Abstract  HEEP COPYRIGHT: BIOL ABS. RRM COSMETIC MATERIALS SAFETY EVALUATION PROPYLENE GLYCOL GLYCERIN 1 3 BUTYLENE GLYCOL PRISTANE LIQUID PARAFFIN SQUALANE

Abstract  This study has utilized the tools of lipid biomarker chemistry and molecular phylogenetic analyses to assess the archaeal contribution to diversity and abundance within a microbial mat and underlying sediment from a hypersaline lagoon in Baja California. Based on abundance of ether-linked isoprenoids, archaea made up from 1 to 4% of the cell numbers throughout the upper 100 mm of mat and sediment core. Below this depth archaeal lipid was two times more abundant than bacterial. Archaeol was the primary archaeal lipid in all layers. Relatively small amounts of caldarchaeol (dibiphytanyl glyceroltetraether) were present at most depths with phytanyl to biphytanyl molar ratios lowest (approximately 10 : 1) in the 4-17 mm and 100-130 mm horizons, and highest (132 : 1) in the surface 0-2 mm. Lipids with cyclic biphytanyl cores were only detected below 100 mm. A novel polar lipid containing a C(30) isoprenoid (squalane) moiety was isolated from the upper anoxic portion of the core and partially characterized. Hydrocarbon biomarker lipids included pentamethylicosane (2-10 mm) and crocetane (primarily below 10 mm). Archaeal molecular diversity varied somewhat with depth. With the exception of samples at 0-2 mm and 35-65 mm, Thermoplasmatales of marine benthic group D dominated clone libraries. A significant number of phylotypes representing the Crenarchaeota from marine benthic group B were generally present below 17 mm and dominated the 35-65 mm sample. Halobacteriaceae family made up 80% of the clone library of the surface 2 mm, and consisted primarily of sequences affiliated with the haloalkaliphilic Natronomonas pharaonis.

Abstract  In order to examine the effect of squalane to excrete PCB from the intoxicated animals, histopathological studies of Meibomian gland abnormalities were carried out in experimental PenCB (3,4,5,3',4'-pentachlorobiphenyl) intoxicated beagles treated with squalane. All experimental animals except a control group showed characteristic changes of Meibomian glands: dilation of the duct and squamous metaplasia of the alveolar cells. According to the degree of these findings, five stages were divided in the processes of Medibomian gland changes. The PenCB intoxicated dogs initially showed mild pathological changes of the glands and later moderate to severe degrees of findings. In the PenCB intoxicated animals treated with squalane, severe degree of Meibomian gland findings were found in the early stage and mild to moderate abnormalities in the late stage. The concentration of PenCB in blood varied in each animal, and the animals with advanced Medibomian gland abnormalities tended to have high level of PenCB concentration in blood. In conclusion, the effect of squalane to excrete PCB from the intoxicated animals were not determined in this study.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM MULLUS-BARBATUS TRACHURUS-TRACHURUS MERLUCCIUS-MERLUCCIUS ENGRAULIS-ENCRASICHOLUS MICROMESISTIUS-POUTASSOU COASTAL POLLUTION BIOINDICATOR POLYCHLORINATED BIPHENYL ORGANOCHLORIDE ALKYLBENZENE FOOD WEB TRANSFER BIOGENIC HYDROCARBON AGE DIFFERENCES MUSCLE LIVER GONAD

Abstract  The comedogenicity of UVA-irradiated and non-irradiated substances (squalene, oleic acid, tetradecane, isopropyl myristate, squalane and liquid paraffin) was evaluated by surface microscopy and histological examination after treating the ventral skin of rabbit ears with these substances. The lipid peroxide levels of these substances were also measured. Squalene itself was scarcely comedogenic but squalene peroxides were highly comedogenic. Both oleic acid and its peroxides were able to induce fairly large comedones and there was a good correlation between the lipid peroxide levels and the size of the comedones. The specimens biopsied from these comedones showed marked hyperplasia and hyperkeratosis of the epithelium in the follicular infundibulum and marked proliferation of the sebaceous glands. Although free fatty acids might play a role in the pathogenesis of acne, it is proposed that squalene and free fatty acids in sebum may be less comedogenic than their peroxides.

