the-french-artist/wikipedia_20220301.simple_sentence_embeddings huggingface dataset:
Gas chromatography–mass spectrometry 
 The difference in the chemical properties between different molecules in a mixture will separate the molecules as the sample travels the length of the column.
Gas chromatography–mass spectrometry 
 The molecules take different amounts of time (called the retention time) to come out of (elute from) the gas chromatograph.
Gas chromatography–mass spectrometry 
 This allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately.
Gas chromatography–mass spectrometry 
 The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass to charge ratio.
Gas chromatography–mass spectrometry 
 These two machines, used together, allow a much finer precision of substance identification than either unit used separately.
Gas chromatography–mass spectrometry 
 It is not possible to make an accurate identification of a particular molecule by gas chromatography or mass spectrometry alone.
Gas chromatography–mass spectrometry 
 These detectors cannot separate different molecules that happen to take the same amount of time to travel through the column. (
Gas chromatography–mass spectrometry 
 The co-eluting molecules will confuse the computer programs that are reading a single mass spectrum for both molecules.
Gas chromatography–mass spectrometry 
 Sometimes two different molecules can also have a similar pattern of ionized fragments in a mass spectrometer (mass spectrum).
Gas chromatography–mass spectrometry 
 It is extremely unlikely that two different molecules will behave in the same way in both a gas chromatograph and a mass spectrometer.
Gas chromatography–mass spectrometry 
 Therefore, if a mass spectrum matches the analyte of interest, the retention time of that spectrum can be checked against a characteristic GC retention time to increased confidence that the analyte is in the sample.
Gas chromatography–mass spectrometry 
 However these particular instruments are expensive and bulky and not typically found in high-throughput service laboratories.
Gas chromatography–mass spectrometry 
 Other detectors are used such as time of flight (TOF), tandem quadrupoles (MS-MS) (see below), or in the case of an ion trap MSn.
Gas chromatography–mass spectrometry 
 A mass spectrometer is typically used in one of two ways: Full Scan or Selective Ion Monitoring (SIM).
Gas chromatography–mass spectrometry 
 When collecting data in the full scan mode, a target range of mass fragments is selected and put into the instrument's method.
Gas chromatography–mass spectrometry 
 The determination of what range to use is largely set by what one expects being in the sample while being aware of the solvent and other possible interferences.
Gas chromatography–mass spectrometry 
 If an MS looks for mass fragments with a very low m/z, it may detect air or other possible interferring factors.
Gas chromatography–mass spectrometry 
 The machine will perform fewer scans per second because each scan will take more time to detect a wider range of mass fragments.
Gas chromatography–mass spectrometry 
 It provides more information than SIM when it comes to confirming or resolving compounds in a sample.
Gas chromatography–mass spectrometry 
 Most instruments are controlled by a computer which operates a computer program called an "instrument method."
Gas chromatography–mass spectrometry 
 The instrument method controls the temperature in the GC, the MS scan rate and the range of fragment sizes being detected.
Gas chromatography–mass spectrometry 
 When a chemist is developing an instrument method, the chemist sends test solutions through the GS-MS in full scan mode.
Gas chromatography–mass spectrometry 
 This checks the GC retention time and the mass fragment fingerprint before moving to a SIM instrument method.
Gas chromatography–mass spectrometry 
 Specialized GC-MS instruments, such as explosive detectors, have an instrument method pre-loaded at the factory.
Gas chromatography–mass spectrometry 
 The advantages of SIM are that the detection limit is lower since the instrument is only looking at a small number of fragments (e.g. three fragments) during each scan.
Gas chromatography–mass spectrometry 
 Since only a few mass fragments of interest are being monitored, matrix interferences are typically lower.
Gas chromatography–mass spectrometry 
 To improve the chances of reading a positive result correctly, the ion ratios of the various mass fragments are comparable to a known reference standard.
Gas chromatography–mass spectrometry 
 After the molecules travel the length of the column, pass through the transfer line and enter into the mass spectrometer they are ionized by various methods.
Gas chromatography–mass spectrometry 
 The molecules enter into the MS (the source is a quadrupole or the ion trap itself in an ion trap MS) where they are hit with free electrons emitted from a filament.
Gas chromatography–mass spectrometry 
 The electrons hit the molecules, causing the molecule to fragment in a characteristic way that can be repeated.
