Naturally Occurring Allotropes of Carbon.

Carbon is one of the most important chemical elements, forming a wide range of important allotropes, ranging from diamond over graphite to nanostructural materials such as graphene, fullerenes, and carbon nanotubes (CNTs). Especially these nanomaterials play an important role in technology and are commonly formed in laborious synthetic processes that often are of high energy demand. Recently, fullerenes and their building blocks (buckybowls) have been found in natural fossil materials formed under geological conditions. The question arises of how diverse nature can be in forming different types of natural allotropes of carbon. This is investigated here, using modern analytical methods such as ultrahigh-resolution mass spectrometry and transmission electron microscopy, which facilitate a detailed understanding of the diversity of natural carbon allotropes. Large fullerenes, fullertubes, graphene sheets, and double- and multiwalled CNTs together with single-walled CNTs were detected in natural heavy fossil materials while theoretical calculations on the B3LYP/6-31G(d) level of theory using the ORCA software package support the findings.

Chemoselective umpolung of thiols to episulfoniums for cysteine bioconjugation.

Cysteine conjugation is an important tool in protein research and relies on fast, mild and chemoselective reactions. Cysteinyl thiols can either be modified with prefunctionalized electrophiles, or converted into electrophiles themselves for functionalization with selected nucleophiles in an independent step. Here we report a bioconjugation strategy that uses a vinyl thianthrenium salt to transform cysteine into a highly reactive electrophilic episulfonium intermediate in situ, to enable conjugation with a diverse set of bioorthogonal nucleophiles in a single step. The reactivity profile can connect several nucleophiles to biomolecules through a short and stable ethylene linker, ideal for introduction of infrared labels, post-translational modifications or NMR probes. In the absence of reactive exogenous nucleophiles, nucleophilic amino acids can react with the episulfonium intermediate for native peptide stapling and protein-protein ligation. Ready synthetic access to isotopologues of vinyl thianthrenium salts enables applications in quantitative proteomics. Such diverse applications demonstrate the utility of vinyl-thianthrenium-based bioconjugation as a fast, selective and broadly applicable tool for chemical biology.

Comparison of Subcutaneous versus Intramuscular Dexmedetomidine-Midazolam-Ketamine-Morphine (DMKM) Mixture as Chemical Restraint for Endoscopic Sex Determination in Aldabra Giant Tortoises (Aldabrachelys gigantea).

Sex identification through coelioscopy is a minimally invasive surgical technique used to determine the sex of chelonians by directly visualizing their internal reproductive organs. An adequate anaesthesiologic plan is essential to guarantee patient immobilization and proper analgesia during the entire surgical procedure. In this study, we evaluated the effects of a combination of dexmedetomidine (0.05 mg/kg), midazolam (1 mg/kg), ketamine (8 mg/kg), and morphine (1 mg/kg) (DMKM) randomly delivered intramuscularly (IM) or subcutaneously (SC) in twenty-one Aldabra giant tortoise (Aldabrachelys gigantea) into the right antebrachium for celioscopic sex identification. Heart rate (HR), respiratory rate (RR), and body temperature (BT) were measured, along with the skeletal muscle tone of the thoracic and pelvic limbs, neck retraction reflex, palpebral reflex, and jaw tone every 15 min. The anaesthesiologic plan was considered to be adequate at the loss of the thoracic and pelvic limb retraction reflexes. After a 45 min interval, if the anaesthetic plan was deemed insufficient for the celioscopic procedure, a 5 mg/kg dose of propofol was administered intravenously into the subcarapacial venous plexus. At the end of the procedure, atipamezole (0.5 mg/kg) and flumazenil (0.05 mg/kg) were administered intramuscularly into the left antebrachium as reversal agents. Both HR and RR decreased from baseline to both 15 and 30 min. Due to the persistence of thoracic and pelvic limb retraction reflexes 45 min after DMKM administration, 6/11 (55%) cases in the SC group required the additional administration of propofol, in contrast to only 1/10 (10%) cases in the IM group (p = 0.05). The recovery times were comparable between the successfully induced animals in the IM and SC groups. In this study, the intramuscular administration of a DMKM combination quickly produced chemical restraint, suitable for celioscopic sex determination.

