Mass spectra of methyl-branched hydrocarbons from eggs of the tobacco hornworm

Nelson, Dennis R.; Sukkestad, Dennis R.; Zaylskie, Richard G.

doi:10.1016/s0022-2275(20)39405-0

Cited by 107 publications

(10 citation statements)

References 15 publications

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“…Compounds were identified by comparison of their MS to those of authentic standards and/or to those already described in the literature [30]. Determination of the branching position of methyl substituted alkanes was based on the fragmentation patterns reported [31] and were supported by their CI-MS when required.…”

Section: Preparation Of Extractsmentioning

confidence: 99%

Cuticular and Internal Chemical Composition of Biting Midges Culicoides spp. (Diptera: Ceratopogonidae), Potential Vectors of Viral Diseases

González

López

Rosell

et al. 2014

Natural Product Communications

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The chemical profile of the cuticle and internal tissues of four species of Culicoides have been studied for the first time by gas chromatography-mass spectrometry. The chemical composition of females of C. obsoletus s.l. and C. lupicaris, vectors of diverse viral diseases, have been compared with that of other biting midges, such as C. kibunensis and C. fascipennis, and the non-biting midge Forcipomyia bipunctata. A total of 61 compounds belonging to 8 major chemical classes were identified in cuticular and internal tissues in n-hexane extracts. The compounds include carboxylic acids (CAs) (C6-C20), with C16:0, C16:1 and C18:1 being dominant, branched hydrocarbons (C29 to C38 mono/di/trimethylalkanes), linear hydrocarbons (C15 to C33, mainly odd chain carbons), terpenes (geranylacetone, geranylgeraniol acetate, squalene, terpenic alcohol), steroids (cholesterol), aldehydes (C9-C10 and even chain C20 to C30), and esters. The chemical profile depends on the species and whether the extracts are external (cuticle) or internal. The contents of linear and branched hydrocarbons and aldehydes was high in cuticular extracts but practically absent in internal tissues, which were, in contrast, rich in CAs, terpenes and steroids. The results are discussed and compared with other Culicoides midges and mosquito-related species.

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Section: Preparation Of Extractsmentioning

confidence: 99%

Cuticular and Internal Chemical Composition of Biting Midges Culicoides spp. (Diptera: Ceratopogonidae), Potential Vectors of Viral Diseases

González

López

Rosell

et al. 2014

Natural Product Communications

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“…The location of methyl branches was described as: x‐Me, monomethyl alkanes; x,x‐DiMe, dimethyl alkanes; and x,x,x‐TriMe, trimethyl alkanes. Methyl branching assignments were based on their chromatographic retention index (KI) values and mass fragmentation patterns 32,34,35 …”

Section: Methodsmentioning

confidence: 99%

“…Methyl branching assignments were based on their chromatographic retention index (KI) values and mass fragmentation patterns. 32,34,35 Hydrocarbons were also analyzed by CGC coupled to a flame ionization detector, using helium as a mobile phase (2 ml min −1 ), and setting the flame ionization detector at 360°C. Extracts obtained from each subsample were dissolved in n-hexane (10 μl) and 1 μl was later injected into CGC.…”

Section: Sample Extraction and Hydrocarbon Purificationmentioning

confidence: 99%

Epicuticular hydrocarbons of the redbanded stink bug Piezodorus guildinii (Heteroptera: Pentatomidae): sexual dimorphism and alterations in insects collected in insecticide‐treated soybean crops

