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Archaeological resinous samples from Asian wrecks: Taxonomic characterization by GC-MS

Burger P, Charrié-Duhaut A, Connan J, Flecker M, Albrecht P

Anal Chim Acta, 2009 Aug 19;648(1):85-97.
PMID: 19616693 DOI: 10.1016/j.aca.2009.06.022

Plant resins, and particularly dammars from the Dipterocarpaceae family, were widely used in the past, notably as part of caulking material. The organic composition of resins, already complicated, is not always preserved over time and can be considerably affected by ageing. Hence, their occurrence in archaeological items leads to the necessity to identify them taxonomically with precision. Resinous organic materials collected near and/or on wrecks discovered in South China Sea, supposed to contain dammar resins because of their geographical excavation context, were investigated by gas chromatography-mass spectrometry (GC-MS), together with freshly collected dammars, to establish taxonomic and alteration parameters allowing to identify dammar even in very altered samples or in mixtures together with other organic materials. This study specially focuses on three samples collected within or close to the M1J wreck, a Portuguese wreck lost in the Straight of Malacca during the 16th century. Our analyses establish that all three are made of dammar, two of them in association with pitch and bitumen. In addition, biodegradation biomarkers were detected in all these three samples, indicating that they were submitted to microbial degradation processes during their ageing.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Degradation of DEET by ozonation in aqueous solution

Tay KS, Rahman NA, Abas MR

Chemosphere, 2009 Aug;76(9):1296-302.
PMID: 19570564 DOI: 10.1016/j.chemosphere.2009.06.007

This study was undertaken in order to understand the factors affecting the degradation of an insect repellent, N,N-diethyl-m-toluamide (DEET) by ozonation. Kinetic studies on DEET degradation were carried out under different operating conditions, such as varied ozone doses, pH values of solution, initial concentrations of DEET, and solution temperatures. The degradation of DEET by ozonation follows the pseudo-first-order kinetic model. The rate of DEET degradation increased exponentially with temperature in the range studied (20-50 degrees C) and in proportion with the dosage of ozone applied. The ozonation of DEET under different pH conditions in the presence of phosphate buffer occurred in two stages. During the first stage, the rate constant, k(obs), increased with increasing pH, whereas in the second stage, the rate constant, k(obs2), increased from pH 2.3 up to 9.9, however, it decreased when the pH value exceeded 9.9. In the case where buffers were not employed, the k(obs) were found to increase exponentially with pH from 2.5 to 9.2 and the ozonation was observed to occur in one stage. The rate of degradation decreased exponentially with the initial concentration of DEET. GC/MS analysis of the by-products from DEET degradation were identified to be N,N-diethyl-formamide, N,N-diethyl-4-methylpent-2-enamide, 4-methylhex-2-enedioic acid, N-ethyl-m-toluamide, N,N-diethyl-o-toluamide, N-acetyl-N-ethyl-m-toluamide, N-acetyl-N-ethyl-m-toluamide 2-(diethylamino)-1-m-tolylethanone and 2-(diethylcarbamoyl)-4-methylhex-2-enedioic acid. These by-products resulted from ozonation of the aliphatic chain as well as the aromatic ring of DEET during the degradation process.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Solid-phase microextraction for determining twelve orange flavour compounds in a model beverage emulsion

Mirhosseini H, Tan CP, Yusof S, Hamid NS

Phytochem Anal, 2008 Sep-Oct;19(5):429-37.
PMID: 18435528 DOI: 10.1002/pca.1068

Solid-phase microextraction (SPME) coupled to gas chromatography has been applied for the headspace analysis (HS) of 12 target flavour compounds in a model orange beverage emulsion. The main volatile flavour compounds studied were: acetaldehyde, ethyl acetate, alpha-pinene, ethyl butyrate, beta-pinene, myrcene, limonene, gamma-terpinene, octanal, decanal, linalool and citral (neral plus geranial). After screening the fibre type, the effect of other HS-SPME variables such as adsorption temperature (25-55 degrees C), extraction time (10-40 min), sample concentration (1-100% w/w), sample amount (5-10 g) and salt amount (0-30% w/w) were determined using a two-level fractional factorial design (2(5-2)) that was expanded further to a central composite design. It was found that an extraction process using a carboxen-polydimethylsiloxane fibre coating at 15 masculineC for 50 min with 5 g of diluted emulsion 1% (w/w) and 30% (w/w) of sodium chloride under stirring mode resulted in the highest HS extraction efficiency. For all volatile flavour compounds, the linearity values were accurate in the concentration ranges studied (r(2) > 0.97). Average recoveries that ranged from 90.3 to 124.8% showed a good accuracy for the optimised method. The relative standard deviation for six replicates of all volatile flavour compounds was found to be less than 15%. For all volatile flavour compounds, the limit of detection ranged from 0.20 to 1.69 mg/L.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Fulltext The effects of Secondhand Smoke (SHS) exposure on microvascular endothelial function among healthy women