Sex identification in juvenile and adult Indonesian blue-tongued skinks (Tiliqua gigas) through cystoscopy and accuracy of contrast radiography.

OBJECTIVE: To describe a nonsurgical endoscopic technique for sex identification in Indonesian blue-tongued skinks (Tiliqua gigas) and to assess accuracy of contrast radiography of the hemipenile/hemiclitoral pouches. ANIMALS: 42 clinically healthy Indonesian blue-tongued skinks between 6 months and 3 years old and weighing between 22 and 550 g. METHODS: Cystoscopy was performed under general anesthesia. Gonads were visualized through the transparency of the urinary bladder, and their gross morphology was described. Contrast was applied in the tail pouches before obtaining full-body radiographs. Two radiologists, blinded to the sex of the skink, evaluated the radiographs. RESULTS: Cystoscopy was achieved in all 42 skinks. Visualization of the gonads through the urinary bladder was possible in 41 (98%; 95% CI, 87% to 99%) of the skinks, with 18 of them identified as males and 23 identified as females. Median procedure time was 60 seconds (range, 25 to 180 seconds) and was not associated with procedure order (-0.69; 95% CI, -1.83 to 0.45) or with the weight (0.02 g; 95% CI, -0.07 to 1.0) or the identified sex (11.7; 95% CI, -15.07 to 38.45) of the skink. Radiographs had a sensitivity of 69.6% (95% CI, 47.1% to 86.8%) and a specificity of 75.0% (47.6% to 92.7%) to identify female skinks. All the skinks recovered uneventfully. CLINICAL RELEVANCE: Cystoscopic sex identification is feasible in Indonesian blue-tongued skinks of various age and size. Considering the difficulty in identifying their sex otherwise, this technique could provide a significant improvement in the veterinary care of this species. In this population, contrast radiographs showed limited accuracy for sex identification.

Demonstration of Parthenogenetic Reproduction in a Pet Ball Python (Python regius) through Analysis of Early-Stage Embryos.

Parthenogenesis is an asexual form of reproduction, normally present in various animal and plant species, in which an embryo is generated from a single gamete. Currently, there are some species for which parthenogenesis is supposed but not confirmed, and the mechanisms that activate it are not well understood. A 10-year-old, wild-caught female ball python (Python regius) laid four eggs without any prior contact with a male. The eggs were not incubated and, after 3 days, were submitted to the University of Parma for analysis due to the suspicion of potential embryo presence. Examination of the egg content revealed residual blood vessels and a small red spot, indicative of an early-stage embryo. DNA was extracted from the three deceased embryos and from the mother's blood, five microsatellites were analyzed to ascertain the origin of the embryos. The captive history data, together with the genetic microsatellite analysis approach, demonstrated the parthenogenetic origin of all three embryos. The embryos were homozygous for each of the maternal microsatellites, suggesting a terminal fusion automixis mode of development.

Egg Removal via Cloacoscopy in Three Dystocic Leopard Geckos (Eublepharis macularius).

Dystocia is a multifactorial, life-threatening condition commonly affecting pet reptiles. Treatment for dystocia can be either medical or surgical. Medical treatment usually involves the administration of oxytocin, but in some species or, in some cases, this treatment does not work as expected. Surgical treatments such as ovariectomy or ovariosalpingectomy are resolutive, but invasive in small-sized reptiles. In this paper, we describe three cases of post ovulatory egg retention in three leopard geckos (Eublepharis macularius) successfully treated through a cloacoscopic removal of the retained eggs, after a non resolutive medical treatment. The intervention was fast, non-invasive, and no procedure-related adverse effects were noted. The problem relapsed six months later in one animal, and a successful bilateral ovariosalpingectomy was performed. Cloacoscopy should be considered a valuable, non-invasive tool for egg removal in dystocic leopard geckos when the egg is accessible to manipulation. Recrudescence or complications such as adhesions, oviductal rupture, or the presence of ectopic eggs should recommend surgical intervention.