Sessa

Calderón-Fernández

Abreo

et al. 2021

Pest Management Science

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BACKGROUND The redbanded stink bug Piezodorus guildinii (Heteroptera: Pentatomidae) is one of the most important species affecting soybean crops in southern South America. Capillary gas chromatography coupled to mass spectrometry was used to characterize the epicuticular hydrocarbon profiles of field‐collected insects, and to identify differences in their composition between fifth‐instar nymphs and adults, males and females, and between bugs collected in insecticide‐treated and insecticide‐free soybean crops. RESULTS Straight chain saturated n‐C27 and n‐C29, and monomethyl and dimethyl chains of C31 and C33 were the most abundant compounds. A group of volatile hydrocarbons with n‐C13 and n‐C15 as the predominant compounds were also detected. The hydrocarbon pattern was different between nymphs and adults, either males or females. Heneicosene was almost exclusively detected in adult males and was the most important component to differentiate between both sexes, followed by tricosadiene. The total hydrocarbon amount was significantly higher in nymphs, males and females collected in insecticide‐treated fields compared with insects obtained from untreated fields. CONCLUSION Differences were found in the epicuticular hydrocarbon pattern among nymphs and adults, as well as sexual dimorphism in adult stink bugs. Interestingly, an alteration was also found in the hydrocarbon profile of insects collected in insecticide‐treated soybean crops and its relevance is discussed within a pest management context.

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“…As it turns out, the presence of even mass numbered fragments in the mass spectra of branched alkanes has a high diagnostic value because important information to interpret the spectrum and is instrumental in identifying the position of the internal methyl. Long chain, internally branched methylalkanes are characterized by the typical cleavage at the branched position and by a fragment at M-15, the molecular ion is often not being visible (Nelson et al 1972). But in 1968, a study on fragmentation patterns of saturated aliphatic hydrocarbon found that internally branched alkanes may undergo additional fragmentation pathways, for instance involving the equivalent of an hydrogen radical transfer (McCarthy et al 1968).…”

Section: Notesmentioning

confidence: 99%

Relevance of animal studies in the toxicological assessment of oil and wax hydrocarbons. Solving the puzzle for a new outlook in risk assessment

Carrillo

Danneels

Woldhuis³

2021

Critical Reviews in Toxicology

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Paraffin waxes and white mineral oils are distinct petroleum products separated from a common feedstock by crystallization, where only n-alkanes, iso-and cyclo-alkanes with a linear backbone of $ 20 carbon atoms long, selectively crystalize out from the oil to form the wax, which is solid at room temperature, whereas oils remain liquid. Up until the 90's, these differences were reflected in separated regulatory assessments. A paradigm shift occurred when Fischer 344 rats (F-344) developed liver epithelioid granuloma following exposure to low and medium viscosity oils or waxes. This lesion was used as common denominator between these products to be jointly assessed under the common term "mineral hydrocarbons -MHC", obviating compositional differences. This regulatory paradigm dominated for the next 30 years, exacerbated by the EFSA 2012 evaluation using the analytical term "MOSH" (mineral oil saturated hydrocarbons) which encompassed these products under single chromatography fraction. The reconstruction of historical developments, together with recent EFSA-sponsored studies of toxicity and accumulation and supporting literature, has allowed us to understand the etiology of the F-344 rat hepatic epithelioid granuloma, which is presented in an adverse outcome pathway (AOP). Considering chemical composition, it clearly demonstrates that the hepatic effects in F-344 rats caused by linear alkanes of waxes are irrelevant for humans. Waxes are thus not MOSH and should thus be evaluated on their own merit. The term MOSH should not include n-alkanes and be exclusively used to mineral oil fractions when considering their chemical makeup for a relevant human hazard assessment.

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Mass spectra of methyl-branched hydrocarbons from eggs of the tobacco hornworm

Cited by 107 publications

References 15 publications

Cuticular and Internal Chemical Composition of Biting Midges Culicoides spp. (Diptera: Ceratopogonidae), Potential Vectors of Viral Diseases

Cuticular and Internal Chemical Composition of Biting Midges Culicoides spp. (Diptera: Ceratopogonidae), Potential Vectors of Viral Diseases

Epicuticular hydrocarbons of the redbanded stink bug Piezodorus guildinii (Heteroptera: Pentatomidae): sexual dimorphism and alterations in insects collected in insecticide‐treated soybean crops

Relevance of animal studies in the toxicological assessment of oil and wax hydrocarbons. Solving the puzzle for a new outlook in risk assessment

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