Sanip Z, Hanaffi SH, Ahmad I, Yusoff SS, Rasool AH, Yusoff HM

Tob Induc Dis, 2015;13(1):32.
PMID: 26346914 DOI: 10.1186/s12971-015-0052-9

BACKGROUND: Studies have demonstrated that secondhand smoke (SHS) exposure could impair endothelial function. However, the effect of SHS exposure specifically on microvascular endothelial function is not well understood. This study aimed to determine the effects of SHS exposure on microvascular endothelial function among non-smoking, generally healthy women.
FINDINGS: We studied 127 women; and based on their hair nicotine levels measured using gas chromatography-mass spectrometry, 25 of them were categorized as having higher hair nicotine levels, 25 were grouped as having lower hair nicotine and 77 women were grouped into the non-detected group. The non-detected group did not have detectable levels of hair nicotine. Anthropometry, blood pressure (BP), lipid profile and high-sensitivity C-reactive protein (hsCRP) were measured accordingly. Microvascular endothelial function was assessed non-invasively using laser Doppler fluximetry and the process of iontophoresis involving acetylcholine and sodium nitroprusside as endothelium-dependent and endothelium-independent vasodilators respectively. The mean hair nicotine levels for higher and lower hair nicotine groups were 0.74 (1.04) and 0.05 (0.01) ng/mg respectively. There were no significant differences in anthropometry, BP, lipid profile and hsCRP between these groups. There were also no significant differences in the microvascular perfusion and endothelial function between these groups.
CONCLUSION: In this study, generally healthy non-smoking women who have higher, lower and non-detected hair nicotine levels did not show significant differences in their microvascular endothelial function. Low levels of SHS exposure among generally healthy non-smoking women may not significantly impair their microvascular endothelial function.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Fulltext Antihyperglycemic Effect of Methanol Extract of Syzygium polyanthum (Wight.) Leaf in Streptozotocin-Induced Diabetic Rats

Widyawati T, Yusoff NA, Asmawi MZ, Ahmad M

Nutrients, 2015 Sep;7(9):7764-80.
PMID: 26389944 DOI: 10.3390/nu7095365

Syzygium polyanthum (S. polyanthum), a plant belonging to Myrtaceae, is widely used in Indonesian and Malaysian cuisines. Diabetic patients in Indonesia also commonly use it as a traditional medicine. Hence, this study was conducted to investigate the antihyperglycemic effect of the methanol extract (ME) of S. polyanthum leaf and its possible mechanisms of action. To test for hypoglycemic activity, ME was administered orally to normal male Sprague Dawley rats after a 12-h fast. To further test for antihyperglycemic activity, the same treatment was administered to glucose-loaded (intraperitoneal glucose tolerance test, IPGTT) and streptozotocin (STZ)-induced diabetic rats, respectively. Hypoglycemic test in normal rats did not show significant reduction in blood glucose levels (BGLs) by the extract. Furthermore, IPGTT conducted on glucose-loaded normal rats also did not show significant reduction of BGLs. However, repeated administration of metformin and three doses of ME (250, 500 and 1000 mg/kg) for six days caused significant reduction of fasting BGLs in STZ-induced diabetic rats. The possible mechanisms of action of S. polyanthum antihyperglycemic activity were assessed by measurement of intestinal glucose absorption and glucose uptake by isolated rat abdominal muscle. It was found that the extract not only inhibited glucose absorption from the intestine but also significantly increased glucose uptake in muscle tissue. A preliminary phytochemical qualitative analysis of ME indicated the presence of tannins, glycosides, flavonoids, alkaloids and saponins. Additionally, Gas Chromatography-Mass Spectrometry (GC-MS) analysis detected squalene. In conclusion, S. polyanthum methanol leaf extract exerts its antihyperglycemic effect possibly by inhibiting glucose absorption from the intestine and promoting glucose uptake by the muscles.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Baseline distribution and sources of linear alkyl benzenes (LABs) in surface sediments from Brunei Bay, Brunei

Alkhadher SAA, Zakaria MP, Yusoff FM, Kannan N, Suratman S, Keshavarzifard M, et al.

