Notice bibliographique
Résumé
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.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,007 | 0,013 |
| Méta-épidémiologie (sens strict) | 0,003 | 0,002 |
| Méta-épidémiologie (sens large) | 0,002 | 0,002 |
| Bibliométrie | 0,008 | 0,006 |
| Études des sciences et des technologies | 0,002 | 0,004 |
| Communication savante | 0,004 | 0,006 |
| Science ouverte | 0,004 | 0,005 |
| Intégrité de la recherche | 0,003 | 0,008 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,052 | 0,063 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».