Abstract  In laboratory studies of organic aerosol particles reacting with gas-phase oxidants, high concentrations of radicals are often used to study on the timescale of seconds reactions which may be occurring over days or weeks in the troposphere. Implicit in this approach is the assumption that radical concentration and time are interchangeable parameters, though this has not been established. Here, the kinetics of OH-and Cl-initiated oxidation reactions of model single-component liquid (squalane) and supercooled (brassidic acid and 2-octyldodecanoic acid) organic aerosols are studied by varying separately the radical concentration and the reaction time. Two separate flow tubes with residence times of 2 and 66 s are used, and [OH] and [Cl] are varied by adjusting either the laser photolysis fluence or the radical precursor concentration ([O(3)] or [Cl(2)], respectively) used to generate the radicals. It is found that the rates measured by varying the radical concentration and the reaction time are equal only if the precursor concentrations are the same in the two approaches. Further, the rates depend on the concentrations of the precursor species with a Langmuir-type functional form suggesting that O(3) and Cl(2) saturate the surface of the liquid particles. It is believed that the presence of O(3) inhibits the rate of OH reaction, perhaps by reacting with OH radicals or by O(3) or intermediate species blocking surface sites, while Cl(2) enhances the rate of Cl reaction by participating in a radical chain mechanism. These results have important implications for laboratory experiments in which high concentrations of gas-phase oxidants are used to study atmospheric reactions over short timescales and may explain the variability in recent measurements of the reactive uptake of OH on squalane particles in reactor systems used in this and other laboratories.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The well-characterized Alberta Sweet Mixed Blend oil and several other oils which are commonly transported in Canada were physically weathered and then incubated with a defined microbial inoculum. The purpose was to produce quantitative data on oil components and component groups which are more susceptible or resistant to biodegradation, and to determine how oils rank in relation to each other in terms of biodegradation potential. The biodegraded oils were characterized by quantitative determination of changes in important hydrocarbon groups including the total petroleum hydrocarbons, total saturates and aromatics, and also by quantitation of more than 100 individual target aliphatic, aromatic and biomarker components. The study reveals a pattern of distinct oil composition changes due to biodegradation. which is significantly different from the pattern due to physical or short-term weathering. It is important to be able to distinguish between these two forms of loss, s

Abstract  A study of the extracts of samples recording a transgressivearegressive succession of the Werra cyclothem, Zechstein (Upper Permian), from the southern margin of the European Permian Basin (the Fore-Sudetic Monocline, Poland) provides an insight into major sources of organic matter and diagenetic processes. The studied cross-section comprises all lithologies representative for the European basin, including transgressive sandstones (Weissliegend) and organic-rich shales (Kupferschiefer) followed by carbonates as well as regressive anhydrites with intercalations of rock salt. Due to the variable influence of overlapping diagenetic processes that affected the organic matter, i.e. maturation and late diagenetic oxidation related to base metal mineralisation, a reliable comparison of the biomarker results is only possible for the major upper part of the section (ca. 38 m, including carbonates and evaporites) but not for the oxidised first 2a3 m from the base of the Kupferschiefer. The transition from carbonate to evaporate sedimentation is associated with a shift to predominant even C-numbered n-alkanes, increased abundance of carotanes and high homohopane index reflecting enhanced reducing conditions. The presence of the C25 regular isoprenoid, squalane, biphytane and the rapid decrease in the pristane/phytane ratio in the evaporites are mainly controlled by the important contribution from both halophilic and methanogenic archaea. The occurrence of gammacerane in the anhydrites suggests development of water column stratification at some stages of the sea regression. This is associated with appearance of specific aryl isoprenoids with a lycopane carbon skeleton most likely related to Botrycoccus braunii race L algae. Lycopane derivative occurrence suggests that such an algal race could have occurred since Permian (currently known Recent-Eocene). The presence of the abundant freshwater/brackish algal biomarkers in evaporititic deposits can be envisaged in the costal part of the Zechstein basin with temporary salt wedge estuary water stratification. The algae bloomed in the top fertile fresh/brackish water layer fed by rivers, and the algal biomass was deposited on the sea floor covered with evaporitic brine. The stratification periodically broke down during precipitation of the rock salt, presumably due to a decrease in riverine water input, as revealed by characteristic disappearance of gammacerane and hopane distributions similar to those observed for the carbonate rocks. The methylphenanthrenes/phenanthrene ratio was used together with methyldibenzothiophenes/ dibenzothiophene ratio to assess maturity. These maturity estimations indicate that the peak of oil window has been reached, which is confirmed by other biomarker maturity parameters based on sterane and hopane distributions. The maturity stage of oil generation and expulsion was further confirmed by the presence of solid bitumen as cements in the sandstone underlying Kupferschiefer and bitumen veins and lenses in the carbonates.