Sex Determination in Immature Sierra Nevada Lizard (Timon nevadensis).

Sex determination has a fundamental role in a captive breeding context, both for commercial reasons and in relation to animal welfare itself. However, this can be particularly difficult, especially in reptiles with little or no sexual dimorphism. Twenty-three clinically healthy young Sierra Nevada lizards (Timon nevadensis) were included in this study for sex determination. The first attempt at sexing was carried out by cloacal probing. A small, buttoned probe was inserted very gently into the hemipenal pouches, and the length of the inserted part was evaluated and measured. Subsequently, for each animal, a contrast medium was administered into the cloaca, and radiography was performed within 5 min. Through probing, 11 males and 8 females were recognized. The test was, however, equivocal in four subjects. In contrast radiography, 14 males and 9 females were identified. All the animals were rechecked after 8 months through an ultrasound examination, confirming 15 of the 14 previously male sexed animals based on contrast radiography. All the animals identified as female (n = 9) by contrast radiography were confirmed. From these results, it seems that contrast radiography may have major sensitivity in sex determination compared to probing. This technique could represent a valid and less invasive aid for sexing young lizards.

Causes of Raptor Admission to the Wildlife Rehabilitation Centre in Abruzzo (Central Italy) from 2005-2016.

The purpose of this retrospective study was to describe the causes of morbidity and mortality in free-ranging raptors admitted to a wildlife rehabilitation center (WRC) in Abruzzo Italy from 2005 to 2016 and the associated risk factors. A total of 2496 free-ranging raptors were included in the study. We analyzed the raptors' medical records, epidemiological information, bird characteristics, cause of admission, final diagnosis, and outcome. The prevalence rates of nocturnal and diurnal raptors were 49% and 51%, respectively. Nocturnal raptors showed trauma as the primary cause of admission (45.8%, 558/1219), followed by nestling (including birds on their first flight attempt or presumed abandoned by their parents) (39.2%, 478/1219), and starvation (5.6%, 68/1219). Diurnal raptors showed trauma (73.1%, 934/1277), starvation (12.1%, 155/1277), and nestling (5.8%, 74/1277) accordingly. A description of the dangers for wild birds of prey in the Abruzzo region was provided to assist in the planning of rescue and rehabilitation activities in the WRC. Finally, the cause of admission, GAP, and BCS can be used as prognostic factors during the bird entry process.

First case of systemic fatal mycobacteriosis caused by Mycobacterium goodii in a pet Kenyan sand boa (Eryx colubrinus loveridgei).