Gas chromatography–mass spectrometry 
 This "hard ionization" technique results in the creation of more fragments of low mass to charge ratio (m/z).
Gas chromatography–mass spectrometry 
 In contrast, "soft ionization" is placing a charge on the sample molecule by hitting it with an introduced gas.
Gas chromatography–mass spectrometry 
 The molecular fragmentation pattern depends on the electron energy applied to the system, typically 70 eV (electron Volts).
Gas chromatography–mass spectrometry 
 The use of 70 eV helps to compare the spectra generated from the test sample against known library spectra. (
Gas chromatography–mass spectrometry 
 The library spectra can come from manufacturer-supplied software or software developed by the National Institute of Standards (NIST-USA)).
Gas chromatography–mass spectrometry 
 The software searches the library spectra using a matching algorithm such as Probability Based Matching or dot-product matching.
Gas chromatography–mass spectrometry 
 Many method standardization agencies now control these algorithms and methods to assure their objectivity.
Gas chromatography–mass spectrometry 
 In chemical ionization (CI), a reagent gas, typically methane or ammonia is put into the mass spectrometer.
Gas chromatography–mass spectrometry 
 Either way, the reagent gas will interact with the electrons and analyte and cause a 'soft' ionization of the molecule of interest.
Gas chromatography–mass spectrometry 
 This is because CI produces at least one mass fragment with a weight, that is nearly the same as the molecular weight of the analyte of interest.
Gas chromatography–mass spectrometry 
 In Positive Chemical Ionization (PCI) the reagent gas interacts with the target molecule, most often with a proton exchange.
Gas chromatography–mass spectrometry 
 In Negative Chemical Ionization (NCI) the reagent gas decreases the impact of the free electrons on the target analyte.
Gas chromatography–mass spectrometry 
 This is done by comparing the relative concentrations among the atomic masses in the generated mass spectrum.
Gas chromatography–mass spectrometry 
 Comparative analysis essentially compares the given spectrum to a spectrum library to see if its characteristics are present for some known sample in the library.
Gas chromatography–mass spectrometry 
 This is best performed by a computer because there are many visual distortions that can take place due to variations in scale.
Gas chromatography–mass spectrometry 
 Computers can also correlate more data (such as the retention times identified by the GC), to more accurately relate certain data.
Gas chromatography–mass spectrometry 
 The value of this parent peak can be used to fit with a chemical formula containing the various elements which are believed to be in the compound.
Gas chromatography–mass spectrometry 
 Because a molecule's structure and bonds break apart in characteristic ways, they can be identified from the difference in peak masses.
Gas chromatography–mass spectrometry 
 Typically, this identification is done automatically by computer programs which come with the instrument.
Gas chromatography–mass spectrometry 
 Those programs match the spectra against a library of known compounds that have same list of elements which could be present in the sample.
Gas chromatography–mass spectrometry 
 But, selective ion monitoring (SIM) only monitors selected peaks associated with a specific substance.
Gas chromatography–mass spectrometry 
 Chemists assume that at a given retention time, a set of ions is characteristic of a certain compound.
Gas chromatography–mass spectrometry 
 SIM works best when the analyst has previous information about a sample or is only looking for a few specific substances.
Gas chromatography–mass spectrometry 
 When the amount of information collected about the ions in a given gas chromatographic peak decreases, the sensitivity of the analysis increases.
Gas chromatography–mass spectrometry 
 When a second phase of mass fragmentation is added, for example using a second quadrupole in a quadrupole instrument, it is called tandem MS (MS/MS).
Gas chromatography–mass spectrometry 
 MS/MS are good at measuring low levels of target compounds in a sample with a matrix of background compounds that are not of interest.
Gas chromatography–mass spectrometry 
 Both quadrupoles can be used in scanning or static mode, depending on the type of MS/MS analysis used.
Gas chromatography–mass spectrometry 
 Types of analysis include product ion scan, precursor ion scan, Selected Reaction Monitoring (SRM) and Neutral Loss Scan.
Gas chromatography–mass spectrometry 
 For example: When Q1 is in static mode (looking at one mass only as in SIM), and Q3 is in scanning mode, one obtains a so-called product ion spectrum (also called "daughter spectrum").
Gas chromatography–mass spectrometry 
 From this spectrum, one can select a prominent product ion which can be the product ion for the chosen precursor ion.
