Wednesday, April 25, 2012

New Elements Added to the Periodic Table Greyhound Chromatography

Two new elements were recently added to the periodic table after a three-year review by the governing bodies of chemistry and physics. The elements are currently unnamed, they have temporary titles of ununquadium and ununhexium but final names have yet to be decided. Both elements are highly radioactive and exist for less than a second before decaying into lighter atoms.

The review was conducted by a joint working party of the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP). The working party concluded that elements 114 and 116 fulfilled criteria for official inclusion in the table. In recent years, there have been several claims by laboratories for the discovery of new chemical elements at positions 113, 114, 115, 116 and 118 on the periodic table, to date only 114 and 116 fulfil the strict criteria.

The discovery of both elements has been credited to a collaborative team based at the Joint Institute for Nuclear Research in Dubna, Russia, and Lawrence Livermore National Laboratory in California, US.

Download a free A3 Poster of the Periodic Table.

Over 70 High Purity Standards inc. single element standards are available from Greyhound Chromatography and Allied Chemicals. Concentrations include both 1000 and 10.00 in aqueous solution, (unless otherwise noted). Most standards are packaged in 50,100, 250 and 500 mL HDPE or LDPE laboratory grade bottles. The density is provided on the Certificate of Analysis as additional information for the user.

The accuracy of all standards is verified against NIST Spectrometric Standard Solutions. A certificate of Analysis and Safety Data Sheet are included with each standard. Standards are certified accurate for a period of 18 months from the date of shipment unless stated otherwise on the Certificate of Analysis.

The periodic table is now ubiquitous within the academic discipline of chemistry, providing a useful framework to classify, systematise, and compare all of the many different forms of chemical behaviour. The table has found many applications in chemistry, physics, biology, and engineering, especially chemical engineering.

In 1789, Antoine Lavoisier published a list of 33 chemical elements. Although Lavoisier grouped the elements into gases, metals, non-metals, and earths, chemists spent the following century searching for a more precise classification scheme. In 1829, Johann Wolfgang Döbereiner observed that many of the elements could be grouped into triads (groups of three) based on their chemical properties. Lithium, sodium, and potassium, for example, were grouped together as being soft, reactive metals. Döbereiner also observed that, when arranged by atomic weight, the second member of each triad was roughly the average of the first and the third. This became known as the Law of triads. German chemist Leopold Gmelin worked with this system, and by 1843 he had identified ten triads, three groups of four, and one group of five. Jean Baptiste Dumas published work in 1857 describing relationships between various groups of metals. Although various chemists were able to identify relationships between small groups of elements, they had yet to build one scheme that encompassed them all.

German chemist August Kekulé had observed in 1858 that carbon has a tendency to bond with other elements in a ratio of one to four. Methane, for example, has one carbon atom and four hydrogen atoms. This concept eventually became known as valency. In 1864, fellow German chemist Julius Lothar Meyer published a table of the 49 known elements arranged by valency. The table revealed that elements with similar properties often shared the same valency.

Of the 94 naturally occurring elements, those with atomic numbers 1 through 40 are all considered to be stable isotopes. Elements with atomic numbers 41 through 82 are apparently stable (except technetium and promethium) but theoretically unstable, or radioactive. The half lives of elements 41 through 82 are so long however that their radioactive decay has yet to be detected by experiment. These theoretical radionuclides have half lives at least 100 million times longer than the estimated age of the universe. Elements with atomic numbers 83 through 94 are unstable to the point that their radioactive decay can be detected. Some of these elements, notably thorium (atomic number 90) and uranium (atomic number 92), have one or more isotopes with half lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before the formation of our solar system. For example, at over 1.9×1019 years, over a billion times longer than the current estimated age of the universe, bismuth-209 (atomic number 83) has the longest known alpha decay half life of any naturally occurring element. The very heaviest elements (those beyond plutonium, atomic number 94) undergo radioactive decay with half lives so short that they have only been observed as the result of experimental observation.

Apart from the hydrogen and helium in the universe, which are thought to have been mostly produced in the Big Bang, the chemical elements are thought to have been produced by one of two later processes—either cosmic ray spallation (important for lithium, beryllium and boron), or stellar nucleosynthesis (which produces all elements heavier than boron). Oxygen is the most abundant element in the Earth’s crust, making up almost half of its mass Relatively small amounts of elements continue to be produced on Earth as products of natural transmutation processes. This includes production by cosmic rays or other nuclear reactions (see cosmogenic and nucleogenic nuclides), or as decay products of long-lived primordial nuclides.

English chemist John Newlands produced a series of papers in 1864 and 1865 that described his own classification of the elements: he noted that when listed in order of increasing atomic weight, similar physical and chemical properties recurred at intervals of eight, which he likened to the octaves of music. This law of octaves, however, was ridiculed by his contemporaries and the Chemical Society refused to publish his work. Nonetheless, Newlands was able to draft an atomic table and use it to predict the existence of missing elements, such as germanium.

Russian chemistry professor Dmitri Ivanovich Mendeleev and Julius Lothar Meyer independently published their periodic tables in 1869 and 1870, respectively. They both constructed their tables in a similar manner: by listing the elements in a row or column in order of atomic weight and starting a new row or column when the characteristics of the elements began to repeat. The success of Mendeleev’s table came from two decisions he made: The first was to leave gaps in the table when it seemed that the corresponding element had not yet been discovered. Mendeleev was not the first chemist to do so, but he was the first to be recognised as using the trends in his periodic table to predict the properties of those missing elements, such as gallium and germanium. The second decision was to occasionally ignore the order suggested by the atomic weights and switch adjacent elements, such as cobalt and nickel, to better classify them into chemical families. With the development of theories of atomic structure, it became apparent that Mendeleev had listed the elements in order of increasing atomic number.

