Use Of Gas Chromatography Research Articles

Investigating Distinct Skin Microbial Communities and Skin Metabolome Profiles in Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder influenced by genetic predisposition, environmental factors, immune dysregulation, and skin barrier dysfunction. The skin microbiome and metabolome play crucial roles in modulating the skin's immune environment and integrity. However, their specific contributions to AD remain unclear. We aimed to investigate the distinct skin microbial communities and skin metabolic compounds in AD patients compared to healthy controls (HCs). Seven patients with AD patients and seven HCs were enrolled, from whom skin samples were obtained for examination. The study involved 16S rRNA metagenomic sequencing and bioinformatics analysis as well as the use of gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) to detect metabolites associated with AD in the skin. We observed significant differences in microbial diversity between lesional and non-lesional skin of AD patients and HCs. Staphylococcus overgrowth was prominent in AD lesions, while Cutibacterium levels were decreased. Metabolomic analysis revealed elevated levels of several metabolites, including hypoxanthine and glycerol-3-phosphate in AD lesions, indicating perturbations in purine metabolism and energy production pathways. Moreover, we found a positive correlation between hypoxanthine and glycerol-3-phosphate and clinical severity of AD and Staphylococcus overgrowth. These findings suggest potential biomarkers for monitoring AD severity. Further research is needed to elucidate the causal relationships between microbial dysbiosis, metabolic alterations, and AD progression, paving the way for targeted therapeutic interventions.

Far Infrared/Terahertz Spectroscopy as a Complementary Method for the Analysis of the Spectral Features of Thymol and Carvacrol Structural Isomers

Objective: The conventional method for the characterization of volatile compounds has been mostly limited to the use of gas chromatography. This work offers an alternative method to address the limitations that might be encountered with the use of the gas chromatography method. Furthermore, this work addresses the scarcity of the analysis of these materials in the far infrared/terahertz region as previous studies have been focused mainly on the mid-infrared region. Methods: The far infrared/terahertz spectra of carvacrol and thymol were analyzed using the Fourier transform infrared (FTIR) and gas chromatography-mass spectroscopy (GC-MS). Density function theory (DFT) calculations were employed for the interpretation of the FTIR experimental spectra. Results: Thymol and carvacrol spectra were characterized by distinct absorption bands in the 200-600 cm−1 (6-18 THz). There were appearances of bands at similar energies for these isomers. These bands appeared at 320.7 cm−1 (9.6 THz), 439.2 cm−1 (13.2 THz), 525.2 cm−1 (15.8 THz), and 586.8 cm−1 (17.6 THz) for thymol and at 313.6 cm−1 (9.4 THz), 419.8 cm−1 (12.6 THz), 521.2 cm−1 (15.7 THz), and 566.9 cm−1 (17.0 THz) for carvacrol. Despite these similarities, there were also significant differences in the spectra of these materials. The theoretical peak frequencies were in agreement with the experimental absorption band frequencies. Two seemingly common absorption bands were observed in the spectra of thymol and carvacrol. However, peak assignments revealed that these bands have different vibrational modes. The GC-MS results show that the retention time of thymol and carvacrol are very close at 18.5 and 18.8 respectively. Conclusion: This work underscores the ability of far infrared/terahertz waves in identifying materials with similar structural features. Furthermore, it supplements the limited studies of these isomers in the far infrared/terahertz region. The GC-MS results emphasize the need for a complementary method that can improve the characterization of these materials.

Phytochemical Screening and Gas Chromatography-Mass Spectrometry Analysis of Bioactive Compounds Present in Stem Bark of <i>Picralima nitida </i>(stapf)

Over the years, traditional societies and ethnic nationalities have engaged plants with medicinal properties for the treatment of a range of diseases without any scientific knowledge of it inherent bioactive compounds that are responsible for its medicinal and pharmacological potentials. The aim of this study is to screen for the presence of phytochemical constituents and to identify the bioactive compounds domicile in the stem bark of <i>Picralima nitida </i>by the use of Gas Chromatography - Mass Spectrometry. The result of the quantitative investigation of the stem bark extract of <i>P. nitida</i> showed the presence of some phytochemical compounds such as saponins (3.22%), alkaloids (2.43%), flavonoids (6.05%) tannins (6.25%), oxalate (12.70%), phytate (2.87%), anthracene glycosides (2.14%) and cyanogenic glycosides (1.37%). Eleven (11) different bioactive compounds were recognized in the stem bark extract of <i>P. nitida</i> by Gas Chromatography - Mass Spectrometry analysis. The percentage of major bioactive compounds were vitamin E (69.31%), Cis-Myrtanol (5.57%), Octadecanoic acid methyl ester (4.52%), 11-Octadecenoic acid methyl ester (4.42%), 9-Methyl-2-phenyl-9H-imidazo (1,2-a) benzimidazole (3.70%), Pentadecanoic acid 14-methyl- methylester (3.21%) and 7,9-Dimethyl-6H-Indolo (2,3-b) quinoxaline (3.11%). From these findings, it could be concluded that <i>P. nitida </i>stem bark is rich in various bioactive compounds which possess antioxidant, laxative and other diverse medicinal properties. Therefore, it can be recommended as a plant of phytomedicinal value.