Mar Pollut Bull, 2015 Dec 15;101(1):397-403.
PMID: 26478457 DOI: 10.1016/j.marpolbul.2015.10.011

Sewage pollution is one of major concerns of coastal and shoreline settlements in Southeast Asia, especially Brunei. The distribution and sources of LABs as sewage molecular markers were evaluated in surface sediments collected from Brunei Bay. The samples were extracted, fractionated and analyzed using gas chromatography- mass spectrometry (GC-MS). LABs concentrations ranged from 7.1 to 41.3 ng g(-1) dry weight (dw) in surficial sediments from Brunei Bay. The study results showed LABs concentrations variably due to the LABs intensity and anthropogenic influence along Brunei Bay in recent years. The ratio of Internal to External isomers (I/E ratio) of LABs in sediment samples from Brunei Bay ranged from 0.56 to 2.17 along Brunei Bay stations, indicating that the study areas were receiving primary and secondary effluents. This is the first study carried out to assess the distribution and sources of LABs in surface sediments from Brunei Bay, Brunei.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Blowfly Larval Tissues as a Secondary Detector for Determining Paraquat-Related Death in Rabbit Carcass

Lawai V, Abdul Rahim NA, Ngaini Z

J Forensic Sci, 2015 11;60(6):1620-4.
PMID: 26382214 DOI: 10.1111/1556-4029.12852

Paraquat poisoning is commonly associated with suicide or homicide in Malaysia. In a case involving advanced body decomposition, pathological analysis regarding the cause of death may become difficult or almost impossible. Insects serve as common alternative matrix for poison detection in forensic analysis. Paraquat detection via secondary bioaccumulation in fly larvae tissue has never been reported. In this study, tissues from blowfly larvae collected from a rabbit carcass with paraquat poisoning were analyzed for secondary bioaccumulation. Larvae samples were collected and analyzed using liquid-liquid extraction. The detection was performed via reduction of quaternary ammonium presence in paraquat and analyzed using gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring mode (SIM mode). GC-MS showed the elution of reduced paraquat was at retention time 12.8 min. Blowfly larvae tissue has proven useful as a secondary detector in paraquat-related deaths.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry

Vijaya Bhaskar Reddy A, Yusop Z, Jaafar J, Bin Aris A, Abdul Majid Z, Umar K, et al.

J Sep Sci, 2016 Jun;39(12):2276-83.
PMID: 27095506 DOI: 10.1002/jssc.201600155

A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid-phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C18 cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected-ion monitoring mode. Good linear relationships were obtained in the range of 0.1-50 μg/L for chlorpyrifos, and 0.05-50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54-86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Fulltext In Vitro Analysis of Metabolites Secreted during Infection of Lung Epithelial Cells by Cryptococcus neoformans

Liew KL, Jee JM, Yap I, Yong PV

PLoS One, 2016;11(4):e0153356.
PMID: 27054608 DOI: 10.1371/journal.pone.0153356

Cryptococcus neoformans is an encapsulated basidiomycetous yeast commonly associated with pigeon droppings and soil. The opportunistic pathogen infects humans through the respiratory system and the metabolic implications of C. neoformans infection have yet to be explored. Studying the metabolic profile associated with the infection could lead to the identification of important metabolites associated with pulmonary infection. Therefore, the aim of the study was to simulate cryptococcal infection at the primary site of infection, the lungs, and to identify the metabolic profile and important metabolites associated with the infection at low and high multiplicity of infections (MOI). The culture supernatant of lung epithelial cells infected with C. neoformans at MOI of 10 and 100 over a period of 18 hours were analysed using gas chromatography mass spectrometry. The metabolic profiles obtained were further analysed using multivariate analysis and the pathway analysis tool, MetaboAnalyst 2.0. Based on the results from the multivariate analyses, ten metabolites were selected as the discriminatory metabolites that were important in both the infection conditions. The pathways affected during early C. neoformans infection of lung epithelial cells were mainly the central carbon metabolism and biosynthesis of amino acids. Infection at a higher MOI led to a perturbance in the β-alanine metabolism and an increase in the secretion of pantothenic acid into the growth media. Pantothenic acid production during yeast infection has not been documented and the β-alanine metabolism as well as the pantothenate and CoA biosynthesis pathways may represent underlying metabolic pathways associated with disease progression. Our study suggested that β-alanine metabolism and the pantothenate and CoA biosynthesis pathways might be the important pathways associated with cryptococcal infection.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Fulltext Synthesis, spectroscopic and chromatographic studies of sunflower oil biodiesel using optimized base catalyzed methanolysis