Abstract  We investigated the stimulating effect of rice bran fiber (RBF) on the fecal excretion of polychlorinated biphenyls (PCBs) in rats. Increases both in the amount of feces and in the amounts of fecally excreted PCBs were observed in proportion to the amounts of RBF added to the diet. In groups fed a diet of 10% RBF or 5% RBF, total PCBs excreted in the feces were 3.4 and 1.6 times that of the group fed a control diet for 3 weeks, respectively. Excretion rates and amounts in the group fed a 1% RBF diet were not affected in comparison with those of the group fed the control diet. RBF is found to suppress the absorption of the PCBs excreted into the rat intestinal tract, and is found to stimulate the fecal excretion of PCBs.

Abstract  The heterogeneous reaction of OH radicals with sub-micron squalane particles, in the presence of O-2, is used as a model system to explore the fundamental chemical mechanisms that control the oxidative aging of organic aerosols in the atmosphere. Detailed kinetic measurements combined with elemental mass spectrometric analysis reveal that the reaction proceeds sequentially by adding an average of one oxygenated functional group per reactive loss of squalane. The reactive uptake coefficient of OH with squalane particles is determined to be 0.3 +/- 0.07 at an average OH concentration of similar to 1 x 10(10) molecules cm(-3). Based on a comparison between the measured particle mass and model predictions it appears that significant volatilization of a reduced organic particle would be extremely slow in the real atmosphere. However, as the aerosols become more oxygenated, volatilization becomes a significant loss channel for organic material in the particle-phase. Together these results provide a chemical framework in which to understand how heterogeneous chemistry transforms the physiochemical properties of particle-phase organic matter in the troposphere.

Abstract  Laboratory studies have found that heterogeneous oxidation can affect the composition and loading of atmospheric organic aerosol particles over time scales of several days, but most studies have examined pure organic particles only. In this study, in order to probe the reactivity of organic species confined near the particle surface, the rates and products of the OH-initiated oxidation of pure squalane particles are compared to oxidation of thin coatings of squalane on ammonium sulfate particles. The squalane reaction rate constant shows a linear dependence on the organic surface area-to-volume ratio, with rate constants for coated particles up to 10 times larger than for pure particles. Changes in the carbon oxidation state and fraction of particulate carbon remaining show similar enhancements, implying that heterogeneous oxidation may exhibit a stronger effect on the loadings and properties of organic aerosol than previously estimated from laboratory studies.

