cooperation is evident in both major political parties, each sticking to its own agenda- caring not who gets hurt in

The Use Of Setting In A & P

733 words - 3 pages The setting of 'A & P'; is quite usual for a regular grocery store on a weekday. The town is north of Boston, five miles from the beach. Since the store is right in the middle of town, banks and churches and the newspaper store can been seen from the front doors. The day is Thursday, so there is not very much business. Outside, the sun can be seen on the pavement. The main character, Sammy, is almost nineteen years old and his coworker

The Use of Forensic Evidence in Investigation

3195 words - 13 pages Nearly anyone you ask would be familiar with the television show CSI. The crime lab is colorful and high-tech with all of the fun toys and machines that analysts use to test the ever abundant amount of forensic evidence from every crime scene. It makes for an exciting drama that you cannot help but get immersed in—it also gives us a false illusion, however, creating what has been dubbed as the “CSI effect” (Baskin, 2011). This effect describes

Descent into Postpartum Psychosis; This is a nine page research essay on the short story "The Yellow Wallpaper" We had to do an analysis on the story and use third person

2863 words - 11 pages treated for postpartum depression correctly. This short story is written in an era when little is known about postpartum depression, so these practices are considered beneficial. Often times what is intended to help can hinder. Positive intentions do not always bring about desirable effects on a patient. After having the baby, the woman is forced into an abandoned dull room in an attempt to have herself freed of her ailment. The narrator's husband

An Investigation Into The Effect Of Enzyme

2633 words - 11 pages visit http://www.iizukakei.com for free bogusmail.fake mail and book reviews and more! An Investigation Into The Effect Of Enzyme Concentration On The Rate Of Catalase Activity Equation: 2H2O 2 2H2O + O 2 Catalase is used to catalyse this reaction as hydrogen peroxide takes too long to decompose on its own. The source of catalase which I will be using will be from potato.Hypothesis: I believe that as the concentration of enzyme is increased, the

Compare and Contrast the UC and the LC in “The Hound of the Baskervilles”

973 words - 4 pages “The Hound of the Baskervilles” demonstrated the differences between the upper class and the lower class and even between those people who were in the same class as each others at the end of the 19th century in England. Beside those differences, there were also some similarities between the two classes. In this essay, I will analyse how they are alike and different in some main aspects such as the belief in the curse, the relationship to the

An Investigation into the Enthalpies of the Combustion of Alcohols

5145 words - 21 pages An Investigation into the Enthalpies of the Combustion of Alcohols ================================================================== Planning My aim for this experiment is to see the energy produced from different alcohols. This investigation involves burning alcohol in the air. ‘GCSE Chemistry’ by B.Earl and L.D.R Wilford says that "alcohols form, another homologous series, with the general formula Cn H2n+1OH ". The alcohol reacts

the theory of determination

2497 words - 10 pages when waves would crash into her board. Her father created a custom made board that had a handle for her to hold on to while diving with her board under the waves until she was able to compete at professional level with a short boards (“Bethany Hamilton-The Real Soul Surfer SUP Surfing & Boarding”, n.d.). These types of parents are not the ones that make the excuses for the students it is the community and educators that call the parents in

Short story summary of "The A&P" by John Updike

651 words - 3 pages "The A&P"In the short story, " The A&P," by John Updike, the author seeks to make his point using an unlikely setting and scenario. Using a supermarket as a metaphor for a society, Updike illustrates how breaking the norms of society evokes fear and brings about intolerance in people. When a society is accustomed to only one way of doing things it will not be accept anything different. Members of a society fear change, and only behavior

Analysis of the short story "A&P" by Updike

766 words - 3 pages "A&P" by John Updike is a story of an important event that matures and gives knowledge to Sammy, a young grocery store clerk. The story begins one summer day as three girls wearing bathing suits enter the store. Sammy fantasizes about the girls' bodies and appearances. Then when the girls come up to the Sammy's cashier to check out, the store manager, Lengel sees them and scolds them for dressing inappropriately in a public store. This

An investigation into the presentation of food science in a variety of non-fiction texts

2201 words - 9 pages text compared to the images this is because the pages appear to be split between images and text. This is because the desired audience hasn’t found a strong interest in food science. So the designer need to produce an article that is at a desirable amount of complexity whilst avoiding the use of too much profundity in the topic, which would ensue in the audience getting off task whilst at the other end of the spectrum, if the text was short the

Similar Essays

Nixon’s Use Of Executive Privilege To Prevent Investigation Into The Watergate Scandal

724 words - 3 pages irrevocably change America’s future by doing something that every president had done before him, he would use executive privilege to block the investigation into the White House’s role into the Watergate break-in. By invoking executive privilege, Richard Nixon proved his guilt and permanently changed how Americans viewed the president’s use of executive privilege. Of course, this was not the first time executive privilege had been invoked. In

An Investigation Into The Use Of Cooperative Learning Strategies To Foster Positive Social Behaviour And Satisfactory Academic Performance In Physical Education Among A Group Of Grade Nine Students. ...

756 words - 3 pages Purpose of The Study Purpose of The Study This study seeks to find out what environmental factors will foster or hinder the effective use of the cooperative learning strategy in promoting positive social behaviour. This research also seeks to find out to what extent students display positive social behaviour when engaged in cooperative learning and to what extent will the use of such strategy result in satisfactory academic

An Investigation Into The Use Of Cooperative Learning Strategies To Foster Positive Social Behaviour And Satisfactory Academic Performance In Physical Education Among A Group Of Grade Nine Students. ...

1215 words - 5 pages , possibly verbally or physically. These behaviour must be discouraged through the effective use of cooperative learning that seeks to encourage students to work together in unison and eliminate undesirable social behaviours. Attitudes may be formed or altered through the process of associative learning (Staats and Staats 1958). Our responsiveness to other human beings is perhaps the most obvious aspects of human experience. Learning together

An Investigation Into The Use Of Cooperative Learning Strategies To Foster Positive Social Behaviour And Satisfactory Academic Performance In Physical Education Among A Group Of Grade Nine Students. ...

1215 words - 5 pages , possibly verbally or physically. These behaviour must be discouraged through the effective use of cooperative learning that seeks to encourage students to work together in unison and eliminate undesirable social behaviours. Attitudes may be formed or altered through the process of associative learning (Staats and Staats 1958). Our responsiveness to other human beings is perhaps the most obvious aspects of human experience. Learning together