scholarly journals Neglected Very Long-Chain Hydrocarbons and the Incorporation of Body Surface Area Metrics Reveal Novel Perspectives for Cuticular Profile Analysis in Insects

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 83
Author(s):  
Marek Golian ◽  
Tanja Bien ◽  
Sebastian Schmelzle ◽  
Margy Alejandra Esparza-Mora ◽  
Dino Peter McMahon ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chain Length ◽  
Body Surface ◽  
Profile Analysis ◽  
Analytical Techniques ◽  
Ionization Mass ◽  
Surface Areas ◽  
Length Range ◽  
A Chain ◽  
Long Chain

Most of our knowledge on insect cuticular hydrocarbons (CHCs) stems from analytical techniques based on gas-chromatography coupled with mass spectrometry (GC-MS). However, this method has its limits under standard conditions, particularly in detecting compounds beyond a chain length of around C40. Here, we compare the CHC chain length range detectable by GC-MS with the range assessed by silver-assisted laser desorption/ionization mass spectrometry (Ag-LDI-MS), a novel and rarely applied technique on insect CHCs, in seven species of the order Blattodea. For all tested species, we unveiled a considerable range of very long-chain CHCs up to C58, which are not detectable by standard GC-MS technology. This indicates that general studies on insect CHCs may frequently miss compounds in this range, and we encourage future studies to implement analytical techniques extending the conventionally accessed chain length range. Furthermore, we incorporate 3D scanned insect body surface areas as an additional factor for the comparative quantification of extracted CHC amounts between our study species. CHC quantity distributions differed considerably when adjusted for body surface areas as opposed to directly assessing extracted CHC amounts, suggesting that a more accurate evaluation of relative CHC quantities can be achieved by taking body surface areas into account.

Analysis of very long-chain fatty acids using electrospray ionization mass spectrometry

2003 ◽  
Vol 79 (3) ◽  
pp. 189-196 ◽  
Author(s):  
Fredoen Valianpour ◽  
Jacqueline J.M Selhorst ◽  
Lia E.M van Lint ◽  
Albert H van Gennip ◽  
Ronald J.A Wanders ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Long Chain Fatty Acids ◽  
Long Chain ◽  
Chain Fatty Acids

scholarly journals A straightforward electrospray ionization high resolution mass spectrometry method for underivatized long chain polysaccharides

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Roxana M. Ghiulai ◽  
Mirela Sarbu ◽  
Constantin Ilie ◽  
Alina D. Zamfir
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Electrospray Ionization ◽  
High Resolution Mass Spectrometry ◽  
Average Molecular Weight ◽  
Ionization Mass ◽  
Esi Ms ◽  
Singly Charged ◽  
Charged Ions ◽  
Long Chain

AbstractStructural analysis of long chain polysaccharides by electrospray ionization mass spectrometry (ESI-MS) is challenging since these molecules do not contain readily ionizable groups. Their mass spectra are dominated by singly charged ions, limiting the detection of high molecular weight species. Derivatization can enhance ionization, but analyte loss on purification decreases sensitivity. We report a method based on nanoESI-MS and MS/MS by collision induced dissociation (CID) for underivatized long chain polysaccharides. The procedure was tested on underivatized polydisperse dextrans (average molecular weight 4,000) at 2.6 kV ESI voltage and CID MS/MS at energies between 30-60 eV. 113 ions corresponding to species from Glc2 to Glc35 were detected. Ions at m/z 1,409.48, 1,107.35 and 1,438.47, assigned to [G17+2Na]2+,[G20+H+Na+K]3+ and [G35+2H+Na+K]4+, were sequenced and characterized by MS/MS. The component containing 35 Glc repeats is the longest polysaccharide chain detected by ESI-MS and structurally analyzed by MS/MS without prior derivatization and/or separation.

scholarly journals Determination of Semivolatile Organic Nitrates in Ambient Atmosphere by Gas Chromatography/Electron Ionization–Mass Spectrometry

Atmosphere ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 88 ◽  
Author(s):  
Rui Li ◽  
Xiaotong Jiang ◽  
Xinfeng Wang ◽  
Tianshu Chen ◽  
Lin Du ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Analytical Techniques ◽  
Electron Ionization ◽  
Electron Ionization Mass Spectrometry ◽  
Ionization Mass Spectrometry ◽  
Organic Nitrates ◽  
Ionization Mass ◽  
Ambient Atmosphere ◽  
Characteristic Fragment