BACKGROUND: Environmental nontuberculous mycobacteria species that are not members of the M. tuberculosis complex, are ordinary inhabitants of a wide variety of environmental reservoirs and their role in human and animal diseases has been fully recognized. Even if spontaneous mycobacterial infections have been reported in a wide variety of reptiles, this is the first report of systemic fatal mycobacteriosis sustained by Mycobacterium goodii in a pet reptile.  CASE PRESENTATION: An adult, wild caught (WC), male Kenyan sand boa (Eryx colubrinus loveridgei) age unknown, was presented for clinical examination due to decreased activity level, decreased appetite and diarrhea. Blood tests showed unreliable results. Coprologic exam showed a moderate to severe presence of flagellates. X rays and ultrasound showed moderate presence of air and faeces in the large intestine. The snake was hospitalized and oral metronidazole was chosen as antiprotozoal agent in association with subcutaneous warm fluids. The snake was discharged after 2 weeks therapy in good clinical condition. Faecal exam resulted negative. One month after, the snake was quickly hospitalized again because of a recrudescence of symptoms. Biochemistry showed severe increase of AST, ALT and biliary acids. Severe leucocytosis and moderate to severe anemia were highlighted. Ultrasound examination revealed a severe diffused alteration of the liver parenchyma and a fine needle aspiration was performed. The cytological diagnosis was mixed inflammation, with a numerous of unstained rod-shaped bacteria both inside macrophages and free in the sample. The snake's condition rapidly deteriorated and euthanasia was performed. The histology of the coelomic organs confirmed a systemic mycobacteriosis. Real-time PCR identified the mycobacteria as Mycobacterium goodii. CONCLUSIONS: Species from the genus Mycobacterium are among the most important micro-organism including the causative agents of tuberculosis. Even if the general incidence of disease in reptiles due to mycobacteria is comparatively low, they can serve as reservoirs of many ubiquitous mycobacteria species. Mycobacterium goodii is a rapidly growing non-tuberculous mycobacterium that has recently been associated with severe infections in animals and humans. Although in this case the pathogenesis was not completely clear, we highlight the zoonotic risk of mycobacteriosis in exotic animals especially in WC specimens.

Evaluation of Biochemical Composition of Amniotic and Allantoic Fluids at Different Stages of Pregnancy in Queens.

Fetal fluid contents have functions in protecting fetuses and are essential for fetal development and maturation. However, little is known about the exact physiological functions of fetal fluids in fetal development, as well as the changing composition throughout the gestational period in cats. In this study, the biochemical composition of amniotic (AMN) and allantoic (ALL) fluids was investigated, as well as in the maternal serum of pregnant queens. Eighteen queens were included in this study and assigned to six different groups, D20, D25, D30, D40, D45 and D60, according to the gestational stage of fetal development. A total of 44 amniotic and 37 allantoic samples were collected. Fetal fluids contained lesser concentrations of alanine aminotransferase, albumin, cholesterol, triglycerides, creatine kinase, amylase, total protein and globulin than maternal serum. Other variables, such as aspartate aminotransferase, gamma-glutamyl transferase, bilirubin and alkaline phosphatase, were in different concentrations at specific stages of gestation when compared to maternal serum. There were no differences between fetal fluids and maternal serum for lactate dehydrogenase, urea, lipase or glucose concentrations. There were greater concentrations of creatinine in amniotic fluid than in allantoic fluid or maternal serum. Based on the results of this study, fetal fluids do not accumulate as a result of the simple filtration of maternal blood, but rather, the fetus produces many of these components as a consequence of organ development and maturation.

Concomitant Congenital Diaphagmatic Hernia (CDH) and bilateral bacterial glomerulonephritis in a pet chinchilla (Chinchilla lanigera).

BACKGROUND: The domestic chinchilla has been descended from Chinchilla lanigera (long-tailed Chinchilla) or Chinchilla chinchilla (short-tailed Chinchilla). Both species of chinchilla are currently listed as endangered by the IUCN Red List of Threatened Species. Over the past 20 years, they have spread as pets and overall knowledge about their care is improving. The present case report describes a congenital diaphragmatic hernia in a Chinchilla lanigera. CASE PRESENTATION: A 1-year-old, 420 g female chinchilla (Chinchilla lanigera) was presented for clinical examination due to 2 days haematuria episodes and anorexia. A complete haematological analysis was performed, showing a moderate neutrophilia and severe renal involvement. X-rays showed severe intestinal meteorism affecting mostly the cecum, and a soft tissue density mass with translucent areas located in the caudal thorax, making it hard to distinguish the cardiac silhouette. A barium swallow (barium sulfate) was performed and after 20 min, radiograms were performed again, showing part of the stomach dislocated in thorax. Ultrasound was also carried out, confirming the partial stomach herniation into the thoracic cavity and a severe nephropathy. The patient was euthanized according to the owner's wish and a complete necropsy was performed. The diagnosis was congenital diaphragmatic hernia concomitant to a severe bilateral bacterial glomerulonephritis. DISCUSSION AND CONCLUSIONS: Diaphragmatic hernias can be either congenital or acquired. About CDHs in pet chinchillas, literature is still lacking. In this patient there was no history of previous traumas. No scar tissue or thickening involved margins of the pathological diaphragm window at the necropsy, supporting the hypothesis of a congenital defect. Glomerulonephritis most often results from immune-mediated mechanisms, generally after the deposition of soluble immune complexes within the glomeruli. This mechanism is favoured by a prolonged antigenemia that could occur during specific viral infections, chronic bacterial infections, chronic parasitism, autoimmune diseases and neoplasia. Few cases of nephritis are described in chinchillas (Chinchilla lanigera), mostly related to bacterial sepsis or less commonly involving fungi. The evidence of bacterial aggregates in kidneys at the histopathology, confirmed the infective aetiology. No relationship between the diaphragmatic hernia and glomerulonephritis was found in this report.