Tuesday, April 24, 2012

Drug testing for the 2012 Olympics Greyhound Chromatography

Analytical Reference Standards from Greyhound Chromatography

Stimulants, Anabolic Steroids and Agents, Diuretics, Peptide Hormones and Analogues are some of the substances that enhance athletic performance that are banned in sports.

The International Olympic Committee (IOC) introduced the first drug use controls at the 1968 Winter Olympics. These controls eventually evolved into a systematic testing regimen that all Olympic athletes must adhere to. Testing of athletes for performance enhancing drugs includes both urine and blood tests. As of 1999 the authoritative body on the use of performance enhancing drugs is the World Anti-Doping Agency (WADA). This organisation oversees the testing of athletes for several sports federations and the Olympic Games.

Doping control is a huge issue in sports performance today. Always a topical subject when high profile events are due to take place, the controversial subject is brought in to the media arena when events such as The Tour De France and the Olympic Games are in progress. Competitions where athletes are strictly monitored and tested attract media attention, particularly when athletes are found to be using substances that are on the banned list. However, testing takes place all over the world every day for every competitive sporting event. Headlines over recent years have included high profile sports personalities who have been banned from competing in their respective sports following mandatory tests, there has been some discussion about false positives being recorded because of an athlete’s body reacting with prescription drugs. This highlights the need for stringent testing, research and analysis.

Gas Chromatography is used extensively by testing laboratories to detect banned substances in blood and urine samples. The gas chromatograph-mass spectrometer (GC-MS), which combines two analytical instruments, is most often used in drug testing. The GC (gas chromatograph) separates the ingredients of the mixture, and the mass spectrometer identifies them. To ensure that urine and blood samples from the athlete are sent to the laboratory in a way that ensures that they are identified to the individual giving the sample, without any possible confusion as to whom they belong, is a complex and closely regulated procedure. In most sports drug testing programs an official witness’s urination into a plastic cup, or the taking of a blood sample. The sample is then poured into bottles that are sealed to exclude contamination and tampering, and shipped to the testing laboratory. GC-MS analysis begins with sample preparation. Steps to remove water and salts and to concentrate target drugs can take several hours. Greyhound Chromatography, a Wirral based company, has been supplying Chromatography consumables to Research and Analysis laboratories for 30 years. Greyhound manufactures its own range of GC Capillary columns which includes over 1,000 different columns that are used for many different analyses, these include testing samples from athletes.

Upon injection into the GC, the sample is vaporized and swept along a hair-thin glass tube (capillary column) by a flow of inert gas such as helium. Different compounds travel at different speeds due to variations in boiling point, polarity, and solubility in the coating of the inner wall of the tube. The compounds exit the GC one by one, each at a different, characteristic time (the retention time), and enter the mass spectrometer. The mass spectrometer breaks molecules into fragments and measures their mass-to-(electrical) charge ratio, m/z.

Fragmentation patterns can be interpreted to deduce the structure of an unknown molecule. In drug testing, because fragmentation patterns are characteristic and reproducible, a drug is identified and its presence confirmed by matching both its GC retention time and mass spectrum with those of an authentic reference standard. Greyhound Chromatography supplies Analytical Reference Standards of very high purity to ensure accurate detection of banned substances (over 100,000 standards are available as neat products, solutions and customised mixtures) and also supplies laboratory consumables including, GC Columns, Syringes, glassware, testing and analysis collection cups.

The science behind the analysis and detection of samples is straightforward, the moral and ethical arguments that surround athletes taking performance enhancing substances are not so simple and will be debated for as long as competitive sports are conducted.

Stimulants:
Amiphenazole
Amphetamine
Bemigride
Benzphetamine
Bromantan
Caffeine
Chlorphentermine
Cocaine
Cropropamide
Crothetamine
Dimethylamphetamine
Doxapram
Ephedrine
Ethamivan
Ethylamphetamine


Anabolic Agents:
Anabolic Steriods
Androstenediol
Androstenedione
Boldenone
Clostebol
Dehydrochlormethyltestosterone
Testosterone
Dehydroepiandrosterone
(DHEA)
Dihydrotestosterone (DHT)
Dromostanolone
Fluoxymesterone
Mesterolone
Methandienone
Methenolone


Diuretics:
Acetazolamide
Bendroflumethiazide
Benzthiazide
Bumetanide
Fencamfamine
meclofenoxate
methamphetamine
methylphenidate
nikethamide
pemoline
pentetrazol
phendimetrazine
phenmetrazine
picrotoxine
pipradol
prolintane
strychnine
and related compounds
methyltestosterone
nandrolone
norandrostendiol
norandrostenedione
norethandrolone
oxandrolone
oxymesterone
oxymetholonestanozolol
testosterone
and related compounds

Other Anabolic Agents
clenbuterol
hydroflumethiazide
methyclothiazide
metolazone
polythiazide

Chlorothiazide quinethazone
Chlorthalidone spironolactone
Ethacrynic acid triamterene
Flumethiazide trichlormethiazide
Furosemide and related compounds
Hydrochlorothiazide

Peptide Hormones and Analogues
Chorionic gonadotrophin (HCG-human chorionic gonadotrophin)
Corticotrophin (ACTH)
Growth hormone (HGH, somatotrophin)
All the respective releasing factors of the above-mentioned substances also are
banned.
Erythropoietin (EPO)


The following is a definition of positive for this list.
• For Caffeine – if the concentration in urine exceeds 12 micrograms/ml
• For Testosterone – if the administration of testosterone or the use of any other
manipulation has the result of increasing the ratio of the total concentration of
testosterone to that of epitestosterone in the urine to greater that 6:1, unless
there is evidence that this ratio is due to a physiological or pathological
condition.

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