Naureen R, Tariq M, Yusoff I, Chowdhury AJ, Ashraf MA

Saudi J Biol Sci, 2015 May;22(3):332-9.
PMID: 25972756 DOI: 10.1016/j.sjbs.2014.11.017

Methyl esters from vegetable oils have attracted a great deal of interest as substitute for petrodiesel to reduce dependence on imported petroleum and provide an alternate and sustainable source for fuel with more benign environmental properties. In the present study biodiesel was prepared from sunflower seed oil by transesterification by alkali-catalyzed methanolysis. The fuel properties of sunflower oil biodiesel were determined and discussed in the light of ASTM D6751 standards for biodiesel. The sunflower oil biodiesel was chemically characterized with analytical techniques like FT-IR, and NMR ((1)H and (13)C). The chemical composition of sunflower oil biodiesel was determined by GC-MS. Various fatty acid methyl esters (FAMEs) were identified by retention time data and verified by mass fragmentation patterns. The percentage conversion of triglycerides to the corresponding methyl esters determined by (1)H NMR was 87.33% which was quite in good agreement with the practically observed yield of 85.1%.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Other factors to consider in the formation of chloropropandiol fatty esters in oil processes

Ramli MR, Siew WL, Ibrahim NA, Kuntom A, Abd Razak RA

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2015;32(6):817-24.
PMID: 25798697 DOI: 10.1080/19440049.2015.1032368

This paper examines the processing steps of extracting palm oil from fresh fruit bunches in a way that may impact on the formation of chloropropandiol fatty esters (3-MCPD esters), particularly during refining. Diacylglycerols (DAGs) do not appear to be a critical factor when crude palm oils are extracted from various qualities of fruit bunches. Highly hydrolysed oils, in spite of the high free fatty acid (FFA) contents, did not show exceptionally high DAGs, and the oils did not display a higher formation of 3-MCPD esters upon heat treatment. However, acidity measured in terms of pH appears to have a strong impact on 3-MCPD ester formation in the crude oil when heated at high temperatures. The differences in the extraction process of crude palm oil from current commercial processes and that from a modified experimental process showed clearly the effect of acidity of the oil on the formation of 3-MCPD esters. This paper concludes that the washing or dilution step in palm oil mills removes the acidity of the vegetative materials and that a well-optimised dilution/washing step in the extraction process will play an important role in reducing formation of 3-MCPD esters in crude palm oil upon further heat processing.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Clean-up, detection and determination of salbutamol in human urine and serum

Saleh MI, Koh YM, Tan SC, Aishah AL

Analyst, 2000 Sep;125(9):1569-72.
PMID: 11064937

Salbutamol ¿2-(tert-butylamino)-1-[4-hydroxy-3- (hydroxymethyl)phenyl]ethanol¿, also known as albuterol, is clinically the most widely used beta 2-adrenoceptor agonist in the treatment of bronchial asthma. During this study, we evaluated liquid-liquid extraction (LLE) and solid-phase extraction (SPE) in order to develop a reliable extraction method followed by analysis using liquid chromatography and gas chromatography. An assay is described which involves SPE as the clean-up method followed by gas chromatography-mass spectrometry to determine salbutamol levels in human serum after oral administration. The SPE method requires the use of a hyper-cross-linked styrene-divinylbenzene bonded phase (ENV+) without involving any sample pre-treatment to obtain 60-65% recoveries for salbutamol and terbutaline as the internal standard. Distilled water and 1% trifluoroacetic acid in methanol were found to be the most suitable washing solvent and eluting solvent, respectively. A detection limit of 2 ng mL-1 was achieved by derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide to form trimethylsilyl (TMS)-salbutamol (m/z 369) and TMS-terbutaline (m/z 356). The relationship between the ratio of the peak area of salbutamol to that of the internal standard and concentration was linear for the range tested (2-200 ng mL-1) and the correlation of coefficient was 0.9999 with a y-intercept not significantly different from zero. The inter-day relative standard deviation (RSD) was < 10% for all three concentrations. The intra-day RSD was 14% for 2 ng mL-1. This assay was then successfully applied to human serum samples obtained from clinical trials after oral administration of salbutamol.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Four new clerodane diterpenoids from Callicarpa pentandra