Monitoring of the Reproductive Cycle in Captive-Bred Female Boa constrictor: Preliminary Ultrasound Observations.

The Boa constrictor is one of the most common reptiles bred in captivity. To achieve a successful breeding season, thorough knowledge of the females' reproductive activity is necessary. In this regard, information on the Boa constrictor is still rather scarce. The aim of the present study was to monitor the ovarian activity and the embryonic development of boas by ultrasound. We performed brief scans on thirty non-anaesthetized snakes using a portable ultrasound system and a 7.5-10 MHz linear array transducer (Esaote MyLab™ Classic). Ultrasound features, dimensions, and echogenicity of the preovulatory and postovulatory follicles were determined. As gestation progresses, the postovulatory follicle size increases, and the embryonic silhouette becomes increasingly recognizable. During the second month after ovulation, by using color Doppler, early embryos' heart activity could be evaluated. It is possible to highlight vascular connections between the mother and the membrane covering the embryonic structures. Ultrasound also allows one to identify follicular regression or slugs (nonfertilized eggs) early. The present study suggests that ultrasound could be an excellent noninvasive technique to evaluate the reproductive activity of Boa constrictor, allowing us to precisely identify the correct time for mating, monitor embryo development and viability, and allow the early diagnosis of follicular regression.

Klebsiella sp.-related infectious spondylitis in a bearded dragon (Pogona vitticeps).

BACKGROUND: Spondylitis is an inflammation of the vertebrae that leads to a destructive process with exuberant new bone formation. Osteomyelitis can produce a distortion of the bone architecture, degenerative joint changes and ankyloses of adjacent vertebrae. In reptiles, intervertebral discs are absent, so the term discospondylitis is not used. In lizards, vertebral lesions have not been well studied. The present paper describes the first case of Klebsiella sp.-related spondylitis in a pet lizard (Pogona vitticeps). CASE PRESENTATION: A 2-year-old, female bearded dragon (Pogona vitticeps) was presented for clinical examination due to a decreased activity level, decreased appetite and constipation. Blood tests showed no remarkable alterations. The haemogram showed normal parameters with relative lymphocytosis, although the absolute number of lymphocytes did not differ from the reference values. A computed tomography scan revealed a mixed osteolytic-proliferative bone lesion diffusing to the first and last tracts of the pre-sacral vertebrae together. A small amount of material obtained from the spinal swelling was sampled with an aseptic technique for bacterial culture, which was positive for Klebsiella sp. The antibiogram revealed sensitivity to enrofloxacin, marbofloxacin, and chloramphenicol and intermediate sensitivity to gentamicin. Complete return to spontaneous feeding was achieved 15 days after the beginning of antibiotic and anti-inflammatory therapy. CONCLUSIONS: In veterinary medicine, spondylitis represents a well-known disease in small companion animals. In mammals, the most common aetiologic agents are fungi and bacteria. Antibiotic therapy was set based on the antibiogram, and marbofloxacin was chosen at a dosage of 10 mg/kg subcutaneously (SC) once per day (SID). After only 7 days of antibiotic therapy, the clinical condition improved significantly; the patient started feeding and drinking spontaneously and gained weight. This case should remind clinicians of the importance of always performing antibiograms before choosing any antibiotic therapy. Considering reptiles, there have been few papers about spinal diseases, mostly regarding snakes and a few about Iguana iguana. Relative to other species of saurians, the literature remains lacking.