Клинический случай аргинин-янтарной ацидурии у новорожденного

Aim. To present a clinical case of the development of arginine-succinic aciduria (AYAA) of a newborn. Key points. The main aspects of the clinical performance, diagnosis, as well as the principles of treatment of AYAA are considered. The incidence of ANA is 1 case per 70 000 newborns. The cause is a defect in the enzyme arginine succinathy lyase, accompanied by the accumulation of toxic metabolites. The authors focused on the development of clinical symptoms of the patient. Using specialized diagnostic methods — gas chromatography and tandem mass spectrometry, as well as the method of mass parallel sequencing, despite the therapy, led to death. Conclusion. This clinical case demonstrates the importance of early diagnosis of patients with congenital metabolic disorders. It should be remembered that AYAA is a congenital defect, which can be diagnosed by clinical symptoms and the use of gas chromatography, tandem mass spectrometry, and mass parallel sequencing. Keywords: arginine-succinic aciduria, tandem-mass spectrometry, mass parallel sequencing, newborn.

The use of gas chromatography for determining pharmaceutical residues in clinical, cosmetic, food and environmental samples in the light of the requirements of sustainable development

The use of gas chromatography for determining pharmaceutical residues in clinical, cosmetic, food and environmental samples in the light of the requirements of sustainable development

Experimental study on tar formation during underground coal gasification: Effect of coal rank and gasification pressure on tar yield and chemical composition

The yield and composition of tar depending on coal rank and pressure during underground coal gasification (UCG) were studied. Two coals were used in a series of ex-situ UCG experiments: a Welsh semi-anthracite (Six Feet) and a Polish bituminous coal (Wesoła). Four high-pressure gasification trials under two distinct pressure regimes (20 and 40 bar) were conducted. The tar samples were collected directly from the reactor outlet. The following groups of compounds were analysed by use of gas chromatography (GC-MS): light monoaromatic hydrocarbons (BTEX – benzene, toluene, ethylbenzene and xylenes), polycyclic aromatic hydrocarbons (PAHs) and phenols. A series of gasification experiments revealed significant differences in tar yields and composition depending on the coal rank and gasification pressure. Significant decreases in tar contents were observed with the increase in gasification pressure from 20 to 40 bar for both coals. The total yields of the analysed tar components per kg of gasified coal were 2.58 g and 0.41 g for the experiments conducted on the Six Feet samples at 20 bar and 40 bar, respectively. The corresponding values for the Wesoła coal amounted to 5.48 g and 0.95 g. In all experiments, BTEX was a dominant group of tar components, constituting 69–86 % of the total tar yield within the tested range of compounds. The present study further proves that gasification pressure has a significant effect on the chemical composition of the produced UCG tars for both coal samples under study.

Hydromethanolic leaves extract of Dalbergia sissoo Roxb. ex DC. induces apoptosis in lung adenocarcinoma cells

