Статті в журналах: "Long-chain n-alkanes"

1

Thontowi, Ahmad, Elvi Yetti, and Yopi Yopi. "Medium Chain and Long Chain Alkanes Hydroxylase Producing Whole Cell Biocatalyst From Marine Bacteria." ANNALES BOGORIENSES 22, no. 1 (September 10, 2018): 12. http://dx.doi.org/10.14203/ab.v22i1.329.

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Alkanes are major component of crude oil that could be hydrolyzed by the enzyme of alkane hydroxylase. The are three types of alkane hydroxylase based on the chain length of alkane such as short-chain length/SCL (C2-C4), medium-chain length/MCL (C5-C17), and long-chain length/LCL (C>18). The aims of this study were to characterize and identify alkanes-degrading bacteria from these bacteria. The 30 strains from marine were grown on MCL (Pentane-C5H12, Decane-C10H22, and Pentadecane-C15H32) and LCL (n-Paraffin-C12H19C17 and branch of Pristane-C19H40). The study showed twenty-nine isolates have the ability to degrade alkanes compounds, whereas 14 isolates have grown ability on MCL and LCL medium, 11 isolates have the ability to grow on MCL and n-LCL, 3 isolates have the ability only to grow on MCL medium and 1 isolate has the ability only grow on n-LCL medium. The growth test result indicated that 29 isolates have medium-chain alkane monooxygenase and long-chain alkane hydroxylase. Based on 16S rDNA gene analysis, we obtained twenty nine of oil- degrading bacteria, namely a-proteobacteria (57 %), g-proteobacteria (30 %), Flavobacteria (7 %), Bacilli (3%) and Propionibacteriales (3 %). g-Proteobacteria and a-proteobacteria which seems to play an important role in the alkane biodegradation.

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2

Thontowi, Ahmad, Elvi Yetti, and Yopi Yopi. "Medium Chain and Long Chain Alkanes Hydroxylase Producing Whole Cell Biocatalyst From Marine Bacteria." ANNALES BOGORIENSES 22, no. 1 (June 29, 2018): 12. http://dx.doi.org/10.14203/ann.bogor.2018.v22.n1.12-19.

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Alkanes are major component of crude oil that could be hydrolyzed by the enzyme of alkane hydroxylase. The are three types of alkane hydroxylase based on the chain length of alkane such as short-chain length/SCL (C2-C4), medium-chain length/MCL (C5-C17), and long-chain length/LCL (C>18). The aims of this study were to characterize and identify alkanes-degrading bacteria from these bacteria. The 30 strains from marine were grown on MCL (Pentane-C5H12, Decane-C10H22, and Pentadecane-C15H32) and LCL (n-Paraffin-C12H19C17 and branch of Pristane-C19H40). The study showed twenty-nine isolates have the ability to degrade alkanes compounds, whereas 14 isolates have grown ability on MCL and LCL medium, 11 isolates have the ability to grow on MCL and n-LCL, 3 isolates have the ability only to grow on MCL medium and 1 isolate has the ability only grow on n-LCL medium. The growth test result indicated that 29 isolates have medium-chain alkane monooxygenase and long-chain alkane hydroxylase. Based on 16S rDNA gene analysis, we obtained twenty nine of oil- degrading bacteria, namely a-proteobacteria (57 %), g-proteobacteria (30 %), Flavobacteria (7 %), Bacilli (3%) and Propionibacteriales (3 %). g-Proteobacteria and a-proteobacteria which seems to play an important role in the alkane biodegradation.

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3

Throne-Holst, Mimmi, Alexander Wentzel, Trond E. Ellingsen, Hans-Kristian Kotlar, and Sergey B. Zotchev. "Identification of Novel Genes Involved in Long-Chain n-Alkane Degradation by Acinetobacter sp. Strain DSM 17874." Applied and Environmental Microbiology 73, no. 10 (March 30, 2007): 3327–32. http://dx.doi.org/10.1128/aem.00064-07.

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ABSTRACT Acinetobacter sp. strain DSM 17874 is capable of utilizing n-alkanes with chain lengths ranging from that of decane (C10H22) to that of tetracontane (C40H82) as a sole carbon source. Two genes encoding AlkB-type alkane hydroxylase homologues, designated alkMa and alkMb, have been shown to be involved in the degradation of n-alkanes with chain lengths of from 10 to 20 C atoms in this strain. Here, we describe a novel high-throughput screening method and the screening of a transposon mutant library to identify genes involved in the degradation of n-alkanes with C chain lengths longer than 20, which are solid at 30°C, the optimal growth temperature for Acinetobacter sp. strain DSM 17874. A library consisting of approximately 6,800 Acinetobacter sp. strain DSM 17874 transposon mutants was constructed and screened for mutants unable to grow on dotriacontane (C32H66) while simultaneously showing wild-type growth characteristics on shorter-chain n-alkanes. For 23 such mutants isolated, the genes inactivated by transposon insertion were identified. Targeted inactivation and complementation studies of one of these genes, designated almA and encoding a putative flavin-binding monooxygenase, confirmed its involvement in the strain's metabolism of long-chain n-alkanes. To our knowledge, almA represents the first cloned gene shown to be involved in the bacterial degradation of long-chain n-alkanes of 32 C's and longer. Genes encoding AlmA homologues were also identified in other long-chain n-alkane-degrading Acinetobacter strains.

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4

Mayes, R. V., I. A. Wright, C. S. Lamb, and Alison McBean. "The use of long-chain n-alkanes for estimating intake and digestibility of herbage in cattle." Proceedings of the British Society of Animal Production (1972) 1986 (March 1986): 83. http://dx.doi.org/10.1017/s0308229600015920.

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Studies with sheep suggest that accurate estimates of herbage intake can be obtained by using the herbage alkane tritriacontane (C33) and dosed dotriacontane (C32) as markers, since the faecal recoveries of both alkanes have been shown to be very similar. To validate the technique for herbage intake estimation in grazing cattle there is a need to compare in cattle, the faecal recoveries of both herbage and dosed n-alkanes. It has been observed in sheep that the faecal recoveries of n-alkanes increase as their chain lengths increase, suggesting that the recovery of hexatriacontane (C36), an alkane absent from herbage but available commercially at low cost, should be complete. C36 may therefore have potential as a dosed marker for estimation of faecal output. Thus it may .30 be possible to obtain estimates of both herbage intake and diet digestibility in the same individual grazing animal using n-alkanes as markers. The purpose of the experiment described here was to determine the faecal recoveries in cattle of odd-chain n-alkanes from fresh herbage and of C32 and C36 dosed n-alkanes.

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5

Bliedtner, Marcel, Imke K. Schäfer, Roland Zech, and Hans von Suchodoletz. "Leaf wax n-alkanes in modern plants and topsoils from eastern Georgia (Caucasus) – implications for reconstructing regional paleovegetation." Biogeosciences 15, no. 12 (June 29, 2018): 3927–36. http://dx.doi.org/10.5194/bg-15-3927-2018.