Determination of Efficacy of Single and Double 4.7 mg Deslorelin Acetate Implant on the Reproductive Activity of Female Pond Sliders (Trachemys scripta).

The use of long-acting gonadotropin-releasing hormone (GnRH) agonists to suppress fertility has been poorly investigated in reptiles, and the few available studies show inconsistent results. The efficacy of single and double intramuscular 4.7 mg deslorelin acetate implants in captive pond sliders (Trachemys scripta) was investigated, with 20 animals divided into three groups: a single-implant group (6 animals), a double-implant group (6 animals), and a control group (no implant). During one reproductive season (March to October), plasmatic concentration of sexual hormones (estradiol, progesterone, and testosterone) and ovarian morphometric activity via computed tomography were monitored about every 30 days. A significative decrease in the number of phase II ovarian follicles was detected in the double-implant group compared with the control group, but no significant difference was noted in the number of phase III and phase IV follicles, egg production, and plasmatic concentration of sexual hormones. Results show that neither a single nor a double deslorelin acetate implant can successfully inhibit reproduction in female pond sliders during the ongoing season, but the lower number of phase II follicles in the double-implant group can possibly be associated with reduced fertility in the following seasons.

Cytobrushing of the oral mucosa as a possible tool for early detection of testudinid herpesvirus in Horsfield's tortoises with nonspecific clinical signs.

Forty-five Horsfield's tortoises (Testudo horsfieldii; syn. Agrionemys horfieldii, Russian tortoise) belonging to different owners had decreased appetite and respiratory issues. Twenty-nine tortoises had epiphora, dyspnea, and white necrotic diphtheroid oral plaques (group G1). Ten of the remaining 16 tortoises had serious dehydration, appetite disorder, and depression (G2). The last 6 tortoises had only decreased appetite and moderate conjunctival discharge (G3). During the physical examination of all 45 tortoises, a cytologic sample and an oral swab for herpesvirus and Mycoplasma agassizii PCR testing were taken. In 20 of 29 specimens from G1, in 8 of 16 from G2, and 0 of 6 from G3, the cytologic exam revealed intranuclear acidophilic inclusion bodies, multinucleate cellular syncytia, and further abnormalities caused by herpesviral infection. Moreover, all 45 tested subjects were found to be positive for testudinid herpesvirus 1; 2 were positive for M. agassizii. This prospective study suggests that Horsfield's tortoises with such signs would benefit from this screening procedure, given that it was effective in a significant proportion of infected and symptomatic animals, and no negative effects were seen.

Studying Natural Buckyballs and Buckybowls in Fossil Materials.

Buckyballs (fullerenes) were first reported over 30 years ago, but still little is known regarding their natural occurrence, since they have so far only been found at sites of high-energy incidents, such as lightning strikes or meteor impacts, but have not been reported in low-energy materials like fossil fuels. Using ultrahigh-resolution mass spectrometry, a wide range of fullerenes from C30 to C114 was detected in the asphaltene fraction of a heavy crude oil, together with their building blocks of C10n H10 stoichiometry. High-level DLPNO-CCSD(T) calculations corroborate their stability as spherical and hemispherical species. Interestingly, the maximum intensity of the fullerenes was found at C40 instead of the major fullerene C60 . Hence, experimental evidence supported by calculations show the existence of not only buckyballs but also buckybowls as 3-dimensional polyaromatic compounds in fossil materials.

Acute tea tree oil intoxication in a pet cockatiel (Nymphicus hollandicus): a case report.

