Gas Chromatography - What It Is and How It Works

Gas chromatography (GC) is an analytical technique used to separate and analyze samples that can be vaporized without thermal decomposition. Sometimes gas chromatography is known as gas-liquid partition chromatography (GLPC) or vapor-phase chromatography (VPC). Technically, GPLC is the most correct term, since the separation of components in this type of chromatography relies on differences in behavior between a flowing mobile gas phase and a stationary liquid phase. The instrument that performs gas chromatography is called a gas chromatograph. The resulting graph that shows the data is called a gas chromatogram. Uses of Gas Chromatography GC is used as one test to help identify components of a liquid mixture and determine their relative concentration. It may also be used to separate and purify components of a mixture. Additionally, gas chromatography can be used to determine vapor pressure, heat of solution, and activity coefficients. Industries often use it to monitor processes to test for contamination or ensure a process is going as planned. Chromatography can test blood alcohol, drug purity, food purity, and essential oil quality. GC may be used on either organic or inorganic analytes, but the sample must be volatile. Ideally, the components of a sample should have different boiling points. How Gas Chromatography Works First, a liquid sample is prepared. The sample is mixed with a solvent and is injected into the gas chromatograph. Typically the sample size is small -- in the microliters range. Although the sample starts out as a liquid, it is vaporized into the gas phase. An inert carrier gas is also flowing through the chromatograph. This gas shouldnt react with any components of the mixture. Common carrier gases include argon, helium, and sometimes hydrogen. The sample and carrier gas are heated and enter a long tube, which is typically coiled to keep the size of the chromatograph manageable. The tube may be open (called tubular or capillary) or filled with a divided inert support material (a packed column). The tube is long to allow for a better separation of components. At the end of the tube is the detector, which records the amount of sample hitting it. In some cases, the sample may be recovered at the end of the column, too. The signals from the detector are used to produce a graph, the chr omatogram, which shows the amount of sample reaching the detector on the y-axis and generally how quickly it reached the detector on the x-axis (depending on what exactly the detector detects). The chromatogram shows a series of peaks. The size of the peaks is directly proportional to the amount of each component, although it cant be used to quantify the number of molecules in a sample. Usually, the first peak is from the inert carrier gas and the next peak is the solvent used to make the sample. Subsequent peaks represent compounds in a mixture. In order to identify the peaks on a gas chromatogram, the graph needs to be compared to a chromatogram from a standard (known) mixture, to see where the peaks occur. At this point, you may be wondering why the components of the mixture separate while they are pushed along the tube. The inside of the tube is coated with a thin layer of liquid (the stationary phase). Gas or vapor in the interior of the tube (the vapor phase) moves along more quickly than molecules that interact with the liquid phase. Compounds that interact better with the gas phase tend to have lower boiling points (are volatile) and low molecular weights, while compounds that prefer the stationary phase tend to have higher boiling points or are heavier. Other factors that affect the rate at which a compound progresses down the column (called the elution time) include polarity and the temperature of the column. Because temperature is so important, it is usually controlled within tenths of a degree and is selected based on the boiling point of the mixture. Detectors Used for Gas Chromatography There are many different types of detectors that can be used to produce a chromatogram. In general, they may be categorized as non-selective, which means they respond to all compounds except the carrier gas, selective, which respond to a range of compounds with common properties, and specific, which respond only to a certain compound. Different detectors use particular support gases and have different degrees of sensitivity. Some common types of detectors include: Detector Support Gas Selectivity Detection Level Flame ionization (FID) hydrogen and air most organics 100 pg Thermal conductivity (TCD) reference universal 1 ng Electron capture (ECD) make up nitriles, nitrites, halides, organometallics, peroxides, anhydrides 50 fg Photo-ionization (PID) make up aromatics, aliphatics, esters, aldehydes, ketones, amines, heterocyclics, some organometallics 2 pg When the support gas is called make up gas, it means gas is used to minimize band broadening. For FID, for example, nitrogen gas (N2) is often used. The user manual that accompanies a gas chromatograph outlines the gases that can be used in it and other details. Sources Pavia, Donald L., Gary M. Lampman, George S. Kritz, Randall G. Engel (2006).  Introduction to Organic Laboratory Techniques (4th Ed.). Thomson Brooks/Cole. pp.  797–817.Grob, Robert L.; Barry, Eugene F. (2004).  Modern Practice of Gas Chromatography (4th Ed.). John Wiley Sons.Harris, Daniel C. (1999). 24. Gas Chromatography. Quantitative chemical analysis  (Fifth ed.). W. H. Freeman and Company. pp. 675–712. ISBN 0-7167-2881-8.Higson, S. (2004). Analytical Chemistry. Oxford University Press. ISBN 978-0-19-850289-0