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Abstract. Long-chain n-alkanes originate from leaf waxes of higher terrestrial plants, they are relatively resistant against physical and chemical degradation and are preserved in sediment archives for at least millennial timescales. Since their homologue patterns discriminate between vegetation forms, they were increasingly used for paleovegetation reconstructions during the last years. However, before any robust interpretation of the long-chain n-alkane patterns in sediment archives, reference samples from modern vegetation and topsoil material should be investigated at a regional scale. Apart from some temperate and tropical regions, such systematic regional studies on modern plant and topsoil material are still largely lacking.To test the potential of leaf wax-derived n-alkane patterns for paleoenvironmental studies in the semi-humid to semi-arid central southern Caucasus region, we investigated the influence of different vegetation forms on the leaf wax n-alkane signal in modern plants and topsoil material (0–5 cm) from eastern Georgia. We sampled (i) sites with grassland/herbs that included steppe, cultivated grassland and meadows, and (ii) sites that are dominated by deciduous hornbeam forests.The results show that long-chain n-alkanes originate from leaf waxes of higher terrestrial plants and that their homologue pattern allow to discriminate between different vegetation forms: n-Alkanes derived from sites with grassland/herbs are mainly dominated by C31, while n-alkanes derived from sites with deciduous trees/shrubs show high abundances of C29. Thus, long-chain n-alkanes have a great potential when used for regional paleovegetation reconstructions. Moreover, the n-alkane distributions of the topsoils do not show correlations with mean annual temperatures and precipitation along the investigated transect. As degradation of organic matter can affect the leaf wax n-alkane distribution, we further present an updated end-member model that includes our results, accounts for degradation effects and enables semi-quantitative reconstructions of past vegetation changes in the central southern Caucasus region.

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Carnahan, A. M., D. E. Spalinger, and W. B. Collins. "n-Alkane and long-chain alcohol recovery in moose (Alces alces), a browsing herbivore." Canadian Journal of Zoology 96, no. 6 (June 2018): 559–65. http://dx.doi.org/10.1139/cjz-2017-0131.

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Habitat management for herbivores often depends on an understanding of the food habits of animals. Plant cuticular waxes containing nearly indigestible complex mixture of n-alkanes and long-chain alcohols (LCOHs) have recently shown promise for diet analyses, but the accuracy of the technique depends strongly on the efficiency of recovery of the markers in feces. Fecal recovery of n-alkanes and LCOHs from 10 browse stems or leaves and two ensiled grass hays fed to moose (Alces alces (Linnaeus, 1758)) during in vivo digestion trials was investigated. n-Alkanes and LCOHs were extracted using a single-step accelerated solvent extraction technique and the recovery of these cuticular components was calculated from the feces of the animals. n-Alkane recoveries from feces averaged 0.82, ranging from a low of 0.58 (haylage) to a high of 0.95 (browse stems). LCOH recoveries averaged 0.92 across all forages, ranging from 0.80 (haylage) to a high of 1.13 (browse stems). n-Alkane and LCOH fecal recovery increased with increasing chain length, similar to findings in other studies. Although fecal recovery of n-alkanes and LCOHs were variable, we conclude that they are inversely related to forage digestibility, are consistent within forage classes, and are therefore predictable markers for use in assessing herbivore diets.

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7

Tani, Akio, Takeru Ishige, Yasuyoshi Sakai, and Nobuo Kato. "Gene Structures and Regulation of the Alkane Hydroxylase Complex in Acinetobacter sp. Strain M-1." Journal of Bacteriology 183, no. 5 (March 1, 2001): 1819–23. http://dx.doi.org/10.1128/jb.183.5.1819-1823.2001.

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ABSTRACT In the long-chain n-alkane degraderAcinetobacter sp. strain M-1, two alkane hydroxylase complexes are switched by controlling the expression of twon-alkane hydroxylase-encoding genes in response to the chain length of n-alkanes, while rubredoxin and rubredoxin ruductase are encoded by a single gene and expressed constitutively.

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8

Kong, Weina, Cheng Zhao, Xingwang Gao, Liping Wang, Qianqian Tian, Yu Liu, Shuwen Xue, Zhuang Han, Fulin Chen, and Shiwei Wang. "Characterization and Transcriptome Analysis of a Long-Chain n-Alkane-Degrading Strain Acinetobacter Pittii SW-1." International Journal of Environmental Research and Public Health 18, no. 12 (June 11, 2021): 6365. http://dx.doi.org/10.3390/ijerph18126365.

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Strain sw-1, isolated from 7619-m seawater of the Mariana Trench, was identified as Acinetobacter pittii by 16S rRNA gene and whole-genome sequencing. A. pittii sw-1 was able to efficiently utilize long-chain n-alkanes (C18–C36), but not short- and medium-chain n-alkanes (C8–C16). The degradation rate of C20 was 91.25%, followed by C18, C22, C24, C32, and C36 with the degradation rates of 89.30%, 84.03%, 80.29%, 30.29%, and 13.37%, respectively. To investigate the degradation mechanisms of n-alkanes for this strain, the genome and the transcriptome analyses were performed. Four key alkane hydroxylase genes (alkB, almA, ladA1, and ladA2) were identified in the genome. Transcriptomes of strain sw-1 grown in C20 or CH3COONa (NaAc) as the sole carbon source were compared. The transcriptional levels of alkB and almA, respectively, increased 78.28- and 3.51-fold in C20 compared with NaAc, while ladA1 and ladA2 did not show obvious change. The expression levels of other genes involved in the synthesis of unsaturated fatty acids, permeases, membrane proteins, and sulfur metabolism were also upregulated, and they might be involved in n-alkane uptake. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) confirmed that alkB expression was significantly induced by C20, C24, and C32, and almA induction extent by C24 and C32 was higher than that with C20. Furthermore, ladA2 expression was only induced by C32, and ladA1 expression was not induced by any of n-alkanes. In addition, A. pittii sw-1 could grow with 0%–3% NaCl or 8 out of 10 kinds of the tested heavy metals and degrade n-alkanes at 15 °C. Taken together, these results provide comprehensive insights into the degradation of long-chain n-alkanes by Acinetobacter isolated from the deep ocean environment.

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9

McLean, B. M. L., R. W. Mayes, and F. D. DeB Hovell. "The Use of N-alkanes for Estimating Intake and Passage Rate in Horses." Proceedings of the British Society of Animal Science 1996 (March 1996): 98. http://dx.doi.org/10.1017/s1752756200592977.

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Alkanes occur naturally in all plants, although forage crops tend to have higher alkane contents than cereals. N-alkanes have odd-numbered carbon chains. They are ideal for use as markers in feed trials, because, they are inert, indigestible and naturally occurring, and can be recovered in animal faeces. Synthetic alkanes (even-numbered carbon chains) are available commercially and can also used as external markers. Dove and Mayes (1991) cite evidence indicating that faecal recovery of alkanes in ruminants increases with increasing carbon-chain length. Thus the alkane “pairs” (e.g. C35 & C36, and C32 & C33) are used in calculating intake and digestibility because they are long chain and adjacent to each other. However, recent work by Cuddeford and Mayes (unpublished) has found that in horses the faecal recovery rates are similar regardless of chain lengths.