Semivolatile organic nitrates (SVONs) contribute a large proportion of total organic nitrates and play an important role in the tropospheric chemistry. However, the composition and concentrations of SVONs in the atmosphere remain unclear due to the lack of reliable analytical techniques for specific organic nitrates. In this study, a method based on gas chromatography and electron ionization–mass spectrometry was developed to detect ambient SVONs that were collected via polyurethane foam disk enrichment. Three SVONs were identified in the semivolatile samples from urban Jinan during spring based on the characteristic fragment ions of [NO2]+ and [CH2NO3]+ and the characteristic fragment loss of NO2 and NO3: 1-pentyl nitrate (molecular weight [MW] = 133), 4-hydroxy-isoprene nitrate (MW = 147), and (3,4)-di-hydroxy-isoprene nitrate (MW = 163). The latter two isoprene nitrates were rarely detected in the real atmosphere in previous studies. The contents of 1-pentyl nitrate, 4-hydroxy-isoprene nitrate, and (3,4)-di-hydroxy-isoprene nitrate were roughly quantified based on the standard of 1-pentyl nitrate, with a detection limit of 50 μg L−1. In addition, Fourier transform infrared spectrometry was used to determine the total SVONs content. The average concentrations of 1-pentyl nitrate, 4-hydroxy-isoprene nitrate, (3,4)-di-hydroxy-isoprene nitrate, and total SVONs in Jinan during spring were 20.2 ± 7.2, 13.2 ± 7.2, 36.5 ± 8.4, and 380.0 ± 190.8 ng m−3, respectively. The three identified SVONs contributed only 20.2 ± 5.5% to the total SVONs, which suggests that some unidentified SVONs are present in the ambient atmosphere and that studies with improved or advanced analytical techniques will be required to identify them.

The Chlorine Atom Sensitized Oxidation and the Ozonolysis of C2Cl4

1974 ◽  
Vol 52 (23) ◽  
pp. 3852-3862 ◽  
Author(s):  
Eckart Mathias ◽  
Eugenio Sanhueza ◽  
I. C. Hisatsune ◽  
Julian Heicklen
Keyword(s):  
Free Radicals ◽  
Chain Length ◽  
Chlorine Atom ◽  
Chain Process ◽  
Chain Mechanism ◽  
A Chain ◽  
A Minor ◽  
Long Chain

The chlorine atom initiated oxidation of C2Cl4 was studied both in the absence and presence of O3 at 24 and 32 °C. In the absence of O3, the products are CCl3CCl(O) and CCl2O, and they are produced in a long-chain process in a ratio of 2.5 at 24 °C and 3.0 at 32 °C. The product producing step involves the decay of C2Cl5O radicals[Formula: see text]The ratio k6a/k6b is 5.0 at 24 °C and 6.0 at 32 °C since CCl3 reacts with O2 to produce another CCl2O molecule. In the presence of O3 the ratio Φ{CCl3CCl(O)}/Φ{CCl2O} drops, [Formula: see text] is produced, and the chain length is reduced. The change in Φ{CCl3CCl(O)}/Φ{CCl2O} is a function of [O3]/[O2] and is attributed to the additional reactions[Formula: see text]The epoxide yield is a function of [C2Cl4]/[O3] and is attributed to the reaction of ClO with C2Cl4. The ClO is produced by the reaction of Cl• with O3[Formula: see text]which competes with[Formula: see text]The ratio k2/kl0 = 6.7. The reduction in yield as O3 is added results from the terminating reaction[Formula: see text]The ClO2 reacts further with O3 to produce Cl2O7.The reaction of O3 with C2Cl4 at 24 °C also produces mainly CCl3CCl(O) and CCl2O with [Formula: see text] as a minor product. Other minor products detected after extended conversions included Cl2, CO, and CO2. However c-C3Cl6 was not found. The ratio [CCl3CCl(O)]/[CCl2O] is < 1. Moreover, the addition of O2 retarded the reaction, indicating a long chain mechanism in which both free radicals (species with an odd number of electrons) and CCl2 were absent. A diradical chain mechanism is presented which explains the main features. The chain step is the addition of CCl2O2 to C2Cl4[Formula: see text]The adduct then reacts with O3 in a chain regenerating step or with O2 in a chain terminating step.