Gas chromatography–mass spectrometry 
 Many chemists believe that GC-MS is the best tool for monitoring organic pollutants in the environment.
Gas chromatography–mass spectrometry 
 But for most organic analysis of environmental samples, including many major classes of pesticides, GC-MS is very sensitive and effective.
Gas chromatography–mass spectrometry 
 GCMS/MS is especially useful here as samples often contain very complex matrices and results, used in court, need to be highly accurate.
Gas chromatography–mass spectrometry 
 It helps to find drugs and/or poisons in biological specimens taken from suspects, victims, or a dead body.
Gas chromatography–mass spectrometry 
 After the September 11, 2001 terrorist attacks, explosive detection systems have become a part of all US airports.
Gas chromatography–mass spectrometry 
 The first is Thermo Detection (formerly Thermedics), which produces the EGIS, a GC-MS-based line of explosives detectors.
Gas chromatography–mass spectrometry 
 Foods and beverages contain a lot of aromatic compounds, some naturally present in the raw materials and some forming during processing.
Gas chromatography–mass spectrometry 
 GC-MS is extensively used for the analysis of these compounds which include esters, fatty acids, alcohols, aldehydes, terpenes, etc.
Gas chromatography–mass spectrometry 
 It is also used to detect and measure contaminants from spoilage or adulteration which may be harmful.
Gas chromatography–mass spectrometry 
 The material in the comet 67P/Churyumov-Gerasimenko will be analysed by the Rosetta mission with a chiral GC-MS in 2014.
Gas chromatography–mass spectrometry 
 These tests can find dozens of congenital metabolic diseases (also known as Inborn error of metabolism).
Gas chromatography–mass spectrometry 
 These compounds are normally not present but appear in individuals suffering with metabolic disorders.
Gas chromatography–mass spectrometry 
 It is now possible to test a newborn for over 100 genetic metabolic disorders by a urine test at birth based on GC-MS.
Gas chromatography–mass spectrometry 
 In combination with isotopic labeling of metabolic compounds, the GC-MS is used for determining metabolic activity.
Gas chromatography–mass spectrometry 
 Most applications are based on the use of 13C as the labeling and the measurement of 13C-12C ratios with an isotope ratio mass spectrometer (IRMS).
Gas chromatography–mass spectrometry 
 A IRMS is an mass spectrometer with a detector designed to measure a few select ions and return values as ratios.
Lacey Brown 
 Lacey Elizabeth Brown  (born August 13, 1985) is an American singer-songwriter, record producer, violinist, painter, model and fashion designer.
Lacey Brown 
 Born on August 13, 1985, Brown is the daughter of the pastors of Victory Church, a local Christian Church, in Amarillo.
Lacey Brown 
 There, she served as Venue (Victory's college-aged group) director and taught civics and Christian values to Victory's internship students.
Lacey Brown 
 Her musical influences include folk and country, as well as rock music, such as Lady Antebellum, Kings of Leon, Coldplay, and U2, apart from Patsy Cline, Joni Mitchell, Dolly Parton, and Pete Yorn.
Lacey Brown 
 Brown first auditioned for the eighth season of American Idol, where she made it into the Top 54 of the Hollywood rounds.
Lacey Brown 
 Brown later auditioned in Orlando, Florida with the song "Over the Rainbow", from The Wizard of Oz, by Judy Garland.
Lacey Brown 
 The judges all loved her performance, including guest judge Kristin Chenoweth, and she made it through to the next round.
Lacey Brown 
 During Hollywood week, her performance of "What a Wonderful World" was featured as a montage for contestants who made it to the Top 24.
Lacey Brown 
 The judges did not like her performance of "Kiss Me" by Sixpence None the Richer during the second week.
Lacey Brown 
 Her cover of Brandi Carlile's "The Story", on the final night before the finals, was considered to be better.
Lacey Brown 
 Brown's performance of "Ruby Tuesday" by The Rolling Stones (she stated that her version is the one by Melanie Safka), was described by the judges as not having energy, but Simon Cowell added that there was nothing wrong with her vocals.
Lacey Brown 
 The song "What a Wonderful World" was played at the beginning of the episode, with a montage of the Top 12's journey, setting the tone for her elimination.
Lacey Brown 
 Angry fans did not watch the show which had "the smallest audience among 18-49 year-olds for a regularly scheduled in-season episode in "Idol" history".