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McLean, B. M. L., R. W. Mayes, and F. D. DeB Hovell. "The Use of N-alkanes for Estimating Intake and Passage Rate in Horses." Proceedings of the British Society of Animal Science 1996 (March 1996): 98. http://dx.doi.org/10.1017/s0308229600030683.

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Alkanes occur naturally in all plants, although forage crops tend to have higher alkane contents than cereals. N-alkanes have odd-numbered carbon chains. They are ideal for use as markers in feed trials, because, they are inert, indigestible and naturally occurring, and can be recovered in animal faeces. Synthetic alkanes (even-numbered carbon chains) are available commercially and can also used as external markers. Dove and Mayes (1991) cite evidence indicating that faecal recovery of alkanes in ruminants increases with increasing carbon-chain length. Thus the alkane “pairs” (e.g. C35 & C36, and C32 & C33) are used in calculating intake and digestibility because they are long chain and adjacent to each other. However, recent work by Cuddeford and Mayes (unpublished) has found that in horses the faecal recovery rates are similar regardless of chain lengths.

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11

Wentzel, Alexander, Trond E. Ellingsen, Hans-Kristian Kotlar, Sergey B. Zotchev, and Mimmi Throne-Holst. "Bacterial metabolism of long-chain n-alkanes." Applied Microbiology and Biotechnology 76, no. 6 (August 3, 2007): 1209–21. http://dx.doi.org/10.1007/s00253-007-1119-1.

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12

Schäfer, Imke K., Verena Lanny, Jörg Franke, Timothy I. Eglinton, Michael Zech, Barbora Vysloužilová, and Roland Zech. "Leaf waxes in litter and topsoils along a European transect." SOIL 2, no. 4 (October 25, 2016): 551–64. http://dx.doi.org/10.5194/soil-2-551-2016.

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Abstract. Lipid biomarkers are increasingly used to reconstruct past environmental and climate conditions. Leaf-wax-derived long-chain n-alkanes and n-alkanoic acids may have great potential for reconstructing past changes in vegetation, but the factors that affect the leaf wax distribution in fresh plant material, as well as in soils and sediments, are not yet fully understood and need further research. We systematically investigated the influence of vegetation and soil depth on leaf waxes in litter and topsoils along a European transect. The deciduous forest sites are often dominated by the n-C27 alkane and n-C28 alkanoic acid. Conifers produce few n-alkanes but show high abundances of the C24 n-alkanoic acid. Grasslands are characterized by relatively high amounts of C31 and C33 n-alkanes and C32 and C34 n-alkanoic acids. Chain length ratios thus may allow for distinguishing between different vegetation types, but caution must be exercised given the large species-specific variability in chain length patterns. An updated endmember model with the new n-alkane ratio (n-C31 + n-C33) / (n-C27 + n-C31 + n-C33) is provided to illustrate, and tentatively account for, degradation effects on n-alkanes.

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Yu, Yunlong, Yuanyuan Li, Zhigang Guo, and Hua Zou. "Distribution and sources of n-alkanes in surface sediments of Taihu Lake, China." Archives of Environmental Protection 42, no. 1 (March 1, 2016): 49–55. http://dx.doi.org/10.1515/aep-2016-0006.

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Abstract The last study on n-alkanes in surface sediments of Taihu Lake was in 2000, only 13 surface sediment samples were analysed, in order to have a comprehensive and up-to-date understanding of n-alkanes in the surface sediments of Taihu Lake, 41 surface sediment samples were analyzed by GC-MS. C10 to C37 were detected, the total concentrations of n-alkanes ranged from 2109 ng g−1 to 9096 ng g−1 (dry weight). There was strong odd carbon predominance in long chain n-alkanes and even carbon predominance in short chain n-alkanes. When this finding was combined with the analysis results of wax n-alkanes (WaxCn), carbon preference index (CPI), unresolved complex mixture (UCM), hopanes and steranes, it was considered that the long chain n-alkanes were mainly from terrigenous higher plants, and that the short chain n-alkanes mainly originated from bacteria and algae in the lake, compared with previous studies, there were no obvious anthropogenic petrogenic inputs. Terrestrial and aquatic hydrocarbons ratio (TAR) and C21−/C25+ indicated that terrigenous input was higher than aquatic sources and the nearshore n-alkanes were mainly from land-derived sources. Moreover, the distribution of short chain n-alkanes presented a relatively uniform pattern, while the long chain n-alkanes presented a trend that concentrations dropped from nearshore places to the middle of lake.

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Li, Zhuolun, Youhong Gao, and Lang Han. "Holocene vegetation signals in the Alashan Desert of northwest China revealed by lipid molecular proxies from calcareous root tubes." Quaternary Research 88, no. 1 (June 29, 2017): 60–70. http://dx.doi.org/10.1017/qua.2017.33.

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AbstractIn the hinterland of deserts, it is difficult to reconstruct paleovegetation using fossil pollen because of the low pollen concentration. Therefore, an efficient method is needed to reconstruct the paleovegetation of desert regions. In this study, 34 Holocene calcareous root tube (CRT) samples were collected from the Alashan Desert in northwest China, and lipid molecular proxies from CRTs were selected to address this deficiency. The results show that n-alkanes mainly maximized at C27, C29, and C16, and that the carbon preference index is close to 1. Thus, the sources of n-alkanes from CRTs were the roots of higher plants and microorganisms, and thus changes in n-alkanes from CRTs could reveal variations in vegetation cover. The n-alkane Cmax of long-chain n-alkanes (C>25) in CRTs, maximizing at C27, indicated that vegetation in the Alashan Desert was characterized by shrub vegetation during the Holocene. Changes in the ratio of (C27+C29)/(C31+C33) indicated that the biomass of shrub vegetation increased during the period 7–2 cal ka BP. Moreover, the relative concentration of short-chain to long-chain n-alkanes decreased from 7 to 2 cal ka BP, suggesting that the effective moisture decreased during that period.

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Park, Myong-Ok. "New Pathway for Long-Chain n-Alkane Synthesis via 1-Alcohol in Vibrio furnissii M1." Journal of Bacteriology 187, no. 4 (February 15, 2005): 1426–29. http://dx.doi.org/10.1128/jb.187.4.1426-1429.2005.

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ABSTRACT Alkane biosynthesis in the bacterium Vibrio furnissii M1 involves the synthesis of long-chain alkanes via 1-alcohol. Evidence for this novel pathway are the following. (i) Both even- and odd-carbon-number n-alkanes were produced from glucose, while only even-carbon-number fatty acids were produced in V. furnissii M1. This result cannot be explained by the decarbonylation pathway. (ii) Pentadecane and hexadecane were produced from 1-hexadecanoic acid by membrane fractions of V. furnissii M1, and radioisotope precursor-tracer experiments, in which 1-[1-14C]hexadecanoic acid was fed, identified the corresponding alcohol, aldehyde, and alkane derivatives. Since all metabolites maintained the radioisotope label at 1-C, they were produced by a pathway in which the carbon structure was retained, i.e., a reduction pathway. (iii) n-Hexadecane was produced when 1-hexadecanol was fed to membrane preparations.