Plants have a wide range of active secondary metabolites that are frequently utilized to treat cancer. For the research, Dalbergia sissoo Roxb. ex DC. leaves (DS) were hydromethanolically extracted, and their phytochemical content was determined. Total phenolics and flavonoids were quantified along with the measurement of in vitro antioxidant and cytotoxic activities. The bioactive components in the extract were identified with the use of Gas Chromatography with High-Resolution Mass Spectrometry (GC-HRMS). The crude extract contained 177.500 ± 0.019 mg/ml of flavonoids and 296.122 ± 0.002 mg/ml of Gallic Acid Equivalent (GAE) phenolics. Moreover, plant crude extract showed significant 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity (IC50, 14.06 ± 0.18 μg/ml), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) [ABTS] activity (IC50, 25.97 ± 1.04 μg/ml), superoxide scavenging activity (IC50, 149.91 ± 0.39 μg/ml), and hydrogen peroxide scavenging activity (IC50, 133.37 ± 2.30 μg/ml). The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) methods were used to confirm the presence of phenolic compounds. DS effectively scavenges nitric oxide. The crude extract of DS exhibited good cytotoxic effects on lung cancer cells (A549) with an IC50 value of 90.56 ± 2.32 (μg/ml), and less toxicity on normal lung cells (WI-38) with an IC50 value of 381.10 ± 1.58 (μg/ml). IC50 value of methotrexate (the standard drug) was 10.20 ± 1.82 μg/ml on A549 cells and 26.21 ± 1.14 μg/ml on WI-38 cells. Various staining techniques [4, 6-diamidino-2-phenylindole (DAPI), Acridine orange/Ethidium Bromide (AO/EB) staining, Giemsa staining] were used to determine the plausible mechanism of DS to induce apoptosis. The inhibiting mechanism of the crude extract was further demonstrated by the clonogenic assay and qualitative and quantitative measurements of Reactive Oxygen Species (ROS). Real-time polymerase chain reaction (RT-PCR) analysis revealed the induction of apoptosis in A549 cells through the activation of caspases 9 and 3 together with TRAIL receptors. In a nutshell, hydromethanolic extract of DS resulted in distinct apoptotic morphological alterations, ROS production, the initiation of apoptosis via activating the TRAIL receptors, caspase 9 and 3, and the suppression of colony formation in A549 cells.

2,6-Di-tert-butylo-4-metylofenol Metoda oznaczania w powietrzu na stanowiskach pracy

2,6-Di-tert-butyl-4-methylphenol (BHT) is an organic compound belonging to the phenol group and is an odorless, white or yellowish-white crystalline powder. BHT is an antioxidant used in the production of food, animal feed, animal and vegetable oils, paints, petroleum product soaps, synthetic rubbers and plastics, among others. Worker exposure to BHT can occur during the production, processing and use of the chemical. In 2021 the Group of Experts for Chemical Agents of the Interdepartmental Commission for MAC and MAI proposed MAC value of 10 mg/m3 for BHT. The aim of this study was to develop a method for determining BHT in workplace air for occupational exposure assessment within 1/10 ÷ 2 of the proposed MAC value. The method is based on retaining the BHT present in the air on a glass fiber filter and XAD-7 sorbent, leaching the retained substance with a solution of N,N-dimethylformamide in methanol and analyzing the solution by the use of gas chromatography with flame-ionization detection. The smallest concentration of BHT that can be determined under the conditions of air sampling and performing the determination is 0.96 mg/m3 (for an air sample of 60 liters). The method for the determination of BHT is presented in the form of an analytical procedure, which is included in the appendix. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Ftalan dibutylu Metoda oznaczania w powietrzu na stanowiskach pracy

Dibutyl phthalate (DBP) is a reproductive toxicant category 1B. The purpose of the conducted research work was to develop a method for the determination of dibutyl phthalate, which will enable its determination at concentrations of 0.6 mg/m3 . The method involves trapping the aerosol of dibutyl phthalate contained in the air onto a sampler – a glass tube with XAD-2 sorbent and a glass fiber filter, its extraction with an acetone/dichloromethane mixture and chromatographic analysis of the resulting solution. The study was performed with the use of gas chromatography with a mass spectrometry (RTX-5silMS Column). Validation of the method was carried out in accordance with the requirements of the European standard PN-EN 482. The method allows for the determination of a compound in the air of the working environment in a concentration range of 0.06 mg/m3 to 1.2 mg/m3 . The method for the determination of dibutyl phthalate is presented in form of an analytical procedure, which is included in the appendix. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Gas Chromatography-Mass Spectrometric analysis and antioxidant property of leaf extracts of Chamaecrista rotundifolia