Abstract  Rationale Cold EI is defined as electron ionization of cold molecules in supersonic molecular beams (SMB). Gas chromatography/mass spectrometry (GC/MS) with Cold EI provides informative mass spectra, which combine the usual library-searchable EI fragment ions with enhanced molecular ions for improved library-based identification probabilities. However, in some cases, such as in the analysis of complex petrochemical matrices, a soft ionization method that provides only molecular ions is desirable. Methods GC/MS with Cold EI was used with a fly-through ion source at selected electron energies, including at low electron energies, in an attempt to observe molecular ions alone. Results We explored low electron energy Cold EI and found that once the sample compound is cooled by the supersonic expansion it can be reheated via reflected scattered helium atoms near the skimmer. Furthermore, once a labile molecular ion is formed it can undergo undesirable collision-induced dissociation (CID) in the same way as in tandem mass spectrometry (MS/MS), and the magnitude of such CID can be significant for labile molecular ions such as those of hydrocarbons. In order to reduce these adverse effects we reduced the helium pressure at the ion source and MS vacuum chamber by increasing the nozzle-skimmer distance. Cold EI at low electron energies was explored with a squalane isomer (C sub(30)H sub(62)) and with n-C sub(24)H sub(50). Conclusions It was found that an increased nozzle-skimmer distance resulted in a noticeable increase in the abundance ratio of molecular ions to low mass fragment ions. Consequently, Cold EI at low electron energies and a large nozzle-skimmer distance converts EI into Soft Cold EI while further approaching the ideal of a molecular ion only ionization method.

Abstract  BACKGROUND: Low molecular weight haptens (<1000 Da) cannot be recognized by the immune system unless conjugated to larger carrier molecules. Antibodies to these exceptionally small antigens can still be generated with exquisite sensitivity. A detailed understanding at the molecular level of this incredible ability of antibodies to recognize haptens, is still limited compared to other antigen classes.

METHODS: Different hapten targets with a broad range of structural flexibility and polarity were conjugated to carrier proteins, and utilized in sheep immunization. Three antibody libraries were constructed and used as potential pools to isolate specific antibodies to each target. The isolated antibodies were analysed in term of CDR length, canonical structure, and binding site shape and electrostatic potential.

RESULTS: The simple, chemically naïve structure of squalane (SQA) was recognized with micromolar sensitivity. An increase in structural rigidity of the hydrophobic and cyclic coprostane (COP) did not improve this binding sensitivity beyond the micromolar range, whilst the polar etioporphyrin (POR) was detected with nanomolar sensitivity. Homoserine lactone (HSL) molecules, which combine molecular flexibility and polarity, generated super-sensitive (picomolar) interactions. To better understand this range of antibody-hapten interactions, analyses were extended to examine the binding loop canonical structures and CDR lengths of a series of anti-hapten clones. Analyses of the pre and post- selection (panning of the phage displayed libraries) sequences revealed more conserved sites (123) within the post-selection sequences, when compared to their pre-selection counterparts (28). The strong selection pressure, generated by panning against these haptens resulted in the isolation of antibodies with significant sequence conservation in the FW regions, and suitable binding site cavities, representing only a relatively small subset of the available full repertoire sequence and structural diversity. As part of this process, the important influence of CDR H2 on antigen binding was observed through its direct interaction with individual antigens and indirect impact on the orientation and the pocket shape, when combined with CDRs H3 and L3. The binding pockets also displayed electrostatic surfaces that were complementary to the hydrophobic nature of COP, SQA, and POR, and the negatively charged HSL.

CONCLUSIONS: The best binding antibodies have shown improved capacity to recognize these haptens by establishing complementary binding pockets in terms of size, shape, and electrostatic potential.