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Erickson, M. H., H. W. Wallace, and B. T. Jobson. "Quantification of diesel exhaust gas phase organics by a thermal desorption proton transfer reaction mass spectrometer." Atmospheric Chemistry and Physics Discussions 12, no. 2 (February 20, 2012): 5389–423. http://dx.doi.org/10.5194/acpd-12-5389-2012.

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Abstract. A new approach was developed to measure the total abundance of long chain alkanes (C12 and above) in urban air using thermal desorption with a proton transfer reaction mass spectrometer (PTR-MS). These species are emitted in diesel exhaust and may be important precursors to secondary organic aerosol production in urban areas. Long chain alkanes undergo dissociative proton transfer reactions forming a series of fragment ions with formula CnH2n+1. The yield of the fragment ions is a function of drift conditions. At a drift field strength of 80 Townsends, the most abundant ion fragments from C10 to C16 n-alkanes were m/z 57, 71 and 85. The PTR-MS is insensitive to n-alkanes less than C8 but displays an increasing sensitivity for larger alkanes. Higher drift field strengths yield greater normalized sensitivity implying that the proton affinity of the long chain n-alkanes is less than H2O. Analysis of diesel fuel shows the mass spectrum was dominated by alkanes (CnH2n+1), monocyclic aromatics, and an ion group with formula CnH2n−1 (m/z 97, 111, 125, 139). The PTR-MS was deployed in Sacramento, CA during the Carbonaceous Aerosols and Radiative Effects Study field experiment in June 2010. The ratio of the m/z 97 to 85 ion intensities in ambient air matched that found in diesel fuel. Total diesel exhaust alkane concentrations calculated from the measured abundance of m/z 85 ranged from the method detection limit of ~1 μg m−3 to 100 μg m−3 in several air pollution episodes. The total diesel exhaust alkane concentration determined by this method was on average a factor of 10 greater than the sum of alkylbenzenes associated with spark ignition vehicle exhaust.

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Eslami, Hossein. "Equation of state for long-chain n-alkanes." Fluid Phase Equilibria 169, no. 1 (March 2000): 19–30. http://dx.doi.org/10.1016/s0378-3812(99)00331-3.

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Hayes, R. V., C. S. Lamb, and Patricia M. Colgrove. "Determination of herbage intake of suckling lambs using long-chain n-alkanes as markers." Proceedings of the British Society of Animal Production (1972) 1986 (March 1986): 82. http://dx.doi.org/10.1017/s0308229600015919.

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The n-alkanes of grass outioular wax (odd-chain, C25- C25) can be used simultaneously with dosed n-alkanes (C28or C32) as markers for estimating the herbage intake of grazing sheep if the faecal recoveries of both herbage and dosed markers are the same. In adult sheep the accuracy of herbage intake estimation is not affected by the inclusion of concentrate in the diet as long as the intake and alkane concentrations of the concentrate are known. If, similarly, the ingestion of milk does not interfere with the relative absorption of dosed and herbage alkanes the herbage intake of suckling lambs at pasture could be estimated. To evaluate the potential of the technique in suckling lambs the faecal recoveries of odd-chain herbage n-alkanes and of dosed dotriacontane (C32) were determined in lambs offered eves’ milk and freshly cut herbage.From 2 weeks of age seven individually-housed male lambs received 1 kg/day homogenised ewes’ milk (166 g/day dry matter (DM)) in 4 feeds from an automatic feeder. The milk Has obtained by daily hand-milking of East Friesland ewes and was stored at -20° until used. Freshly cut perennial ryegrass was offered to the lambs ad libitum from the age of 4 weeks. A 6-day total collection of faeces was carried out when the lamba were 10 weeks of age.

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Struck, Julian, Marcel Bliedtner, Paul Strobel, Jens Schumacher, Enkhtuya Bazarradnaa та Roland Zech. "Leaf wax n-alkane patterns and compound-specific δ13C of plants and topsoils from semi-arid and arid Mongolia". Biogeosciences 17, № 3 (5 лютого 2020): 567–80. http://dx.doi.org/10.5194/bg-17-567-2020.

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Abstract. Leaf wax n-alkane patterns and their compound-specific δ13C signatures are valuable proxies for paleoenvironmental reconstructions. So far, their potential has not been investigated in semi-arid to arid Mongolia. We have therefore analysed the leaf wax n-alkanes and their compound-specific δ13C signature of five plant species (Poaceae, Cyperaceae, Artemisia spp., Caragana spp. and Larix sp.) and topsoils (0–5 cm) along two transects in central and southern Mongolia. Grasses show a distinct dominance of the n-C31 homologue, whereas the shrubs Caragana spp. and Artemisia spp. are dominated by n-C29. Larix sp. is characterised by the mid-chain n-alkanes n-C23 and n-C25. From plant to topsoil, n-alkane patterns show the potential to differentiate between grass-covered sites from those covered by Caragana spp. n-Alkane concentrations and odd-over-even predominance (OEP) of the topsoils are distinctly influenced by mean annual temperature, mean annual precipitation and aridity, likely reflecting the degree of n-alkane degradation and biomass production. In contrast, the average chain length (ACL) and the n-alkane ratio (n-C31∕n-C29+n-C31) are not affected by climatic parameters and, thus, are not biased by climate. The compound-specific δ13C signatures are strongly correlated to climate, showing a significant enrichment with increasing aridity, indicating the effect of water use efficiency. Our calibration results suggest that long-chain n-alkanes and their compound-specific δ13C signatures have great potential to reconstruct paleoenvironmental and paleoclimatic conditions when used in sediment archives from Mongolia.

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Bugalho, Miguel N., John A. Milne, Robert W. Mayes, and Francisco C. Rego. "Plant-wax alkanes as seasonal markers of red deer dietary components." Canadian Journal of Zoology 83, no. 3 (March 1, 2005): 465–73. http://dx.doi.org/10.1139/z05-031.

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n-Alkanes are long-chain hydrocarbons commonly occurring in plant cuticles that can be recovered in herbivore faeces. Differences among plant species in their content of cuticular wax n-alkanes can be exploited to estimate diet composition of herbivores. n-Alkanes have been used mainly in domesticated herbivores feeding on relatively simple diets over short-term periods. Extending the method to wild herbivores feeding on seasonal complex diets is possible provided that n-alkanes act as effective dietary component markers in different seasons. The n-alkane content of browse species and herbage layer and of faeces of red deer (Cervus elaphus L., 1758) males and females in a region with a Mediterranean climate is described. Information on the n-alkane content of plant species was related to that of faeces to estimate the diet composition of red deer. Plant species had distinct n-alkane contents, some of which varied seasonally. The n-alkane content of faeces also varied seasonally and between red deer sexes. Both red deer males and females had relatively high proportion of browse in their diets during summer and of herbage layer in spring, as shown by other studies in Mediterranean environments.

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Nikolić, Biljana, Marina Todosijević, Iris Đorđević, Jovana Stanković, Zorica S. Mitić, Vele Tešević, and Petar D. Marin. "Nonacosan-10-ol and n-Alkanes in Leaves of Pinus pinaster." Natural Product Communications 15, no. 5 (May 2020): 1934578X2092607. http://dx.doi.org/10.1177/1934578x20926073.