Chamaerista rotundifolia is a medicinal plant whose leaves are useful for the treatment of many diseases including cancer, diarrohea and pain. This plant is underexploited in the area of extraction and bioassays that will establish its efficacy. The aim of the present study is to determine the antibacterial and antioxidant properties as well as to analyze the chemical compositions of the extracts from the plant leaves through the use of Gas chromatography – Mass Spectrometry (GC- MS) technique. The antibacterial activity of n-hexane, chloroform, ethyl acetate, and methanol extracts of the plant was tested against six (6) strains of bacteria named Pseudominas aeruginosa, Staphylococcus aerus, Klebsiella pneumoniae, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. The extracts of the plant exhibited no significant antibacterial property on the tested organisms. The result of antioxidant activity (using 1,1-diphenyl-2-picryl hydrazy (DPPH) radical scavenging) revealed that Chamaecrista rotundifolia ethyl acetate extract has low antioxidant properties due to its high (>1164.878), and negative (< 0) Inhibition Concentration at 50% values for antioxidant. However, the methanol extract exhibited antioxidant activity with an IC50 value of 5 μg/mL, which is comparable to that of ascorbic acid, 2.55 μg/mL. The GC-MS results of this extract showed that it contains some bioactive compounds. Meanwhile, the ethyl acetate extract of the plant contains 75 chemical compounds, 4 of which are principal constituents, 6 are minor and others are trace. The chloroform extract of C. rotundifolia leaf was, however, inactive in inhibiting the growth of the bacteria as the extract also had a high inhibition value when compared with the inhibition concentration at 50%, which shows its low level of antioxidant activity. Our results of antibacterial activity were found not promising while the antioxidant activity on its own showed an interesting result that could be useful in the prevention of oxidative stress side effects and cancer related diseases.

Assessment of aflatoxin and pesticide residue in cowpea (Vigna unguiculata L. Walp.) from North Central Nigeria

Cowpea is a major staple food crop which serves as a source of protein for many Nigerians. Its production and preservation involve the application of pesticides to ensure optimum yield and prevent storage losses. The study evaluated aflatoxin and pesticide residues present in Cowpea grains obtained from retailers in major markets in six States of North Central and the Federal Capital Territory Abuja, Nigeria. The quantitative detection of pesticide residue was conducted through the use of Gas chromatography fitted with Electron Capture Detector (GC-ECD). Aflatoxin (AfB1, AfB2, AfG1 and AfG2) analysis was conducted by the use of thin layer chromatography (TLC). Twenty-three pesticide residues including organochlorine insecticides, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), fungicide (Etridiazole, chloroneb), herbicide (Simazine, atrazine) were detected in cowpea samples. Dichlorodiphenyldichloroethylene (DDE) was present in 95% of the samples while endosulfan sulfate and endosulfan II were detected in 85% of the cowpea samples. Endrin aldehyde, DDT and DDD were the least detected. Pesticides residues in cowpea grains tested ranged from 72.67 mg kg- 1 in samples from Kogi State to 159.67 mg kg-1 in samples from Plateau State which were above the allowable limits of 20 mg kg-1. Aflatoxin was below detectable limits in all the cowpea samples analyzed. The high amount of pesticide residues in the cowpea samples poses health hazards to unsuspecting cowpea consumers.

Bioactive compounds against Moniliophthora roreri (Cif & Par) identified in locally produced liquid amendments (Biols)

The use of liquid organic amendments (biols) is a common practice for farmers due to the multiple benefits in the management and production of their crops, including the control of pests and diseases. The present study analyzes the chemical composition of the pure compound C1 and fractions F2 and F3 of local biols produced in two provinces of Ecuador and their antifungal activity against Moniliophthora roreri (Cif & Par). This work incorporates the use of Gas Chromatography coupled to Mass Spectrometry (GC-MS), Nuclear Magnetic Resonance (NMR) and in vitro inhibition assays for sample analysis. C1 was identified as Mannitol. The percentage of inhibition against M. roreri in F2 and F3 was 44.37% and 8.34%, respectively; and, for C1, 28.63%. The values of the median lethal dose (LD50) obtained corroborate that the F2 fraction was the one with the highest controlling activity against the pathogen. The 1,2-benzenedicarboxylic acid diisooctyl ester compound was the main compound in F2 (30.88%) and the Pentadecanoic acid, 14-methyl-, methyl ester in F3. Finally, all compounds obtained from the biol fractions were identified and it was determined that the fermentative process was suitable for producing bioactive compounds of interest to inhibit the growth of Moniliophthora roreri.

Metabolites profiling of Ganoderma-infected oil palms rachis grown on tropical soils reveals choline phosphate and 2-oxoglutaramate as potential biomarkers in the disease detection

The use of gas chromatography–mass spectrometry (GC–MS) and multivariate statistics of principal component analysis (PCA) for metabolomics profiling of non-infected and Ganoderma boninense (G. boninense) infected oil palm rachises crude extracts grown on tropical soils have been evaluated. This combination has allowed us to quickly investigate the differences in metabolite variations between non-infected and infected oil palm. Two m/z values of biological samples from Oxisol soil Choline phosphate (184.072) and 2-Oxoglutaramate (146.0440) were found to be significantly higher in Ganoderma-infected oil palm rachis but absent in healthy samples. Another intriguing discovery is that the three m/z value of biological samples from Oxisol soils increased significantly while remaining absent in biological samples from Ultisol soil 129.066 (4-Amino-4-cyanobutanoic acid, 2-Amino-4-cyanobutanoic acid), 132.066 (5-Aminolevulinic acid) and 146.044 (2-Oxoglutaramate). By comparing healthy and Ganoderma-infected oil palm tree rachis samples, it was discovered the cluster distribution of metabolites detected to be present in between groups based on the first two components of multivariate analyses.