Abstract  Here we describe a method of hydrocarbon (alkanes, alkenes, dienes) identification and quantitative determination of linear saturated hydrocarbons (n-alkanes) in beeswax using gas chromatography with a mass detector technique (GC-MS). Beeswax hydrocarbons were isolated using a solid-phase extraction (SPE) technique with neutral aluminum oxide (Alumina - N, 1000 mg, 6 mL), then were separated on a non-polar gas chromatography column ZB-5HT INFERNO (20 mx0.18 mmx0.18 mu m). Qquantitative analysis of n-alkanes was conducted by the method of internal standard with squalane used as the internal standard. The basic parameters of validation (linearity and working range, limit of determination, repeatability and reproducibility, recovery) were determined. For all of the identified compounds, satisfactory (>= 0.997) coefficients of correlation in the working ranges of the method (from 0.005 to 5.0 g/100 g) were obtained. The elaborated method was characterized by satisfactory repeatability and within-laboratory reproducibility. The average coefficients of variation for the total n-alkanes did not exceed 2% under conditions of repeatability or 4% under conditions of reproducibility. The recovery for individual n-alkanes was above 94%; for their total content, it was 100.5%. In beeswax originating from Apis mellifera, n-alkanes containing from 20 to 35 carbon atoms in their molecules were determined. The total content of these alkanes was between 9.08 g and 10.86 g/100 g (on average, 9.81 g/100 g). Additionally, apart from the saturated hydrocarbons, unsaturated hydrocarbons and dienes were identified.

Abstract  Immunogenicity of inactivated tissue-culture-derived duck enteritis virus (DEV) vaccines was evaluated in white Pekin and mallard ducks. DEV from a Lake Andes outbreak was propagated in chicken embryo fibroblast cells, inactivated with beta-propiolactone, and emulsified with Freund's adjuvant (FA), multiple-oil emulsion (MOE), or Squalane-pluronic L121 (L121). White Pekin and mallard ducklings were vaccinated at 2 or 3 wk of age, respectively. Challenge at 2 wk postvaccination with a virulent DEV isolated from a Long Island outbreak indicated that inactivated Lake Andes (ILA) vaccine mixed with any of the above adjuvants conferred protection, even with a single-dose inoculation Antibody responses to vaccination, as determined by indirect enzyme-linked immunosorbent assay, showed that ILA virus with FA induced an early production of antibodies similar to that induced by commercially available modified live virus (MLV) vaccine. However, the mean anti-duck virus enteritis (DVE) IgG titers determined by multiple samplings during the first 35 days postvaccination showed titers from ILA virus with FA to beat least 10 times higher than those induced by MLV vaccine. The highest antibody titers were induced by ILA mixed with FA followed by ILA mixed with the MOE and L121. The results of this study indicated that inactivated vaccine is as efficacious as modified live vaccine in enhancing protection against virulent DEV in waterfowl.

Abstract  Computerized gas chromatography-mass spectrometry of biomarkers in crude oils of East Siberia (eastern Siberian Platform, Nepa-Botuobiya dome) permitted revealing different types of primary organic matter on the basis of biochemistry and deposition environment, which correspond to a number of successive oil and gas sources.

All commercial Upper Proterozoic and Lower Cambrian oils of the study region are rich in 12-13-monomethylalkanes, tricyclic heilanthanes, and homohopane C-35 as compared with lower homolog C-34. This oil family, apparently, originates From plankton- or bacteria-derived organic matter buried in anoxic basins favorable for preservation of homohopane, among Riphean and Vendian carbonate, carbonate-argillaceous (as evidenced by scarce or absent diasteranes), and carbonaceous silts on the passive margin of the Siberian craton.

The Upper Permian and Mesozoic oils of the Vilyui basin show fairly high contents of diasteranes and rearranged hopanes (17 alpha(H)-diahopane and 18 alpha(H)-norneohopane), possibly originated from bacterial precursors which were oxidized and rearranged by acidic clay catalysis. The presence of diasteranes and diahopane attests to terrigenous (and possibly, coaliferous) source rock deposited, mast likely, in Permian fluvial, lacustrine, and marshy environments.

Considerable amounts of gammacerane, squalane, and pregnane in the Permian oils of the Yuzhno-Tigyanskoe deposit (Anabar-Khatanga saddle) are indicative of hypersaline environment of source-rock deposition. The oil may have been genetically related to Devonian salt-bearing deposition of the Lena-Anabar basin.