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In leaf cuticular wax of Pinus pinaster, content of nonacosan-10-ol is high (77.1% on average). n-Alkanes ranged from C18 to C35 with the most dominant C29 (24.8%). The carbon preference index (CPItotal) ranged from 3.1 to 5.6 (4.0 on average), while the average chain length (ACLtotal) ranged from 14.0 to 17.0 (14.8 on average). Long-chain n-alkanes ( n-C25-35) strongly dominated (80.1%) over middle-chain ( n-C21-24 = 18.9%) and short-chain ( n -C18-20 = 0.9%) n-alkanes.

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Grilo, Caroline Fiório, Eduardo Schettini Costa, Renato Rodrigues Neto, George Wolff, and Anu Thompson. "Exchange between macrophyte and mangrove organic matter input in estuarine systems: drought implications." Revista Ibero-Americana de Ciências Ambientais 9, no. 4 (May 23, 2018): 83–98. http://dx.doi.org/10.6008/cbpc2179-6858.2018.004.0007.

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Paq proxy was applied on mid and long-chain n-alkanes in order to develop an index to assist in the long-term assessment of changes and exchanges between aquatic communities in estuarine environments as a result of increased saline incursion. New boundaries are proposed according to n-alkanes abundance in the leaves of local mangrove tree species for better definition of emergent aquatic plant end-member. Molecular distribution and δ13C isotopic signatures of n-alkanes were also used to support the parameter. A predominance of odd carbon-numbered long chain (> C27 n-alkanes) indicated a main terrestrial input, although mid-chain n-alkanes (23 and 25 carbons) were also identified. Short-chain n-alkanes (< 19) were absent or found in a very small concentration. Carbon Preference Index and C/N ratio reinforced a terrestrial origin for the sedimentary organic matter. δ13C signatures of n-alkanes for C23, C25, C29 and C31 were characteristic of mangrove input, ranging from -27.57 ‰ (C23) to -34.40 ‰ (C29) for Piraquê-Mirim River (PM) and from -27.36 ‰ (C23) to -32.84 ‰ (C31) for Piraquê-Açu River (PA) without any particular trend. Paq proxy was successfully used to identify rises in marine macrophytes (mid-chain n-alkanes) input mainly in the confluence and PM probably as consequence of drought periods. The confluence presented a mixing sources of OM. PA was identified as a stable mangrove environment while PM was characterized by pulses of marine macrophytes input and should be managed with care in respect to its catchment for water use and dam constructions as a shortage of fresh water can alter the estuarine ecology.

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23

Morgan, David L., and Riki Kobayashi. "Triple point corresponding states in long-chain n-alkanes." Fluid Phase Equilibria 63, no. 3 (1991): 317–27. http://dx.doi.org/10.1016/0378-3812(91)80038-w.

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24

Bhattacharjee, Indranil, Anupam Ghosh, Nandita Chowdhury, Soroj Kumar Chatterjee, Goutam Chandra, and Subrata Laskar. "n-Alkane Profile of Argemone mexicana Leaves." Zeitschrift für Naturforschung C 65, no. 9-10 (October 1, 2010): 533–36. http://dx.doi.org/10.1515/znc-2010-9-1001.

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An n-hexane extract of fresh, mature leaves of Argemone mexicana (Papaveraceae), containing thin-layer epicuticular waxes, has been analysed for the first time by TLC, IR and GLC using standard hydrocarbons. Seventeen long-chain alkanes (n-C18 to n-C34) were identified and quantified. Nonacosane (n-C29) was established as the n-alkane with the highest amount, whilst octadecane (n-C18) was the least abundant component of the extracted wax fraction. The carbon preference index (CPI) calculated for the hydrocarbon sample with the chain lengths between C18 and C34 was 1.2469, showing an odd to even carbon number predominance.

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25

He, Jinxian, Shengyin Zhang, Xiaoli Zhang, Yu Qian, Haijun He, and Hongchen Wu. "Composition and Distribution Characteristics and Geochemical Significance of n-Alkanes in Core Sediments in the Northern Part of the South Yellow Sea." Journal of Chemistry 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/4741939.

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The South Yellow Sea is an important carbon sink and a significant research area of carbon cycle. After studying the composition and distribution of n-alkanes in a 250 cm long sediment core in the northern part of South Yellow Sea, it can be found that all n-alkanes of sediment samples in this research are distributed in three types, that is, double peak groups, predominance of long-chain n-alkanes, and predominance of short-chain n-alkanes. The average values of∑C25−35/∑C15−21,∑C27+29+31/∑C15+17+19,∑C21-/∑C22+, and(C27+C29+C31+C33)/∑C14–38are 1.92, 4.22, 0.51, and 0.35, respectively; all above outcomes indicate significant predominance of terrigenous inputs. The average values of C31/C29 and ACL are 1.04 and 29.92, respectively; these results reflect that herbaceous plants and ligneous plants account for similar percentages in the sediment core samples. The average values of CPI1 of short-chain alkanes are 0.80, reflecting the apparent even predominance, which is the result of microbial degradation. The average values of CPI2 of long-chain alkanes of most samples are 2.77, reflecting the apparent odd predominance. The average values of CPI and Pr/Ph, as well as the Pr/nC17and Ph/nC18correlation diagram, reflect that the organic matter is immature and suggest reductive sedimentary environment.

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Whyte, Lyle G., Jalal Hawari, Edward Zhou, Luc Bourbonnière, William E. Inniss, and Charles W. Greer. "Biodegradation of Variable-Chain-Length Alkanes at Low Temperatures by a Psychrotrophic Rhodococcussp." Applied and Environmental Microbiology 64, no. 7 (July 1, 1998): 2578–84. http://dx.doi.org/10.1128/aem.64.7.2578-2584.1998.

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ABSTRACT The psychrotroph Rhodococcus sp. strain Q15 was examined for its ability to degrade individual n-alkanes and diesel fuel at low temperatures, and its alkane catabolic pathway was investigated by biochemical and genetic techniques. At 0 and 5°C, Q15 mineralized the short-chain alkanes dodecane and hexadecane to a greater extent than that observed for the long-chain alkanes octacosane and dotriacontane. Q15 utilized a broad range of aliphatics (C10 to C21 alkanes, branched alkanes, and a substituted cyclohexane) present in diesel fuel at 5°C. Mineralization of hexadecane at 5°C was significantly greater in both hydrocarbon-contaminated and pristine soil microcosms seeded with Q15 cells than in uninoculated control soil microcosms. The detection of hexadecane and dodecane metabolic intermediates (1-hexadecanol and 2-hexadecanol and 1-dodecanol and 2-dodecanone, respectively) by solid-phase microextraction–gas chromatography-mass spectrometry and the utilization of potential metabolic intermediates indicated that Q15 oxidizes alkanes by both the terminal oxidation pathway and the subterminal oxidation pathway. Genetic characterization by PCR and nucleotide sequence analysis indicated that Q15 possesses an aliphatic aldehyde dehydrogenase gene highly homologous to the Rhodococcus erythropolis thcA gene. Rhodococcus sp. strain Q15 possessed two large plasmids of approximately 90 and 115 kb (shown to mediate Cd resistance) which were not required for alkane mineralization, although the 90-kb plasmid enhanced mineralization of some alkanes and growth on diesel oil at both 5 and 25°C.