Xu J, Harrison LJ, Vittal JJ, Xu YJ, Goh SH

J Nat Prod, 2000 Aug;63(8):1062-5.
PMID: 10978198

Leaf extracts of Callicarpa pentandra provided four new clerodane-type diterpenoids (1-4), of which 1, 2, and 4 have ring-A-contracted structures. Their structures and stereochemistry were established by spectral data interpretation, and for 3 also by single-crystal X-ray diffraction.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Hepatotoxic constituents in the rumen of Brachiaria decumbens intoxicated sheep

Abdullah AS, Lajis NH, Bremner JB, Davies NW, Mustapha W, Rajion MA

Vet Hum Toxicol, 1992 Apr;34(2):154-5.
PMID: 1509678

Spectroscopic examinations of purified extracts of the rumen content of sheep intoxicated by Brachiaria decumbens revealed the presence of a mixture of sapogenins, identified as 3-spirostanols. These isomeric steroid sapogenins (C27H44O3) are believed the toxic principles in causing toxicity in sheep after feeding on B. decumbens.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Biomass burning as the main source of organic aerosol particulate matter in Malaysia during haze episodes

Radzi bin Abas M, Oros DR, Simoneit BR

Chemosphere, 2004 May;55(8):1089-95.
PMID: 15050806

The haze episodes that occurred in Malaysia in September-October 1991, August-October 1994 and September-October 1997 have been attributed to suspended smoke particulate matter from biomass burning in southern Sumatra and Kalimantan, Indonesia. In the present study, polar organic compounds in aerosol particulate matter from Malaysia are converted to their trimethylsilyl derivatives and analyzed by gas chromatography-mass spectrometry in order to better assess the contribution of the biomass burning component during the haze episodes. On the basis of this analysis, levoglucosan was found to be the most abundant organic compound detected in almost all samples. The monosaccharides, alpha- and beta-mannose, the lignin breakdown products, vanillic and syringic acids and the minor steroids, cholesterol and beta-sitosterol were also present in some samples. The presence of the tracers from smoke overwhelmed the typical signatures of emissions from traffic and other anthropogenic activities in the urban areas.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Fulltext Flaxseed (linum usitatissimum) extract activity on human oral fibroblasts (HOrF) cell line

Sama Naziyah Shaban, Abdelkader Elbadawy Abbas Ashour, Khairani Idah Mokhtar, Solachuddin JauhariAriefIchwan, Basma Ezzat Mustafa Alahmad

Ann Dent, 2020;27(1):50-54.
MyJurnal

Natural products have demonstrated various activities beneficial to general health. Flaxseed (Linum usitatissimum) has been reported in many studies for its antimicrobial, antioxidant, and anti-inflammatory effects. Additionally, flaxseed extracts have skin wound healing activity and potential for treating oral ulcers.L. usitatissimum was extracted using 70% ethanol via soxhlet method and gas chromatography mass spectrum (GC-MS) was used to analyze the components of L. usitatissimum extract. The crude flaxseed oil were applied to human oral fibroblasts (HOrF), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to assess the cell viability after 24, 48 and 72 hours. Scratched HOrF cells were treated with crude flaxseed oil and healing was monitored per wound healing assay. GC-MS indicate that the major components present in L. usitatissimum oil extract are linolic, palmitic and oleic acid. L. usitatissimum crude oil extract showed high proliferation effect on HOrF cells at 24 and 48 hours, while the highest proliferation effect was recorded at 72 hours post-treatment. The wound healing assay results showed that healing activity of HOrF cells occurred as soon as 18 hours post-treatment when treated with L. usitatissimum crude oil extract. L. usitatissimum crude oil extract has proliferating and healing effects on HOrF cell line. Therefore, it can be considered as a potential promising oral wound healing agent.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Distribution, sources and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected during different monsoon seasons and haze episode in Kuala Lumpur

Sulong NA, Latif MT, Sahani M, Khan MF, Fadzil MF, Tahir NM, et al.

Chemosphere, 2019 Mar;219:1-14.
PMID: 30528968 DOI: 10.1016/j.chemosphere.2018.11.195