BACKGROUND: Phytotherapy is becoming a more and more common practice, not only for personal care but also for pet care. Nevertheless, we often have to deal with substances on which, in most cases, very little literature is available, even more so if the species of interest are the exotic ones. In particular, the essential oil from the Melaleuca leaves, because of its antinflammatory and antibacterial properties, is widely used and very little is known about its potential toxicity on pet birds. The present paper describes the first case of Tea tree oil intoxication in a pet bird. CASE PRESENTATION: A one-year-old, 80 g male cockatiel (Nymphicus hollandicus) was presented for clinical examination due to a serious despondency episode after the application of 3 drops of tea tree oil (Melaleuca alternifoglia) directly on the cutis of its right wing. The subject was urgently hospitalized and blood tests were performed.Serum biochemical values showed severe liver damage and slight renal involvement, complete blood count (CBC) parameters indicated a moderate neutrophilia a moderate neutropenia. Warm subcutaneous fluids and vitamin (VIT) B12 were administered, and after 8 h of fluid therapy the clinical condition of the patient improved. The subject was discharged after 48 h of hospitalization, in stable conditions. CONCLUSIONS: Toxicosis are relatively common in bird pets and a number of cases are reported in literature, concerning heavy metals intoxications and toxic plants ingestion. However, in literature there are no described cases regarding Melaleuca oil intoxication in pet birds, but it has been reported in humans (mainly by ingestion) as well as in dogs, cats and rats. We hope that this first case report can be an initial aid in the knowledge of this potential toxicosis and therefore in the clinical veterinary practice of pet birds.

Studying the fragmentation mechanism of selected components present in crude oil by collision-induced dissociation mass spectrometry.

RATIONALE: Structural characterization of individual compounds in very complex mixtures is difficult to achieve. One important step in structural elucidation is understanding the mass spectrometric fragmentation mechanisms of the compounds present in such mixtures. Here, different individual compounds presumed to be present in a complex crude oil mixture have been synthesized and structurally characterized by tandem mass spectrometry (MS/MS) studies. METHODS: Model compounds with different aromatic cores and various substitutents were synthesized. Major effort has been put into producing isomerically pure compounds to better understand the fragmentation pattern. Each synthesized compound has been subjected to MSn studies using either a triple quadrupole or a linear ion trap mass spectrometer with electrospray or atmospheric pressure photoionization. The results are used to analyze individual compounds from a complex vacuum gas oil (VGO). RESULTS: The synthesized compounds and a chromatographically simplified vacuum gas oil were used for structural analysis. The major fragmentation mechanism is the benzylic cleavage of the aliphatic side chain. Each side chain can be separately removed from the aromatic core by using MSn methods. At the end of a series of fragmentations, the base aromatic core structure remains and can be chararcterized. CONCLUSIONS: By defining the fragmentation mechanism in complex oil samples it was possible to structurally characterize individual compounds present in a chromatographically simplified VGO. The compounds consist of an aromatic core with aliphatic side chains. Cleavage of all side chains can be achieved by MSn measurements, allowing characterization of the remaining core structure.

Quantitative and Qualitative Analysis of Three Classes of Sulfur Compounds in Crude Oil.

Owing to the environmental hazards arising from sulfur-containing combustion products, strong legal regulations exist to reduce the sulfur content of transportation fuels down to a few ppm. With the ongoing depletion of low-sulfur crude oil reservoirs, increased technological efforts are needed for crude oil refining to meet these requirements. The desulfurization step is a critical part of the refining process but partly suffers from the recalcitrance of certain species to sulfur removal and the inability to quantitatively understand the behavior of individual compound classes during the process. We herein present a new and simple approach for the parallel quantification of three different classes of sulfur species present in crude oils by LC separation and on-line detection and quantification by ICP-MS/MS. This approach will help to estimate the amount of recalcitrant species and thus facilitate the optimization of desulfurization conditions during fuel production.