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Yamane, Kunio, Shigeru Matsuyama, Kensuke Igarashi, Motoo Utsumi, Yoshihiro Shiraiwa, and Tomohiko Kuwabara. "Anaerobic Coculture of Microalgae with Thermosipho globiformans and Methanocaldococcus jannaschii at 68°C Enhances Generation ofn-Alkane-Rich Biofuels after Pyrolysis." Applied and Environmental Microbiology 79, no. 3 (November 26, 2012): 924–30. http://dx.doi.org/10.1128/aem.01685-12.

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ABSTRACTWe tested different alga-bacterium-archaeon consortia to investigate the production of oil-like mixtures, expecting thatn-alkane-rich biofuels might be synthesized after pyrolysis.Thermosipho globiformansandMethanocaldococcus jannaschiiwere cocultured at 68°C with microalgae for 9 days under two anaerobic conditions, followed by pyrolysis at 300°C for 4 days.Arthrospira platensis(Cyanobacteria),Dunaliella tertiolecta(Chlorophyta),Emiliania huxleyi(Haptophyta), andEuglena gracilis(Euglenophyta) served as microalgal raw materials.D. tertiolecta,E. huxleyi, andE. graciliscocultured with the bacterium and archaeon inhibited their growth and CH4production.E. huxleyihad the strongest inhibitory effect. Biofuel generation was enhanced by reducing impurities containing alkanenitriles during pyrolysis. The composition and amounts ofn-alkanes produced by pyrolysis were closely related to the lipid contents and composition of the microalgae. Pyrolysis ofA. platensisandD. tertiolectacontaining mainly phospholipids and glycolipids generated short-carbon-chainn-alkanes (n-tridecane ton-nonadecane) and considerable amounts of isoprenoids.E. gracilisalso produced mainly shortn-alkanes. In contrast,E. huxleyicontaining long-chain (31 and 33 carbon atoms) alkenes and very long-chain (37 to 39 carbon atoms) alkenones, in addition to phospholipids and glycolipids, generated a high yield ofn-alkanes of various lengths (n-tridecane ton-pentatriacontane). The gas chromatography-mass spectrometry (GC-MS) profiles of thesen-alkanes were similar to those of native petroleum crude oils despite containing a considerable amount ofn-hentriacontane. The ratio of phytane ton-octadecane was also similar to that of native crude oils.

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Erickson, M. H., M. Gueneron, and B. T. Jobson. "Measuring long chain alkanes in diesel engine exhaust by thermal desorption PTR-MS." Atmospheric Measurement Techniques 7, no. 1 (January 27, 2014): 225–39. http://dx.doi.org/10.5194/amt-7-225-2014.

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Abstract. A method using thermal desorption sampling and analysis by proton transfer reaction mass spectrometry (PTR-MS) to measure long chain alkanes (C12–C18) and other larger organics associated with diesel engine exhaust emissions is described. Long chain alkanes undergo dissociative proton transfer reactions forming a series of fragment ions with formula CnH2n+1. The PTR-MS is insensitive to n-alkanes less than C8 but displays an increasing sensitivity for larger alkanes. Fragment ion distribution and sensitivity is a function of drift conditions. At 80 Td the most abundant ion fragments from C10 to C16 n-alkanes were m/z 57, 71 and 85. The mass spectrum of gasoline and diesel fuel at 80 Td displayed ion group patterns that can be related to known fuel constituents, such as alkanes, alkylbenzenes and cycloalkanes, and other compound groups that are inferred from molecular weight distributions such as dihydronapthalenes and naphthenic monoaromatics. It is shown that thermal desorption sampling of gasoline and diesel engine exhausts at 80 Td allows for discrimination against volatile organic compounds, allowing for quantification of long chain alkanes from the abundance of CnH2n+1 fragment ions. The total abundance of long chain alkanes in diesel engine exhaust was measured to be similar to the total abundance of C1–C4 alkylbenzene compounds. The abundance patterns of compounds determined by thermal desorption sampling may allow for emission profiles to be developed to better quantify the relative contributions of diesel and gasoline exhaust emissions on organic compounds concentrations in urban air.

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29

Jay‐Gerin, J. ‐P, and C. Ferradini. "On excess electron transport in liquid long chain n‐alkanes." Journal of Chemical Physics 93, no. 5 (September 1990): 3718–20. http://dx.doi.org/10.1063/1.458803.

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30

Erickson, M. H., M. Gueneron, and B. T. Jobson. "Measuring long chain alkanes in diesel engine exhaust by thermal desorption PTR-MS." Atmospheric Measurement Techniques Discussions 6, no. 4 (July 1, 2013): 6005–46. http://dx.doi.org/10.5194/amtd-6-6005-2013.

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Abstract. A method using thermal desorption sampling and analysis by PTR-MS to measure long chain alkanes (C12-C18) and other larger organics associated with diesel engine exhaust emissions is described. Long chain alkanes undergo dissociative proton transfer reactions forming a series of fragment ions with formula CnH2n+1. The PTR-MS is insensitive to n-alkanes less than C8 but displays an increasing sensitivity for larger alkanes. Fragment ion distribution and sensitivity is a function of drift conditions. At 80 Td the most abundant ion fragments from C10 to C16 n-alkanes were m/z 57, 71 and 85. The mass spectrum of gasoline and diesel fuel at 80 Td displayed ion group patterns that can be related to known fuel constituents, such as alkanes, alkylbenzenes and cycloalkanes, and other compound groups that are inferred from molecular weight distributions such as dihydronapthalenes and naphthenic monoaromatics. It is shown that thermal desorption sampling of gasoline and diesel engine exhausts at 80 Td allows for discrimination against light alkanes and alkenes which are a major constituent of both exhausts, allowing for quantification of higher molecular weight alkanes from the abundance of CnH2n+1 fragment ions. Using this approach, the molar abundance of C12-C18 alkanes in diesel engine exhaust was found to be 75% that of the total C1-C4 alkylbenzene abundance. While the PTR-MS mass spectra of gasoline and diesel exhaust looked similar, the abundance of higher molecular weight compounds relative to that of C4-alkylbenzenes was much greater in diesel engine exhaust. The abundance patterns of compounds determined by thermal desorption sampling may allow for emission profiles to be developed to better quantify the relative contributions of diesel and gasoline exhaust emissions of larger organic compounds to urban air concentrations.

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31

Nikolić, Biljana, Marina Todosijević, Iris Đorđević, Jovana Stanković, Zorica S. Mitić, Vele Tešević, and Petar D. Marin. "Nonacosan-10-ol and n-Alkanes in Needles of Pinus halepensis." Natural Product Communications 15, no. 5 (May 2020): 1934578X2092097. http://dx.doi.org/10.1177/1934578x20920970.