Video Game Violence Video Games - 892 Words

Video Game Violence On December 14, 2012, a twenty year old boy named Adam Lanza shot twenty children and six staff at Sandy Hook Elementary School in Newtown, Connecticut. Before arriving to the school, he shot his mother then committed suicide after the shooting. The reports say that he was influenced to shooting others by the video game â€Å"Call of Duty†. Video game violence is defined as a behavior including physical violence intended to hurt, damage, or kill someone or something impacted by video games. Video games can increase the aggressiveness of kids and young adults. According to technology fox news, video games stimulate aggressive thoughts. In the study, children ages of eight to seventeen who constantly play video games exhibit a more aggressive behavior such as pushing, hitting in comparison to three years before playing video games. In the meantime, the individuals who diminished the measure of time they spent playing fierce video games saw an abatement in fo rceful conduct, the specialists say. The explanation behind the increment in forceful conduct was the youngsters who play a great deal of brutal video games had an increment in forceful considerations: for example, they will probably decipher an uncertain demonstration, similar to somebody catching them, as unfriendly, said study analyst Craig Anderson, a therapist and teacher at Iowa State University. They were additionally more prone to see forceful conduct as a proper approach to react to incitement,Show MoreRelatedVideo Game Violence : Violent Video Games1626 Words   |  7 PagesDavis English III 27 March 2015 Video Game Violence Violent video games have been being created since the first console. Yet only recently have we been blaming them for aggression in the player. We as humans have a tendency to blame our violent behavior on other things rather thin ourselves. Now aggression is being defined in many ways in this situation but mainly people point to the anger that’s brought out in the real world after the game or maybe it’s the gamers’ tendency to haveRead MoreVideo Games : Video Game Violence Essay1693 Words   |  7 PagesVideo Game Violence Blood and gore, intense violence, strong sexual content, use of drugs. These are just a few of the phrases that the Entertainment Software Rating Board (ESRB) uses to describe the content of several games. The future of entertainment revolves around technology. Along with the evolvement of technology, video games are also changing. More ways of playing violent video games are created each year, but most of us have this question in mind; do violent video games influence peopleRead MoreVideo Games : Video Game Violence1502 Words   |  7 Pages2013 Video Game Violence The evolution of video games has taken a drastic change since the 1970’s when video games were first introduced. Since then every decade video games have become more violent in nature with strong language and realistic to suit society today. Craig Anderson states that with more violence in video games they would sell better than games with less violence (Anderson, Gentile, and Beckley pg.5). Violent video games really became popular when the first person shooter games wereRead MoreVideo Game Violence And Violent Video Games2382 Words   |  10 PagesAbstract The issue of video game violence seems to be a hot topic right now after several shootings have occurred and made a connection to the shooters being video gamers. In looking at past research it is apparent that there seems to large amounts of research that contradict one work to another. Although I would have been interested in conducting a poll of the publics opinion regarding the use of violent video games and their connection to mass shootings I was not able to conduct the researchRead MoreVideo Games and Violence1011 Words   |  4 Pagesare probably millions and billions of video games sold every year to people. Some people seem to believe that violence correlates directly with video games. Video games are something that is usually a big interest in people at the ages of 13 to 19 years old. Video games usually start off as a little fun and then turn into a major hobby for some people. Emotions change based on whatever happens while a person is engaging in these games most of t he time. These games are another way to observe how peopleRead MoreVideo Games Violence664 Words   |  3 PagesUNV - 104 August 11, 2013 Video Games and Violence Video games and violence have different effects on children according to the type of video games that is being watched It is important to understand the world of video games. All video games do not prevent violence in children. Parents should take into consideration in monitoring their child while choosing video games. Depending on the video game that is chosen, does not mean the child will result in violent behavior later on in lifeRead MoreVideo Games and Violence1981 Words   |  8 Pagesconcerned about violent video games due to the increased reality in the games. However, society may not realize how children and teens are affected by these games. In modern times, children and young adults are affected by violent games in a negative way by causing changes in their behavior. The average American child watches 28 hours of television a week and by the age of eighteen will have seen 16,000 murders and 200,000 violent acts (Gallagher). People who defend violent games like to po int out thatRead MoreThe Violence Of Video Games971 Words   |  4 PagesMost kids today play video games to entertain themselves and it’s their hobby. Today kids and even young adults play games like Grand Theft Auto V (GTA V), Call of Duty, and Fallout 4. All three of these games were one of the top games of their respective year of release. What do they all have in common? They depict violence in a way that its becoming more realistic every year they’re sequels are released. But what’s up with people blaming video games for mass shootings and other heinousRead MoreVideo Games and Violence942 Words   |  4 Pages Video Games and Violence Awe entering in more advanced society of technology, video games has become a popular source of entertainment among us. Almost all of us has rented or owned a video game and we have spent hours playing it. As we all know, video games have become the second most popular form of entertainment after television; the source of entertainment is proven to be violent. Excessive playing of video games has a huge impact on our life as well asRead MoreDo Video Games Contribute For Video Game Violence?1170 Words   |  5 Pages Do video games contribute to video game violence? I will discuss why video games do not contribute to youth violence, what types of warnings are given by video game companies, and what flaws exist in studies that suggest a correlation between violence and gaming. As the sales of video games have risen in recent years, some groups claim that violence in these games has caused violent behaviors among young players. However, this argument bears little factual evidence supporting such a connection