Lacey Brown 
 Brown thanked her fans for their support and plans to return to her hometown, after doing interviews in New York.
Lacey Brown 
 She says she will try acting (from a criticism to her by Simon Cowell) as well as a career in music.
Lacey Brown 
 In her final moments on the show, she said she might try country music although her MySpace page lists "pop" and "folk" as her genres.
Lacey Brown 
 After leaving Idol, Brown gave several media interviews with Entertainment Weekly, USA Today, The Los Angeles Times, People, several Fox affiliates, MTV, E!,
Lacey Brown 
 with Ryan Seacrest on his radio show (On Air with Ryan Seacrest), with Ellen DeGeneres on The Ellen DeGeneres Show, along with several in New York, including the Wendy Williams Show and The Late Show with David Letterman, where she performed "What a Wonderful World".
Lacey Brown 
 Among the finalists, her closest friends are Paige Miles and Lee DeWyze although she is friends with all of them including Siobhan Magnus and Katie Stevens.
Lacey Brown 
 She said in these interviews that she is planning to continue her career in music but she is also open to any offers that may come to her.
Lacey Brown 
 In 2011, Brown signed a management contract with Tracy Lawrence and she will be touring at the CMA Fest in Nashville in June 2011.
Lacey Brown 
 The alternative country EP Let It Go, with five songs on it, was released on May 31, 2011 through the independent (self-owned) record label LEB Records.
Napkin 
 A napkin, or face towel (also in Canada, the United Kingdom, Australia: serviette) is a rectangle of cloth used at the table for wiping the mouth while eating.
Chun Kuk Do 
 Chun Kuk Do (, commonly abbreviated as CKD) is a martial art (or type of fighting style) that Chuck Norris created.
Nevers 
 Nevers is a commune in the Nièvre department in the Bourgogne-Franche-Comté region in central France.
Nevers 
 It is the main city of the department and one of the largest city of the region, after Dijon and Chalon-sur-Saône.
Nevers 
 Julius Caesar named the town as Noviodunum but later was named as Nebirnum, after the name of the river.
Nevers 
 Nevers was the capital of the old province of Nivernais and became the capital of Nièvres on 4 March 1790 with the creation of the departments in France.
Nevers 
 Nevers is at about  to the southeast of Paris, on the confluence of the Loire and the Nièvre rivers.
Nevers 
 Nevers is surrounded by the communes Varennes-Vauzelles, Coulanges-lès-Nevers, Saint-Éloi, Sermoise-sur-Loire, Challuy and Marzy.
Nevers 
 The Köppen climate classification type for Nevers is an "Oceanic climate" (also known as Maritime Temperate climate) and of the subtype Cfb.
Nevers 
 The inhabitants of Nevers are known, in French, as Nivernais (women: Nivernaises) but they are also known as Neversois (women: Neversoises), leaving Nivernais for the people of the department.
Nevers 
 Nevers forms, together with other 6 communes, the urban area of Nevers with a population of 59,444 inhabitants (2013) and an area of .
Nevers 
 This urban area is the centre of the metropolitan area of Nevers, formed by 57 communes, with a population of 100,768 inhabitants (2013) and an area of .
Nevers 
 Nevers is the prefecture of the Nièvre department, the capital of the arrondissement of Nevers and the administrative centre () of four cantons:
Nevers 
 Nevers-1 formed by the commune Coulanges-lès-Nevers and part of Nevers, with 11,738 inhabitants (2014).
Nevers 
 The Nevers Cathedral (Cathédrale Saint-Cyr-et-Sainte-Julitte) is a Roman Catholic cathedral, dedicated to Saints Cyricus and Julitta.
Nevers 
 The Palais Ducal ("Ducal Palace", now occupied by the courts of justice and an important ceramic museum) was built in the 15th and 16th centuries.
Andrea Moda Formula 
 Andrea Moda Formula, commonly referred to as Andrea Moda, was a Formula One team which raced in the 1992 Formula One season.
Andrea Moda Formula 
 The team was excluded from the opening race in South Africa after not paying the required $100,000 entry fee for new teams.
Andrea Moda Formula 
 Even though the team was entered in the next race, in Brazil, with drivers Roberto Moreno and Perry McCarthy, the cars were still not ready.
Andrea Moda Formula 
 At the fifth race in San Marino the car was finally ready but McCarthy did not receive his Super License, which is required to race a F1 car.