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In needle cuticular wax of Pinus halepensis, nonacosan-10-ol is high (77.08% on average). n-Alkanes ranged from C18 to C35 with the most dominant C27 and C29 (32.4% and 25.8%, respectively). The carbon preference index ranged from 3.2 to 5.4 (3.4 on average), while the average chain length ranged from 14.0 to 18.0 (17.2 on average). Long-chain n-alkanes strongly dominated (95.1%).

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32

Sekhar, G. Chandra, P. Venkatesu, T. Hofman, and M. V. Prabhakara Rao. "Solid–liquid equilibria of long chain n-alkanes (C18–C28) in N,N-dimethylacetamide." Fluid Phase Equilibria 201, no. 2 (September 2002): 219–31. http://dx.doi.org/10.1016/s0378-3812(02)00086-9.

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33

ALI, H. A. M., R. W. MAYES, B. L. HECTOR, A. K. VERMA, and E. R. ØRSKOV. "The possible use of n-alkanes, long-chain fatty alcohols and long-chain fatty acids as markers in studies of the botanical composition of the diet of free-ranging herbivores." Journal of Agricultural Science 143, no. 1 (February 2005): 85–95. http://dx.doi.org/10.1017/s0021859605004958.

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Few methods exist for estimating quantitatively the diet composition of free-ranging herbivores. The current study examined whether long-chain fatty alcohols (alcohols) or long-chain fatty acids (acids) could be used along with n-alkanes to allow reliable diet composition estimates to be made in herbivores consuming complex diets. Twelve Scottish Blackface wether sheep housed in metabolism crates were fed four different mixtures of three plant species (three animals per mixture) for a seven-period experiment. Concentrations of cuticular wax n-alkanes, alcohols and acids were estimated in samples of individual plant species, and the faeces from animals that consumed mixtures of these species. These concentrations were then used to calculate the dietary proportions of each species by a least-squares optimization procedure. To explore the differences between the estimation methods (individual markers and their combinations), the mean squares of errors (EMS) between the actual and predicted proportions of plant species were calculated.In three out of the four mixtures, alcohols had the lowest discrepancies (lowest EMS values), followed by n-alkanes and then acids. Acids yielded the lowest discrepancy in one mixture and the highest in the others.It is concluded that, for this particular set of mixtures, alcohols had great potential to estimate composition of complex diets. However, the estimation using acids was less good and n-alkanes were of intermediate potential. Estimation from the combination of the three marker classes was always better than using the poorest individual marker.

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34

Kundu, Somenath, and Amalendu Sinhababu. "Analysis of n-alkanes in the cuticular wax of leaves of Ficus glomerata Roxb." Journal of Applied and Natural Science 5, no. 1 (June 1, 2013): 226–29. http://dx.doi.org/10.31018/jans.v5i1.311.

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Leaf cuticle was covered by epicuticular wax consisting mainly of straight chain aliphatic hydrocarbons with a variety of substituted groups. The studies of cuticular characters of leaves had played an important role in chemotaxonomy. An n-hexane extract of fresh and mature leaves of Ficus glomerata, containing a thin layer of epicuticular waxes was analyzed for the first time by Thin Layer Chromatography, Infrared Spectroscopy, Gas Chromatography and Scanning Electron Microscopy using standard hydrocarbons. The leaves contained 18 identified long chain (C15–C33) n-alkanes except C23 accounting for 68.82% of the hydrocarbons, and an unknown number of unidentified branched chain alkanes. The predominant n-alkanes were C16 (5.92%), C17 (6.18%), C27 (5.11%), C29 (5.29%), C31 (5.47%), whilst C15 (4.21%), C18 (4.57%), C26 (3.88%), C28 (3.53%), C30 (3.43%) n-alkanes were moderately abundant. The C19 (2.53%), C20 (2.52%) and C22 (2.16%) homologues were present only in minor amounts. SEM views were also taken for epicuticular layers and hydrocarbons of the leaves. Qualitative and Quantitative characterization of n-alkanes present in the epicuticular wax can be used as an effective tool in chemotaxonomical work.

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35

Matsumoto, Genki I., Masaru Akiyama, Kunihiko Watanuki, and Tetsuya Torii. "Unusual distributions of long-chain n-alkanes and n-alkenes in Antarctic soil." Organic Geochemistry 15, no. 4 (January 1990): 403–12. http://dx.doi.org/10.1016/0146-6380(90)90167-x.

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36

MAEDA, NOBUO, and VASSILI V. YAMINSKY. "EXPERIMENTAL OBSERVATIONS OF SURFACE FREEZING." International Journal of Modern Physics B 15, no. 23 (September 20, 2001): 3055–77. http://dx.doi.org/10.1142/s0217979201007051.

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Capillary phase transitions and those induced by interfaces, like pre-melting, have been studied for decades. The related phenomenon of surface freezing has not been explored so extensively. We review experiments on surface freezing, those of long-chain n-alkanes in particular, and place the results within the wider thermodynamic framework of surface phase transitions. Surface freezing plays an important role in nucleation and crystallization of bulk long-chain n-alkanes. Implications for capillary melting and freezing of substances at nanoscales are discussed. Theoretical aspects of condensed capillary phase transitions will be reviewed separately.

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37

Xia, Gao, Su Yun-lan, Xie Bao-quan, Fu Dong-sheng, and Wang Du-jin. "Progress in Studies of Confined Crystallzaiton of Long-chain n-Alkanes." Acta Polymerica Sinica 014, no. 1 (April 15, 2014): 22–30. http://dx.doi.org/10.3724/sp.j.1105.2014.13290.

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38

Goworek, T., M. Pietrow, R. Zaleski, and B. Zgardzińska. "Positronium in high temperature phases of long-chain even n-alkanes." Chemical Physics 355, no. 2-3 (January 2009): 123–29. http://dx.doi.org/10.1016/j.chemphys.2008.11.019.

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39

Blasig, R., J. Huth, P. Franke, P. Borneleit, W. H. Schunck, and H. G. M�ller. "Degradation of long-chain n-alkanes by the yeast Candida maltosa." Applied Microbiology and Biotechnology 31-31, no. 5-6 (October 1989): 571–76. http://dx.doi.org/10.1007/bf00270797.

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40

Ghogomu, Paul Mingo, Mohammed Bouroukba, Jacques Dellacherie, Daniel Balesdent, and Michel Dirand. "On the ideality of liquid mixtures of long-chain n-alkanes." Thermochimica Acta 306, no. 1-2 (November 1997): 69–71. http://dx.doi.org/10.1016/s0040-6031(97)00301-8.

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41

Ali, H. A. M., R. W. Mayes, B. L. Hector, and E. R. Ørskov. "The possible use of n-alkanes, long-chain fatty alcohols and long-chain fatty acids as markers in studies of the botanical composition of the diet of free-ranging herbivores." Proceedings of the British Society of Animal Science 2003 (2003): 155. http://dx.doi.org/10.1017/s1752756200013144.

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Анотація:

Few methods exist for quantitatively estimating the diet composition of free-ranging herbivores. Because their patterns differ between species, plant n-alkanes have been successfully used as faecal markers to estimate the botanical composition of simple diets, however, the reliability of this methods may decline as the number of dietary plant species increases (Dove and Mayes, 1996). The objective of this study was to examine whether additional plant-wax compounds, such as long-chain fatty alcohols (Alc) or long–chain fatty acids (Ac) could be used along with n-alkanes (Alk) to allow reliable diet composition estimates to be made in herbivores consuming complex diets.