Abstract  The Kremna Basin is located in south west Serbia, in the Zlatibor area, which is part of the Internal Dinarides. This basin is note worthy because of the type of bedrock drainage, which it represents. It was formed on ultrabasic rocks and volcanic materials that influenced the occurrence of organic matter (OM) in the basin fill. The objective of the study was to determine the organic geochemical characteristics of sediments from the central part of the Kremna Basin.

The sediments studied belong to an intrabasinal facies, in which two sequences were distinguished. The lower sequence occurs at depths of 216-343 m, while the upper sequence is found from 13.5-216 m.

At the start of basin development (265-343 m) sedimentation took place in shallow alkaline water, rich in Mg ions. Through time, a slight deepening of the basin occurred. This was followed by chemical deposition of carbonates (216-265 m). The most important change in the sedimentary environment occurred with the formation of sediments marking the transition between the sequences (at about 200 m).

Sediments from the lower sequence are characterized by the dominance of dolomite and magnesite. There are indications of volcanic activity, i.e. tuff layers and the presence of searlesite. The upper sequence is characterized by the prevalence of calcite and dolomite. The amounts of MgO, Na2O and B are higher in the lower sequence, whereas the CaO content is higher in the upper sequence.

The sediments contain different amounts of immature OM (late diagenesis). Biomarker analysis shows diverse precursors of the sedimentary OM: methanogenic archaea, photosynthetic green sulfur bacteria (Chlorobiaceae), bacterivorous ciliates, various bacteria, both photosynthetic and non-photosynthetic, the green unicellular microalga, Botryococcus braunii race A (exclusively in the upper sequence) and terrestrial plants. The lower sequence contains lower amount OM, composed primarily of kerogen II/III and III types, indicating a higher contribution of the allochtonous biomass of land plants from the lake catchment, particularly in the lower part. The sediments of the upper sequence are enriched in autochthonous aquatic OM, which comprises mostly kerogen I, I/II and II types. The transition from the lower sequence to the upper one is associated with a decrease in pristane to phytane ratio, gammacerane index and content of C-28 steroids, absence or significantly lower amount of squalane, absence of C-24 and C-25 regular isoprenoids, 8-methyl-2-methyl-2-(4,8,12-trimethyltridecyl) chroman and C-30 hop-17(21)-ene.

Pyrolytic experiments showed that the sediments of the upper sequence, rich in aquatic OM, at a catagenetic stage could be a source of liquid hydrocarbons. The values of hopane, sterane and phenanthrene maturation parameters indicate that through pyrolysis at 400 degrees C the samples investigated reached a value of vitrinite reflectance equivalent of approximately 0.70%. It was estimated that the sediments should be found at depths of 2300-2900 m in order to become active source rocks. The calculated minimum temperature, necessary for catagenetic hydrocarbon generation, is between 103 and 107 degrees C.

