Gas Chromatography Mass Spectrometry Advantages and Disadvantages

Gas Chromatography Mass Spectrometry (GC-MS) combine two powerful techniques in order to provide the identification of compounds that have low detection limits and potential required for quantitative analysis. Gas Chromatography Mass Spectrometry analyses works on liquids, solid and gaseous samples but are primarily restricted to semi volatile and volatile compounds.

Under Gas Chromatography, a sample is carried and volatilized and carried by the inter gases through a coated glass Capillary Column. The stationary phase is joined to the interior of the column and the amount of time it takes a specific compound of an element to pass through this column on to a detector is called its “Retention Time”. These measurements are used for identification purpose when compared to references.

Under usual Mass Spectrometry or MS step under the Gas Chromatography Mass Spectrometry, the compounds leaving the GC columns are fragmented by the electron impact. These charged fragments are detected gradually and the subsequent spectrum obtained is used to identify the molecules. Fragmentation patterns are reproducible and thus, can be used to create quantitative measurements.

Gas Chromatography Mass Spectrometry analysis is performed on gases, solids and liquids. For gases and liquids, the samples are usually injected directly into the Gas Chromatogram. For the solid elements, the analysis is carried our through outgrassing or desorption, solvent extraction or pyrolysis. Desorption experiment is performed under the flow of helium gas at controlled temperature ranging between 40 to 300 degree Celsius. The analytes are then collected on a Cryogenic trap during desorption process. The sample chamber is a 1.25″x4″ cylinder.

Pyrolysis is yet another sampling technique used for the analysis of materials that are impossible to be directly injected into Gas Chromatography Mass Spectrometry. Under this process, heat is directly applied to the sample that results in breaking down of the molecules in a reproducible way. These smaller molecules are then introduced in the Gas Chromatogram and analyzed by the GC-MS. By this method, probe temperatures of up to 1400ÂșC can be used.

Several other sampling methods and sample preparation are available such as static headspace analysis, derivatization, purge and trap, Solid Phase Microextraction etc. having applications based on species of interests and sample types.

Strengths

  • Identification of organic components through separating complex mixtures
  • Quantitative analysis
  • Trace determination of organic contamination (low to mid-ppb level for liquid matrices and low nanogram level for solid matrices?

Ideal Uses

  • Identifying and quantifying volatile organic compounds in mixtures
  • Outgassing studies
  • Testing for residual solvents
  • Evaluating contaminants on semiconductor wafers or other technology products (thermal desorption)
  • Identifying trace impurities in liquids or gases

Limitations of Gas Chromatography Mass Spectrometry

  • Non-volatile matrices (wafers, metal parts oil, etc.) require additional prep (extraction, outgassing, etc.)
  • Evaluating extracts from plastics
  • Target compounds must either be volatile or capable of derivatization
  • Atmospheric gases are challenging (CO2, N2, O2, Ar, CO, H2O)

Advantages

GC MS has long been considered to be the Gold Standard for all sorts of analytical laboratories. It is a strong analytical tool that uses time for the chemical elements to travel through the GC column, the retention time as compared to known standards to identify the chemical. It is a good technique for simple mixtures and for situations where the chemicals of concern are known and calibrated before running samples. Though there are advantages and disadvantages of all the process but together these factors are helpful in evolution and advancement of laboratory processes and identification of elements.

Article Source: http://EzineArticles.com/9580518

Some Amazing Facts About Apple

interesting-facts-about-appleWith the release of every new iPhone begins the huge waiting lines to grab one. Quite obvious! Because of the range of smart features and apps iPhones offer, they are worth investing. While you might know a lot about the iPhone you are using, we are sure there are certain surprising and interesting facts about Apple you are unaware of.

We’ve compiled a few facts about iPhones and the top iOS app development company, Apple.

1. iPhone Before Apple’s iPhone – You might feel amazed to know that before Apple ever released the iPhone, the name was already patented by the Cisco Systems. In fact, they litigated Apple for naming its smartphone as ‘iPhone’. The first iPhone by Cisco was a VoIP phone, which allowed users to make Skype calls without using a computer. Ultimately, both the companies reached an agreement, and have kept their rights to the name.

2. iPhone was conceptualized in late 1980s – Back in 1983, the developer of Apple computer, Hartmut Esslinger idealized a landline phone that had features somewhat similar to today’s iPhone and iPad with a stylus-controlled interface. Though, the design was never developed into a real iPhone, it’s surprising that Apple had iPhone ideas years ago. Just imagine, how the iPhone landscape and custom iPhone app development would look if that old prototype in 1983 had been released.

3. Bono exist in every iPhone – If you look closely to your iPhone, you’ll find that the artist’s icon in your Music app is originally a silhouette of Bono Vertigo – the U2 singer.

4. The App Store was the first place to download an iOS app legally – One of the most astonishing facts about Apple was the App Store, which was the only place to download free or paid iOS apps legally.

5. Samsung Manufactures iPhone’s Processors – Now this might surprise you greatly. While it is true that Samsung and Apple are arch rivals in the smartphone field, they both are partnered with each other. Apple has given Samsung the contract to make its computer chips.

6. 700 iPhones sold by far – Last year in March, Apple CEO Tim Cook revealed that Apple has sold nearly 700 million iPhones. Reports on Apple’s earnings suggest that growing iPhone sales may soon touch 800 million.