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de Silva, D. S. M., J. P. Gorce, P. A. S. R. Wickramarachchi, and S. J. Spells. "FTIR studies of molecular disorder in long chain n-alkanes: chain tilt and chain end disorder." Macromolecular Symposia 184, no. 1 (August 2002): 67–78. http://dx.doi.org/10.1002/1521-3900(200208)184:1<67::aid-masy67>3.0.co;2-z.

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43

Song, Ning, Mei Jun Li, and Jin Chuan Zhang. "Even and Odd Carbon Predominance Coexisting N-Alkanes in Paleogene Dark Shale in Jinhu Sag of Subei Basin." Applied Mechanics and Materials 312 (February 2013): 871–75. http://dx.doi.org/10.4028/www.scientific.net/amm.312.871.

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Gas chromatograms of saturated hydrocarbons of shale rock extracts show three patterns of n-alkanets in the second member of Funning formation (E1f2) in Jinhu Sag of Subei basin, eastern China. Three patterns of n-alkanets are the odd-to-even carbon predominance, the even-to-odd carbon predominance, and the even and odd carbon predominance coexisting, respectively. In this paper, the characteristics of n-alkanet coexisting even and odd carbon predominance and its origin and sedimentary environment are investigated only. The short-chain n-alkanets and long-chain n-alkanets are characterized by pronounced odd carbon predominance, with the dominant carbon of nC15, nC17 and of nC25, nC27, nC29 and nC31. The mid-chain n-alkanets are dominated by even carbon predominance, with the dominant carbon of nC20 and nC22. The composition of biomarkers are characterized by phytane preference, high gamma cerate abundance, the presence of β-carotene and C24-tetracyclic terrapin, which indicate that the organic matter in source rocks deposited in an anoxic, hyper saline lacus trine environment. The biomarkers are no homogeneous, which shows that salinity and redo is not constant in pale-lacus trine. The n-alkanets are mainly derived from algae in the ancient lake and macro pyres on land or around the edges of the ancient lake. The n-alkanets distribution patterns of the dark shales studied are believed not to be dependent on the redo in the depositional environments or the salinity of the water body, but to be associated with original organic matter composition.

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Skreczko, Sylwia, Artur Szymczyk, and Weronika Nadłonek. "Impacts of vegetation and palaeohydrological changes on the n-alkane composition of a Holocene peat sequence from the Upper Vistula Valley (southern Poland)." Journal of Soils and Sediments 21, no. 7 (May 27, 2021): 2709–18. http://dx.doi.org/10.1007/s11368-021-02981-4.

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Abstract Purpose The analysis of n-alkanes in palaeoenvironmental studies of peatlands is mainly limited to ombrogenous peatlands which are a rare feature in the environment. Using n-alkane and plant macrofossil analysis, we have tracked changes in the environment in the valley of a large Central European river. We tested the possibilities for applying such studies to low-moor bogs which are the most commonly occurring type of bog in the world. Materials and methods Representative peat samples were taken from two profiles in a peatland located in the Vistula Valley (southern Poland), and they were analysed for the occurrence and distribution of biomarkers. The distribution of n-alkanes was determined using gas chromatography-mass spectrometry (GC–MS). The botanical composition of the samples was determined by analysis of plant macrofossil remains, and the degree of peat decomposition was also determined. Results and discussion Samples of low-moor peat were characterised by a prevalence of medium- and long-chain n-alkane homologues, which is typical for higher plants. The variable values of the CPI, CPI (25–31), and the C23/C25 ratio have provided information on the stages of formation of the Zapadź bog. The source of n-alkane differentiation is vegetation change related to palaeohydrological dynamics and palaeoenvironmental conditions within the peatland. Conclusions We have shown that analysis of n-alkanes can be successfully used in low-moor bogs as a complement to palaeobotanical and palaeozoological methods. The bringing together of these types of research enables changes in the ecosystems of large river valleys to be tracked.

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Santos, Lourdes Campaner dos, Anne L. Dokkedal, Miriam Sannomiya, Maria Carla Piza Soares, and Wagner Vilegas. "n-alkanes from Paepalanthus Mart. species (Eriocaulaceae)." Acta Botanica Brasilica 19, no. 4 (December 2005): 727–32. http://dx.doi.org/10.1590/s0102-33062005000400007.

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This work presents the study of nonpolar compounds from plants belonging to the genus Paepalanthus Mart. (Eriocaulaceae). Long-chain linear aliphatic hydrocarbons were identified by GC-FID and GC-MS. The results indicate that Paepalanthus subg. Platycaulon species present a very homogenous profile, with carbon chains of n-alkanes ranging from C25 to C31, most samples presenting higher frequencies of C27 and C29 homologues. Paepalanthus subg. Paepalocephalus species may be distinguished from one another by the distribution of main n-alkanes. P. macrocephalus, subsect. Aphorocaulon species, presents alkanes with odd-carbon numbers and P. denudatus and P. polyanthus, Actinocephalus species, present alkanes with quite distinctive profiles, with many shorter chains and a high frequency of even-carbon number, especially P. polyanthus. The results obtained indicate that the distribution of alkanes can be a useful taxonomic character, as do polar compounds like flavonoid glycosides.

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Verstraete, Lander, Tamara Rinkovec, Hai Cao, Hywel I. Reeves, Jeremy N. Harvey, and Steven De Feyter. "Chiral Adsorption Conformations of Long-Chain n-Alkanes Induced by Lattice Mismatch." Journal of Physical Chemistry C 125, no. 2 (January 7, 2021): 1557–63. http://dx.doi.org/10.1021/acs.jpcc.0c09825.

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Gorce, Jean-Philippe, and Stephen J. Spells. "FTIR studies of conformational disorder: crystal perfecting in long chain n-alkanes." Polymer 45, no. 10 (May 2004): 3297–303. http://dx.doi.org/10.1016/j.polymer.2004.03.034.

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McCabe, Clare, and George Jackson. "SAFT-VR modelling of the phase equilibrium of long-chain n-alkanes." Physical Chemistry Chemical Physics 1, no. 9 (1999): 2057–64. http://dx.doi.org/10.1039/a808085b.

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Corsetti, Stella, Thomas Rabl, David McGloin, and Johannes Kiefer. "Intermediate phases during solid to liquid transitions in long-chain n-alkanes." Physical Chemistry Chemical Physics 19, no. 21 (2017): 13941–50. http://dx.doi.org/10.1039/c7cp01468f.

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Temperature-dependent Raman spectra of tetradecane, pentadecane and hexadecane are collected and analysed to unveil the difference in the speed of their phase transitions while gaining information about their structural changes.

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Costas, Miguel. "A Lattice Model Approach to Orientational Order in Long Chain n-Alkanes." Berichte der Bunsengesellschaft für physikalische Chemie 89, no. 8 (August 1985): 850–59. http://dx.doi.org/10.1002/bbpc.19850890810.

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