Andrea Moda Formula 
 However, Moreno finally qualified his car in Monaco, only to retire during the race due to an engine problem.
Andrea Moda Formula 
 In Canada, the team did not have engines because Sassetti did not pay the engine supplier, Judd, the money.
Andrea Moda Formula 
 In August of 1992, the FIA warned the team that they might be excluded (disqualified, does not count) from the championship.
Andrea Moda Formula 
 It was a known fact that McCarthy was barely given a chance, since the team could not afford to properly run two cars, so they mainly worked on Moreno's car while McCarthy was only there to meet the rules of having two cars in the race.
Andrea Moda Formula 
 The team was not allowed in the paddock at the Italian Grand Prix, because the FIA banned the team brought Formula One into disrepute.
Size-exclusion chromatography 
 Recall a mixture can be composed of many substances each with different physical and chemical properties which can be used to differentiate them.
Size-exclusion chromatography 
 SEC essentially allows components that are larger in size to exit the column (elute) first while components that are smaller in size will exit the column last.
Size-exclusion chromatography 
 A typical column used in SEC has two substances called phases that interact with the mixture and these substances help force the separation of the mixture.
Size-exclusion chromatography 
 The mobile phase is a solvent which helps carry the mixture down the column, and the stationary phase which does not move.
Size-exclusion chromatography 
 Unlike other chromatography methods, the stationary phase used in SEC does not exploit the polarity of each component.
Size-exclusion chromatography 
 A common porous solid is silica which has a diameter of 5-10µm and a pore sizes ranging from 100-1000Å. Silica provides excellent rigidity and will not move throughout the column.
Size-exclusion chromatography 
 Porous solids are also stable at high pressures and temperatures which allows for the use of a vast variety of solvents.
Size-exclusion chromatography 
 Unfortunately silica particles have a tendency to allow absorb soluble components and they have the capacity to break down components into atoms.
Size-exclusion chromatography 
 The structure of gel is vastly different from a porous solid because gel’s have a polymer-like (a repeating structure of the same substance) structure.
Size-exclusion chromatography 
 Gels have been shown to be more effective than porous solids at allowing components through its pores.
Size-exclusion chromatography 
 Gels have pore sizes ranging from 100-100000Å. So how is it that larger molecules exit the column before smaller molecules?
Size-exclusion chromatography 
 The porous material will not allow larger molecules to pass so these molecules go to the next pore and again they cannot pass.
Size-exclusion chromatography 
 Remember there is volume inside the column that is not inhabited by the stationary phase which allows for the flow of both the mobile phase and the sample.
Size-exclusion chromatography 
 These larger molecules then find themselves at the bottom of the column whereas smaller molecules have a longer path to travel.
Size-exclusion chromatography 
 The smaller a molecule is, the greater the chance is that it can fit into a pore which means the longer it spends inside the column.
Size-exclusion chromatography 
 The exclusion limit defines the maximum molecular weight that can enter a pore, while the permeation limit signifies the minimum molecular weight to enter a pore.
Size-exclusion chromatography 
 The curve itself is called the permeation region and this provides a range of molecular weights which could be found in the experiment.
Size-exclusion chromatography 
 Normally peaks found in liquid or gas chromatography indicates how many components are in a mixture if the number of components is unknown and the relative amount of each component in the mixture within a given range.
Size-exclusion chromatography 
 In the case of SEC these peaks indicate the relative amount of each component (based on molecular weight) within the permeation region.
Size-exclusion chromatography 
 Depending on the chemical characteristics of the mixture and its components the process could be quick or slow.
Size-exclusion chromatography 
 Next there is low mass loss since the sample theoretically is not supposed to come interact with the stationary phase.
Size-exclusion chromatography 
 Last the stability of the stationary phase allows close packing to provide greater separation of components in the sample.
Size-exclusion chromatography 
 A clear disadvantage to SEC is with short retention times the peaks overlap and little information could be extracted from such data.
Size-exclusion chromatography 
 Resolution (how well two peaks can two peaks be distinguished between) must be sacrificed if the process is to be shorter in time.
Size-exclusion chromatography 
 For example if component A has molecular mass equal to 900 g/mol and component B has molecular mass equal to 950 g/mol, SEC will show one peak in this region and both components will be represented by the same peak.