The use of gas chromatography – high resolution mass spectrometry for suspect screening and non-targeted analysis of per- and polyfluoroalkyl substances

This study is a workflow development for the analysis, identification, and categorization of per- and polyfluoroalkyl substances (PFAS) using gas chromatography-high resolution mass spectrometry (GC-HRMS) with non-targeted analysis (NTA) and suspect screening techniques. The behavior of various PFAS in a GC-HRMS was studied with regards to retention indices, ionization susceptibility, fragmentation patterns, etc. A custom PFAS database was constructed from 141 diverse PFAS. The database contains mass spectra from electron ionization (EI) mode, as well as MS and MS/MS spectra from positive and negative chemical ionization (PCI and NCI, respectively) modes. Common fragments of PFAS were identified across a diverse set of 141 PFAS analyzed. A workflow for suspect screening of PFAS and partially fluorinated products of incomplete combustion/destruction (PICs/PIDs) was developed which utilized both the custom PFAS database and external databases. PFAS and other fluorinated compounds were identified in both a challenge sample (designed to test the identification workflow) and incineration samples suspected to contain PFAS and fluorinated PICs/PIDs. The challenge sample resulted in a 100% true positive rate (TPR) for PFAS which were present in the custom PFAS database. Several fluorinated species were tentatively identified in the incineration samples using the developed workflow.

Use of Gas Chromatography and SPME Extraction for the Differentiation between Healthy and Paenibacillus larvae Infected Colonies of Bee Brood—Preliminary Research

Paenibacillus larvae is a deadly pathogen for bee brood, which can lead to the death of entire colonies. The presence of specific volatile organic compounds (VOCs) in the hive may be related to the occurrence of this bacterium in brood. Compositions of those volatile fractions present in healthy brood from control colonies and the brood without symptoms of infection collected from the colonies infected by P. larvae were compared using gas chromatography coupled with mass spectrometry (GC-MS) and solid phase microextraction (SPME). Among the seven compounds detected and quantified, the relative concentrations of 3-carene and limonene significantly differentiated the brood from healthy and infected colonies. Based on the ratio analysis, the samples were differentiated in terms of the number of emitted VOCs.

Analytical Platform for the Study of Metabolic Pathway of Propyl Propane Thiosulfonate (PTSO) from Allium spp.

The present work is focused on the development of an analytical platform to elucidate the metabolic pathway of PTSO from onion, an organosulfur compound well-known for its functional and technological properties and its potential application in animal and human nutrition. This analytical platform consisted of the use of gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography quadrupole with time-of-flight MS (UHPLC-Q-TOF-MS) in order to monitor volatile and non-volatile compounds derived from the PTSO. For the extraction of the compounds of interest, two different sample treatments were developed: liquid-liquid extraction (LLE) and salting-out assisted liquid-liquid extraction (SALLE) for GC-MS and UHPLC-Q-TOF-MS analysis, respectively. Once the analytical platform was optimised and validated, an in vivo study was planned to elucidate PTSO metabolisation, revealing the presence of dipropyl disulfide (DPDS) in liver samples with concentrations between 0.11 and 0.61 µg g-1. The DPDS maximum concentration in the liver was observed at 0.5 h after the intake. DPDS was also present in all plasma samples with concentrations between 2.1 and 2.4 µg mL-1. In regard to PTSO, it was only found in plasma at times above 5 h (0.18 µg mL-1). Both PTSO and DPDS were excreted via urine 24 h after ingestion.