Ottoman and Safavid Free Essays

In the late Islamic period (16th -18th), perhaps even more so than in preceding periods, art was an instrument of dynastic expression in this great age of empires. Spurred by royal patronage, the arts flourished under the Ottomans and Safavids. Ottoman art was a vibrant synthesis of Turkish and Persian-Islamic, Byzantine, and Mediterranean culture and styles through conquest, through direct invitation of artisans, or through the migration of peoples. We will write a custom essay sample on Ottoman and Safavid or any similar topic only for you Order Now The Ottoman Turks were renowned for their architecture, as well as for their traditions of calligraphy and miniature painting. They were also renowned for their decorative arts including carpet weaving, jewelry making, paper marbling, and their characteristic Iznik ware ceramics. The Ottomans promoted themselves as the defenders of Islam, and this explains why their public art includes a rich variety of ornamental designs but no human figures. Plant- and flower-based patterns were the most common. Observing Iznik ceramics, a superficial abstraction is dominant in the naturalistic plant designs. Besides, around 16th century Ottoman Miniature Art reached its peak. The Miniatures and illuminated manuscripts were created largely for the emperors, with their focus mostly on the important and powerful figures in their retinues. A unique feature of Ottoman Miniature was that it depicted the actual events realistically, while also keeping the abstract formal expressive touch of the traditional Islamic Art. The Safavid style developed in Iran from 1500, when the country was re-united under the dynasty of this name. Unlike their Ottoman neighbors, the Safavids had no qualms about depicting human beings in all forms of art. These figures became an unusually prominent feature of the Safavid style. Depictions of elegant young men and women, often shown in outdoor settings, adorned many objects, from clothing to the bindings of manuscripts. One of the most renowned manuscripts from the period is a now-dispersed copy of the Shahnama epic. Also textiles and carpets were manufactured of luxury materials as furnishings for the court. The most famous is a pair known as the Ardabil Carpets, created in 1539-1540. The carpets were nearly identical, perfectly symmetrical and enormous. Every inch of space was filled with flowers, scrolling vines, and medallions. Although the central medallion and the repeating patterns throughout the carpet is similar to Ottoman but the Ardabil carpets have A wide range of colors than Ottoman’s which is heavily dependent on reds and blues. How to cite Ottoman and Safavid, Papers