scholarly journals Identification of some Neutral Lipids of Thiobacillus Thioparus Using Gas Chromatography-Chemical Ionization Mass Spectrometry

1980 ◽  
Vol 33 (6) ◽  
pp. 737 ◽  
Author(s):  
RK Christopher ◽  
AM Duffield ◽  
BJ Ralph
Keyword(s):  
Mass Spectrometry ◽  
Chemical Ionization ◽  
Neutral Lipids ◽  
Lipid Fraction ◽  
Ethyl Esters ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Thiobacillus Thioparus ◽  
Long Chain

The neutral lipid fraction of two strains of T. thioparus was examined using gas chromatographychemical ionization mass spectrometry. Both strains were found to produce fatty acid ethyl esters, long-chain alcohols and. wax esters. In addition, one strain produced substantial quantities of squalene, although no sterols or triterpenoids could be detected. However, in the second strain, although squalene was present at greatly reduced levels, cholesterol, lanosteryl acetate and 24,25-dihydrolanosteryl acetate were identified.

Regulation of leptin secretion from white adipocytes by free fatty acids

2003 ◽  
Vol 285 (3) ◽  
pp. E521-E526 ◽  
Author(s):  
Philippe G. Cammisotto ◽  
Yves Gélinas ◽  
Yves Deshaies ◽  
Ludwik J. Bukowiecki
Keyword(s):  
Fatty Acids ◽  
Chain Length ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Acid Oxidation ◽  
Mitochondrial Fatty Acid Oxidation ◽  
White Adipocytes ◽  
Mitochondrial Fatty Acid ◽  
A Chain ◽  
Long Chain

Norepinephrine stimulates lipolysis and concurrently inhibits insulin-stimulated leptin secretion from white adipocytes. To assess whether there is a cause-effect relationship between these two metabolic events, the effects of fatty acids were investigated in isolated rat adipocytes incubated in buffer containing low (0.1%) and high (4%) albumin concentrations. Palmitic acid (1 mM) mimicked the inhibitory effects of norepinephrine (1 μM) on insulin (10 nM)-stimulated leptin secretion, but only at low albumin concentrations. Studies investigating the effects of the chain length of saturated fatty acids [from butyric (C4) to stearic (C18) acids] revealed that only fatty acids with a chain length superior or equal to eight carbons effectively inhibited insulin-stimulated leptin secretion. Long-chain mono- and polyunsaturated fatty acids constitutively present in adipocyte triglyceride stores (oleic, linoleic, γ-linolenic, palmitoleic, eicosapentanoic, and docosahexanoic acids) also completely suppressed leptin secretion. Saturated and unsaturated fatty acids inhibited insulin-stimulated leptin secretion with the same potency and without any significant effect on basal secretion. On the other hand, inhibitors of mitochondrial fatty acid oxidation (palmoxirate, 2-bromopalmitate, 2-bromocaproate) attenuated the stimulatory effects of insulin on leptin release without reversing the effects of fatty acids or norepinephrine, suggesting that fatty acids do not need to be oxidized by the mitochondria to inhibit leptin release. These results demonstrate that long-chain fatty acids mimic the effects of norepinephrine on leptin secretion and suggest that they may play a regulatory role as messengers between stimulation of lipolysis by norepinephrine and inhibition of leptin secretion.

scholarly journals Formation of 3-methyl-1,2,3-butanetricarboxylic acid via gas phase oxidation of pinonic acid – a mass spectrometric study of SOA aging

2012 ◽  
Vol 12 (3) ◽  
pp. 1483-1496 ◽  
Author(s):  
L. Müller ◽  
M.-C. Reinnig ◽  
K. H. Naumann ◽  
H. Saathoff ◽  
T. F. Mentel ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Atmospheric Pressure Chemical Ionization ◽  
Analytical Techniques ◽  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Oxidation Products ◽  
Acid Oxidation ◽  
Ionization Mass ◽  
Institute Of Technology

Abstract. This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS). The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a very low volatile α-pinene SOA product and a tracer compound for terpene SOA, is formed from the oxidation of pinonic acid and that this oxidation takes place in the gas phase. This finding is confirmed by temperature-dependent aging experiments on whole SOA formed from α-pinene, in which the yield of MBTCA scales with the pinonic acid fraction in the gas phase. Based on the results, several feasible gas-phase radical mechanisms are discussed to explain the formation of MBTCA from OH-initiated pinonic acid oxidation.

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