Abstract  Free and sulfur-bound biomarkers in sediments deposited in the northern proto North Atlantic (Newfoundland Basin, ODP Site 1276) during the Cenomanian-Turonian oceanic anoxic event 2 (OAE-2) were studied. The delta C-13 records of phytane and lycopane confirmed the stratigraphic position of the positive carbon isotope excursion associated with OAE-2, previously reported for total organic carbon (TOC) and beta,beta-homohopane. Sediments before and after the OAE-2 interval were poor in organic matter (OM) and comprised numerous gravity flow deposits. The interval itself was composed of pelagic sediments with occasionally a much higher TOC content of up to 12.7%. The OAE-2 sediments were characterized by a low amount of terrestrial OM since the dominant biological sources of the biomarkers were aquatic in origin. High hopane, pentamethylicosane (PMI), and squalane abundances in the OM-rich sediments pointed to a relatively high input of prokaryotes, partly derived from cyanobacteria, as suggested by the occasional occurrence of 2-methylhopanes. PMI comprised both the regular and irregular isomer and changes in the delta C-13 of PMI are thought to reflect contributions from methanogenic and methanotrophic archea. The high relative concentration of lycopane indicated that bottom water conditions were anoxic during large parts of the OAE-2 interval. In one horizon, trace amounts of isorenieratane provided evidence for the occasional occurrence of photic zone anoxia. Taken together, the data imply that oceanic anoxia, and probably also high productivity, reached the northernmost part of the proto-North Atlantic during OAE-2, albeit that photic zone anoxia was much less common than in the southern proto-North Atlantic. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  Percutaneous absorption of ethyl-alcohol (64175), perhydrosqualene (111013), and p-cymene (99876) was investigated. Male albino-mice were treated topically with 0.1 milliliter of radio labeled solutions of one of the test agents. In some tests with ethyl-alcohol and perhydrosqualene, the stratum corneum was removed before treatment. At selected times, the skin was removed and analyzed for radioactivity. Absorption rates were 10.5 and 0.12 nanomoles per square centimeter per minute for ethyl-alcohol and perhydrosqualene, respectively, for nonabraded skin. When the stratum corneum was removed, ethyl-alcohol penetration rate increased to 200 nanomoles per square centimeter per minute, but the rate for perhydrosqualene did not change. The penetration rate of p-cymene was 32 nanomoles per square centimeter per minute over 1 hour. The authors conclude that dermal absorption is affected by the epidermal barrier and the removal capacity of the blood. The liposolubility of the agent also affects its penetration through the epidermal stratum.

Abstract  Squalene and its hydrogenated derivate squalane are widely used in the pharmaceutical and cosmetic fields. The two compounds are mainly produced from the liver oil of deep sea sharks and from olive oil distillates. Squalene and squalane from shark cost less than the same compounds derived from olive oil, and the use of these shark-derived compounds is unethical in cosmetic formulations. In this work we investigate whether 13C/12C and 2H/1H ratios can distinguish olive oil from shark squalene/squalane and can detect the presence of shark derivates in olive oil based products. The 13C/12C ratios (expressed as delta 13C values) of bulk samples and of pure compounds measured using isotope ratio mass spectrometry (IRMS) were significantly lower in authentic olive oil squalene/squalane (N: 13; -28.4 +/- 0.5ppt; -28.3 +/- 0.8ppt) than in shark squalene/squalane samples (N: 15; -20.5 +/- 0.7ppt; -20.4 +/- 0.6ppt). By defining delta 13C threshold values of -27.4ppt and -26.6ppt for olive oil bulk and pure squalene/squalane, respectively, illegal addition of shark products can be identified starting from a minimum of 10%. 2H/1H analysis is not useful for distinguishing the two different origins. delta 13C analysis is proposed as a suitable tool for detecting the authenticity of commercial olive oil squalene and squalane samples, using IRMS interfaced to an elemental analyser if the purity is higher than 80% and IRMS interfaced to a gas chromatography/combustion system for samples with lower purity, including solutions of squalane extracted from cosmetic products.

Abstract  Absorption, distribution, and release of squalane were studied in rainbow trout fed a diet containing 0.05% of this alkane. Estimated squalane absorption was about 40% of the dose. After three months of exposure, the residues in the whole body reached a steady equilibrium value of about 16- 18 micrograms/g. The most pronounced deposition occurred in the liver (1671 micrograms/g after 10 months), while the concentration of squalane in the adipose tissue was below 2 micrograms/g. During the depuration period, half of the contaminated trout were fed a squalane-free diet, while the others were starved. After two months, the body burden amounted to 65% and 80% of the alkane previously accumulated in starved and fed trout, respectively. In the starved group, 43% of the squalane initially stored in the liver was lost, whereas the loss in the fed fish liver was 52%. These results were compared with existing data on other alkanes. (Author 's abstract)