7. Texting became the trend with iPhones – Over 22% of people believe that sending a SMS is far better than calling. It started when Apple presented SMS.

8. iPhone was the Invention of the Year – Seeing the popularity of Apple iPhone, the Time Magazine named it as the “Invention of the Year” in 2007. It was indeed a revolutionary development.

9. The iPhone was named Purple – In the early days when the iPhone was being engineered, the nickname for the new phone was named as “Purple”. Even the iPhone section at the Apple headquarters was called “Purple Dorm” by the developers.

10. 2 Million iPhone apps – According to the reports, there are over 2 million iOS apps available in the Apple app store (as of June 2016). With this, the Apple app store becomes the second largest app store after Android, which has over 2. 2 million apps. This also makes Apple as the top iOS app development company.

11. iPhone 4 names Antennagate – The new metal design of iPhone 4 caused extensive problems among the users when it was found that calls were getting disconnected on holding the phone in a certain way. Because of its severity, it earned the name of Antennagate.

12. Steve Jobs pranked with Starbucks – It was in 2007 when Apple was introduced for the first time by CEO Steve Jobs. He made a prank call to Starbucks and ordered over 4,000 lattes and cancelled it immediately. This was certainly a good thing for the barista who took that call.

Article Source: http://EzineArticles.com/9597141

How Does the ‘Microfiber’ Part of Cleaning Cloths Really Work?

You’ve undoubtedly heard about microfiber cleaning cloths. There are products out there that clean your kitchen counter, wipe your dishes and utensils off, and clean most flat surfaces including your mobile devices. They seem to be one of the best ways to keep your cell phone and tablet clean without ruining the screen with abrasive chemicals and wipes. But have you wondered why microfiber cloths work so well and why they are such a growing market?

Smaller Is Better!

This is one case where smaller really is better. The small ‘micro’ fibers in microfiber cloth do a better job of cleaning away dirt and grime. The reason is that the tiny microfibers can attach themselves to tiny particles of dirt. It’s really that simple. The smaller the micro fibers and cleaning pockets within the cloth, the more tiny specs of dirt and grime can be wipes away.

Larger cloth fibers will brush right over these smaller particles because they simply can’t pick them up. Ever drop your keys between the seats in your car and need to enlist some tiny kid-sized hands to retrieve them?

It’s the same principle, almost. Microfibers can get into those small spaces and grab the small dust and dirt particles that other standard cotton or polyester cloths leave behind.

Use the Force

The dust particles are attracted to the fibers by forces of attraction called van der Waals forces, named after their discoverer Johannes Diderik van der Waals, a Nobel-prize winning Dutch chemist.

In short the principle lays out how particles and atoms can be attracted to each other on a quantum level even without formally bonding.

The van der Waals forces are the same reason geckos can attach themselves to a ceiling, millions of tiny hairs, so many surface points that the lightweight gecko is held in place magnetically. Microfibers work in the same way. Millions of microfibers in a cloth use their combined van der Waals forces to pick up the dirt, dust, and other gross stuff you don’t want on your phone screen. This leaves an immaculate screen, not simply the appearance of a clean screen.

Many many people have wondered about the reason microfiber has blown up as a go to material for cleaning devices and flat surfaces. Now you know why. It is not only leveraging millions of touch points to collect millions of germs and particles, it’s also leveraging physics by magnetically attracting the dirt and grime.

Article Source: http://EzineArticles.com/9601878

Understanding Cutting Plotters

Cutting plotters are large scale cutting devices that produce ready cut graphics, mylar, and vinyl lettering. The devices are attached to a computer that directs their working. You can use the devices in vehicle graphics, billboard advertising, and sign making. The plotters provide you with speed and accuracy thus helping you complete your work fast and with great precision.

How the plotters work

As mentioned, the units are connected to a computer that is equipped with a specialized cutting program. The program sends the necessary cutting designs and dimensions to the device’s cutting knife so that you can achieve the cut that you are interested in. For the material to be cut, you have to roll or sheet feed it to the plotter. Once the material reaches the flat cutting surface, the cutting knife makes the necessary cuts and the material rolls off the cutting surface to make room for the next material.

You should note that the device can’t cut all the materials. Materials such as fabric and leather can’t be easily cut when you feed them using the roll or sheet fed process. The materials don’t have a rigid backing that allows them to move freely on the roll-feeders thus they should be cut using another method. Instead of feeding them through a roll feeder, you should place them on a vacuum cutting table that has small air holes. The vacuum suction system secures the material in place so that it can be cut by the cutting knife.

Factors to consider when buying cutting plotters

When buying the units you need to consider a number of factors. One of the factors is the size of the plotter. The best size of plotter you should go for should be informed by the size of your office. As mentioned, the cutting plotters are generally large but they come at different prices. Before you head to the store you should take the measurements of your space and buy a unit that will adequately fit there. You should leave enough space in front and behind the plotter to allow you to walk freely in the room. The extra space also allows the large paper to lay undisturbed when the other portions are being cut.

You should also consider where you are buying your machine from. As rule of thumb ensure that you buy from a reputable cutting plotters store. This calls for you to research and go with a company with the best reviews.

Article Source: http://EzineArticles.com/9601155