Misidentification of Organophosphate Esters during GC and GC/MS Analysis

Maney, John P.; Miller, Glenn C.; Comeau, Joseph K.; Wyck, N. E. Van; Fencl, Mary

doi:10.1021/es00008a038

Cited by 4 publications

(5 citation statements)

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“…Another source of spectrum variation arises from chemical reaction prior to fragmentation. The decomposition of organophosphate esters prior to analysis by GC/MS led to both an error in our reference library and a research publication . Reaction of a precursor ion prior to fragmentation is a quite different problem, which can occur in the ion source or even in the collision cell.…”

Section: False Negative Risk and Spectrum Variabilitymentioning

confidence: 99%

“…The decomposition of organophosphate esters prior to analysis by GC/MS led to both an error in our reference library and a research publication. 15 Reaction of a precursor ion prior to fragmentation is a quite different problem, which can occur in the ion source or even in the collision cell. LC solvents can, for example, associate with analyte ions.…”

Section: Variabilitymentioning

confidence: 99%

See 1 more Smart Citation

Mass Spectral Reference Libraries: An Ever-Expanding Resource for Chemical Identification

Stein¹

2012

Anal. Chem.

266

286

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The basic principles, practices, and pitfalls in the process of compound identification by searching mass spectral reference libraries are presented. Factors affecting the identification process are discussed as members of one of three major contributors to identification confidence: prior probability, risk of false negative results, and risk of false positive results. More general concerns and the problem of "unknown unknowns" are then explored.

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Section: False Negative Risk and Spectrum Variabilitymentioning

confidence: 99%

Section: Variabilitymentioning

confidence: 99%

Mass Spectral Reference Libraries: An Ever-Expanding Resource for Chemical Identification

Stein¹

2012

Anal. Chem.

266

286

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“…In order to examine the cause of death in detail, it would be necessary to determine the exact concentration of each compound. Several components in the samples were thermally unstable (5)(6)(7)(8) or easily hydrolyzed (6), so an alternate analytical method such as normal-phase liquid chro-148 Figure 5.…”

Section: Discussionmentioning

confidence: 99%

“…3 pyrophosphates and some phosphates undergo thermal degradation because of inadequate thermal stabilities (8). Thus, in this case, further quantitative analysis of the detected compounds was not performed.…”

Section: P=s Inmentioning

confidence: 99%

A Case of Suicide by Ingestion of Completely Decomposed Pesticide Diazinon

Ohta

Mori²,

Nakajima³

et al. 2006

Canadian Society of Forensic Science Journal

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Diazinon is an organophosphorus insecticide with a long history, that is widely used throughout the world. It is involved in many cases of suicide or accidental intoxication. Diazinon is considered to be relatively stable under normal conditions, but often undergoes self-decomposition during storage for unknown reasons. We report a case of suicide by ingestion of completely decomposed diazinon. The victim's stomach contents and the liquid that the victim drank underwent forensic examinations. The constituents of the liquid sample were detected from the stomach contents by conventional forensic analytical methods such as thin-layer chromatography and gas chromatography -mass spectrometry. Diazinon itself was not detected in either sample, but several decomposition products of diazinon were detected. In particular, monothiono-TEPP, which is much more toxic than diazinon itself, was detected as a major component. Therefore, in this case, the cause of death was thought to be poisoning by monothiono-TEPP and/or other ingredients such as xylenes. The most abundant components in the samples were 6,6′ ′-thiobis (2-isopropyl-4-methylpyrimidine) and 2-isopropyl-4-ethylthio-6-methylpyrimidine, which are known to be characteristic degradation products of diazinon. These compounds were easily detected, thus providing persuasive evidence that the liquid the victim drank was decomposed diazinon. RÉSUMÉ Le diazinon est un insecticide organophosphoré avec une longue histoire d'utilisation à travers le monde. Il est impliqué dans plusieurs cas de suicide ou d'intoxication accidentelle. Dans des conditions normales, cette substance est relativement stable mais peut se décomposer durant sa conservation pour des raisons inconnues. Nous rapportons ici un cas de suicide par absorption de diazinon complète-ment dégradé. Le contenu gastrique de la victime et le liquide ingéré ont étéanalysés;les constituants du liquide ont été décelés dans le contenu gastrique par chromatographie sur couche mince et chromatographie gazeuse/spectrométrie de masse. La présence de diazinon n'a pu être démontrée dans aucun des échantillons cependant plusieurs de ses produits de décomposition ont pu y être décelés particulièrement le monothiono-TEPP,composant majeur,plus toxique que le diazinon lui-même. La cause de décès dans ce cas fut donc attribuée à une intoxication mixte au monothiono-TEPP et/ou autres substances comme les xylènes.Deux des composés les plus abondants du liquide étaient le 6,6′−thiobis (2-isopropyl-4-methylpyrimidine) et le 2-isopropyl-4-ethylthio-6-methylpyrimidine, produits de dégradation connus du diazinon;ces substances furent facilement décelées nous permettant ainsi de démontrer de façon convaincante que le liquide absorbé par la victime était bien du diazinon décomposé.

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“…Although infrequent and isolated, there is at least one example of a multilaboratory blunder due to commercially available standards unknowingly degrading to another environmental contaminant (20). As a result, many laboratories could have reported the wrong compound for years.…”

Section: Blunders Random Errors and Other Demonsmentioning

confidence: 99%