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Analytical Methods, Hyphenated Instruments

2000· other· en· W1749108605 on OpenAlex
Wayne P. Duncan

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueKirk-Othmer Encyclopedia of Chemical Technology · 2000
Typeother
Languageen
FieldChemistry
TopicMass Spectrometry Techniques and Applications
Canadian institutionsHewlett-Packard (Canada)
Fundersnot available
KeywordsChromatographyMass spectrometryChemistryIon-mobility spectrometrySample (material)Inductively coupled plasma mass spectrometryProcess engineeringSample preparationAnalytical techniqueGas chromatographyAnalytical Chemistry (journal)Engineering

Abstract

fetched live from OpenAlex

Abstract In 1990, Chemical Abstracts Service listed over 10 million substances in their Registry. Moreover, the growth of new compounds is exponential, leading to a doubling of known chemicals every eleven years. Thus there is an ever‐increasing need to efficiently identify substances and quantitate material with a high degree of confidence. Hyphenated instruments, combinations of accepted instrumental techniques where the sample is passed from one instrument directly into another, were developed to aid in solving this problem. Hyphenated analytical methods provide more complementary information in a shorter time period leading to faster and more reliable results, than data obtained from traditional instrumental methods. The number of types of analytical instruments that can be joined is very large. Combinations include separation‐separation, separation‐identification, and identification‐identification techniques. The combination of gas chromatography and mass spectrometry offers several advantages over the use of these techniques individually. Capillary gas chromatography provides very high separation efficiency. The mass spectrometer adds to this separation capability the unique ability to provide molecular structural information. Thus the gc/ms is a significant labor‐ and time‐saving device, accomplishing separation, component transfer, identification, and quantitation all in a single instrument. Gc/ms has been particularly valuable in the environmental field, where laboratories responsible for the monitoring of hazardous compounds depend heavily on gc/ms to separate components present in an environmental sample, and to identify and quantitate each. A related technique is that of inductively coupled plasma/mass spectrometry (icp/ms), where the plasma serves as a good interface and ion source for the quadrupole mass spectrometer. Gas chromatography/fourier transform infrared spectroscopy (gc/ftir) is especially powerful when combined with mass spectrometry. One of the factors involved in making the ternary gc/ir/ms system viable was the development of faster, more powerful computers to acquire, analyze, and report large quantities of data. One area where ir information particularly complements ms data is in the differentiation of isomeric compounds. Another analysis handled effectively by gc/ir/ms is essential oil characterization. The confidence level in the identification capability for gc/ir/ms is enhanced by the ability to search large spectral databases. The replacement of a gas chromatograph with a liquid chromatograph (lc) substantially enhances the separation of compounds which might decompose or which are not readily volatilized. However, removing the large quantities of lc solvent presents a challenge. Tandem mass spectrometry or ms/ms has been used for structure elucidation of unknowns and has the ability to provide sensitive and selective analysis of complex mixtures. Ms/ms is based on the characterization of selected ions in the mass spectrum of a sample through further fragmentation and analysis, and has found application in trace analysis of biological tissue, complex hazardous waste site samples, and human blood serum, and in drug testing.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow), Research integrity, Insufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: Not applicable
GenreCandidate signal: Other · Consensus signal: Other
Teacher disagreement score0.305
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0010.001
Science and technology studies0.0000.001
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0020.001
Insufficient payload (model declined to judge)0.0520.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.008
GPT teacher head0.295
Teacher spread0.287 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it