Project Management for Opening Street Food †MyAssignmenthelp.com

Question: Discuss about the Project Management for Opening Street Food. Answer: Sydney Metro Station in NSW, a good place for street food opening Sydney Metro Station is one of the most attractive places for the customers to come and avail food from the food trucks and vans (Sainsbury, Colagiuri Magnusson, 2107). Customers visit the metro station as it is a daily part of their journeys. Street food keeps customer connected with the vendor. Considering the Sydney metro station as one of the busiest station in North South Whales in Australia, it attracts most of the customers for availing food from the street trucks and street vans. Food vans and food tucks are built to bring fashion and food together in one campus. There are mainly two types of mobile food vending- Food vans and food trucks. Food vans are those which sell food that are not harmful and include practices that involve low risks. Whereas Food trucks are those mobile foods vending that takes risks (Zhao Li, 2017). Food that are cooked in the place itself or the food in which temperature are to be maintained are considered as hazardous food. Food plays an important role in functioning of the cities. The people are religiously and socially connected to food. Sydney metro station, an important plays for daily visit for the citizens of NSW helps the food vendor outside the metro station to establish their business in selling of food. As an opening business, discounts on foods are given to the availing customers. The environment that is built outside the metro station of Sydney creates an impact on interaction of people with food making it a good place for a startup business to sell their food. Permissions needed for local vendors The local street vendor needs permission from the local owner or the council they are selling food at. The permission and the amount of tax that they have to give to the government differ in different places. The approval policies of the local area are given to the mobile food vendors in Sydney. There are particular laws for handling of safe food and the practices that require in preparation of food (Hal et al., 2016). The conditions that are needed for trading on the street that includes the total number of hours for selling of food and the exact location of the area where to sell the food and the occurrence of other businesses. The procedures for availing permission for different types of food seller are different. Policies are different in every area including the number of hours and the type of food that they are selling. The different areas in Sydney where different policies are based are as follows- Policies for food truck Policies of food van Approval policy of mobile food vending Management operation plan The policies for mobile food vending are that any of the registered vehicles that are used in the area of the metro station are either towed down council or is self driven (Ahmed et al., 2014). The vehicles do not include bikes or cars or not any fixed shop. These types of vehicles are not given registration. On side food preparation is done by vehicles vending mobile food such as tacos and burgers and food that needs one step preparation such as coffee, popcorns and any type of food that are pre packed. Under vehicles of mobile food vending, there are two categories- Food vans includes Category 1 and Food trucks include Category 2. Food vans include foods that are not hazardous such as preparation of coffee or ice-creams. A food truck involves hazardous food such as making of food and keeping the temperature right for the food that needs the temperature. The vendors of mobile food vehicle should ensure that they have the permission for using the road owned by the Council before starting their business. The vendors should satisfy the requirements of legislation of the metro area of Sydney and the Policy. References Sainsbury, E., Colagiuri, S., Magnusson, R. (2017). An audit of food and beverage advertising on the Sydney metropolitan train network: regulation and policy implications.BMC public health,17(1), 490. Zhao, P., Li, S. (2017). Bicycle-metro integration in a growing city: The determinants of cycling as a transfer mode in metro station areas in Beijing.Transportation research part A: policy and practice,99, 46-60. van Hal, S. J., Espedido, B. A., Coombs, G. W., Howden, B. P., Korman, T. M., Nimmo, G. R., ... Jensen, S. O. (2016). Polyclonal emergence of vanA vancomycin-resistant Enterococcus faecium in Australia.Journal of Antimicrobial Chemotherapy,72(4), 998-1001. Ahmed, R. M., Irish, M., Kam, J., van Keizerswaard, J., Bartley, L., Samaras, K., ... Piguet, O. (2014). Quantifying the eating abnormalities in frontotemporal dementia.JAMA neurology,71(12), 1540-1546.