Bioactive compounds in ethanolic extract of <em>Strychnos innocua</em> root using gas chromatography and mass spectrometry (GC-MS)

Medicinal plants are of great relevance with endless pharmaceutical and therapeutic properties. They are source of wide array of secondary metabolites or bioactive compounds/phytochemicals (phenols, alkaloids, flavonoids, terpenoids, tannins, steroids and saponins) which are capable of discharging numerous biological functions (antimicrobial, antioxidant, antiviral, antifungal, anti-fibrotic, immune-modulatory, cytotoxic, antipyretic, antitumor, antihelminthic, antiprotozoal, antibacterial and so on). The use of gas chromatography and mass spectrometry analysis in identifying the bioactive compounds in ethanolic extract of Strychnos innocua root is a fundamental technique in quantifying the unknown samples, trace elements and contaminants leading to the discovery of novel compounds of pharmaceutical and biomedical importance. Result obtained showed that Strychnos innocua root extract contains 39 bioactive compounds with α-Cubebene (20.09%) having the highest concentration followed by Dibutyl benzene -1,2 – dicarboxylate (10.17%), β-Elemenone (10.02%), 4-Methoxy-2-nitroformanilide (7.21%), 1-Methyl cyclopropane methanol (5.96%), 1, 3 propanediol, 2-ethyl 2-hydroxymethyl (3.71%), Azelaic acid (2.87%), Glycidol stearate (2.85%), Chloromethyl 2-chlorodecanoate (2.83%) and γ-terpinene (2.56%) respectively. The remaining 29 bioactive compounds have concentrations less than 2%. It was concluded that all the compounds observed are sources of medication that can be used traditionally in the treatment of human and animal diseases.

Synthesis and Photocatalytic Activity for Toluene Removal of CDs/TiO2 - Zeolite Y

Hydrothermally synthesized carbon nanodots (CDs) were impregnated on TiO2. The product (CDs/TiO2) was mechanically mixed with zeolite Y for application in toluene photocatalytic oxidation reaction under UV radiation. Material properties of the samples were investigated by different methods. Toluene vapor was chosen as a typical volatile organic compound to investigate the performance of CDs/TiO2 – zeolite Y photocatalyst when these technological parameters were changed: toluene concentration, gas flow rate, humidity and UV light intensity. In each reaction, only one parameter was changed and the remaining conditions were fixed. The toluene concentrations at the beginning and the end of each reaction were analyzed with the use of gas chromatography (GC). The results of different reaction conditions show the trends for toluene treatment of the CDs/TiO2 – zeolite Y catalyst, thereby providing specific explanations for these trends. The experiments also show that toluene removal is highest when the toluene concentration in the inlet gas is 314 ppmv, the flow rate is 3 L/h, the humidity is 60%, and the catalyst (CDs/TiO2 – zeolite Y composite with 70% zeolite in weight) is illuminated by 4 UV lamps. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Analysis of sulfur compounds for crude oil fingerprinting using gas chromatography with sulfur chemiluminescence detector

Oil spills are a severe problem worldwide due to the resulting damage to marine and coastal ecosystems and to local economies. Identification of the source of spilled oils can be challenging, especially if the oils have undergone severe weathering. Due to their high durability, biomarker compounds (e.g. hopanes, steranes) are widely used for oil fingerprinting. Some sulfur-containing heterocyclic compounds e.g. alkylated dibenzothiophenes are also considered to be highly resistant. In this study, the use of Gas Chromatography with Sulfur Chemiluminescence Detection was investigated as a means of oil fingerprinting using the distribution the sulfur compounds in five different fresh and weathered crude oils. Chemometric analysis was also performed. The results indicate that the sulfur compounds distribution is unique for each crude oil. The distributions of the heavy sulfur compounds (i.e., C2DBTs and C3DBTs) are unchanged after weathering. Therefore, the GC-SCD technique can be considered to support the oil spill identification.

The Use of Breath Analysis in the Management of Lung Cancer: Is It Ready for Primetime?

Breath analysis is a promising non-invasive method for the detection and management of lung cancer. Exhaled breath contains a complex mixture of volatile and non-volatile organic compounds that are produced as end-products of metabolism. Several studies have explored the patterns of these compounds and have postulated that a unique breath signature is emitted in the setting of lung cancer. Most studies have evaluated the use of gas chromatography and mass spectrometry to identify these unique breath signatures. With recent advances in the field of analytical chemistry and machine learning gaseous chemical sensing and identification devices have also been created to detect patterns of odorant molecules such as volatile organic compounds. These devices offer hope for a point-of-care test in the future. Several prospective studies have also explored the presence of specific genomic aberrations in the exhaled breath of patients with lung cancer as an alternative method for molecular analysis. Despite its potential, the use of breath analysis has largely been limited to translational research due to methodological issues, the lack of standardization or validation and the paucity of large multi-center studies. It is clear however that it offers a potentially non-invasive alternative to investigations such as tumor biopsy and blood sampling.