This study aimed to determine the distribution and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Kuala Lumpur during different monsoon seasons. The potential sources of PM2.5 were investigated using 16 priority PAHs with additional of biomass tracers namely levoglucosan (LV), mannosan (MN) and galactosan (GL). This study also investigated the cytotoxic potential of the extracted PAHs towards V79-4 cells. A high-volume air sampler (HVS) was used to collect PM2.5 samples for 24 h. PAHs were extracted using dichloromethane (DCM) while biomass tracers were extracted by a mixture of DCM/methanol (3:1) before analysis with gas chromatography-mass spectrometry (GC-MS). The cytotoxicity of the PAHs extract was determined by assessing the cell viability through the reduction of tetrazolium salts (MTT). The results showed that the total mean ± SD concentrations of PAHs during the southwest (SW) and northeast (NE) monsoons were 2.51 ± 0.93 ng m-3 and 1.37 ± 0.09 ng m-3, respectively. Positive matrix factorization (PMF) using PAH and biomass tracer concentrations suggested four potential sources of PM2.5; gasoline emissions (29.1%), natural gas and coal burning (28.3%), biomass burning (22.3%), and diesel and heavy oil combustion (20.3%). Health risk assessment showed insignificant incremental lifetime cancer risk (ILCR) of 2.40E-07 for 70 years of exposure. MTT assay suggested that PAHs extracts collected during SW monsoon have cytotoxic effect towards V79-4 cell at the concentrations of 25 μg mL-1, 50 μg mL-1, 100 μg mL-1 whereas non-cytotoxic effect was observed on the PAHs sample collected during NE monsoon.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Label-Free Time-of-Flight Secondary Ion Mass Spectrometry Imaging of Sulfur-Producing Enzymes inside Microglia Cells following Exposure to Silver Nanowires

Leo BF, Fearn S, Gonzalez-Cater D, Theodorou I, Ruenraroengsak P, Goode AE, et al.

Anal Chem, 2019 Sep 03;91(17):11098-11107.
PMID: 31310103 DOI: 10.1021/acs.analchem.9b01704

There are no methods sensitive enough to detect enzymes within cells, without the use of analyte labeling. Here we show that it is possible to detect protein ion signals of three different H2S-synthesizing enzymes inside microglia after pretreatment with silver nanowires (AgNW) using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Protein fragment ions, including the fragment of amino acid (C4H8N+ = 70 amu), fragments of the sulfur-producing cystathionine-containing enzymes, and the Ag+ ion signal could be detected without the use of any labels; the cells were mapped using the C4H8N+ amino acid fragment. Scanning electron microscopy imaging and energy-dispersive X-ray chemical analysis showed that the AgNWs were inside the same cells imaged by TOF-SIMS and transformed chemically into crystalline Ag2S within cells in which the sulfur-producing proteins were detected. The presence of these sulfur-producing cystathionine-containing enzymes within the cells was confirmed by Western blots and confocal microscopy images of fluorescently labeled antibodies against the sulfur-producing enzymes. Label-free TOF-SIMS is very promising for the label-free identification of H2S-contributing enzymes and their cellular localization in biological systems. The technique could in the future be used to identify which of these enzymes are most contributory.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
BTEX compositions and its potential health impacts in Malaysia

Latif MT, Abd Hamid HH, Ahamad F, Khan MF, Mohd Nadzir MS, Othman M, et al.

Chemosphere, 2019 Dec;237:124451.
PMID: 31394440 DOI: 10.1016/j.chemosphere.2019.124451

This study aims to determine the composition of BTEX (benzene, toluene, ethylbenzene and xylene) and assess the risk to health at different sites in Malaysia. Continuous monitoring of BTEX in Kuala Lumpur City Centre, Kuala Terengganu, Kota Kinabalu and Fraser Hill were conducted using Online Gas Chromatograph. For comparison, BTEX at selected hotspot locations were determined by active sampling method using sorbent tubes and Thermal Desorption Gas Chromatography Mass Spectrometry. The hazard quotient (HQ) for non-carcinogenic and the life-time cancer risk (LTCR) of BTEX were calculated using the United States Environmental Protection Agency (USEPA) health risk assessment (HRA) methods. The results showed that the highest total BTEX concentrations using continuous monitoring were recorded in the Kuala Lumpur City Centre (49.56 ± 23.71 μg/m3). Toluene was the most dominant among the BTEX compounds. The average concentrations of benzene ranged from 0.69 ± 0.45 μg/m3 to 6.20 ± 3.51 μg/m3. Measurements using active sampling showed that BTEX concentrations dominated at the roadside (193.11 ± 114.57 μg/m3) in comparison to petrol station (73.08 ± 30.41 μg/m3), petrochemical industry (32.10 ± 13.13 μg/m3) and airport (25.30 ± 6.17 μg/m3). Strong correlations among BTEX compounds (p<0.01, r>0.7) at Kuala Lumpur City Centre showed that BTEX compounds originated from similar sources. The values of HQ at all stations were <1 indicating the non-carcinogenic risk are negligible and do not pose threats to human health. The LTCR value based on benzene inhalation (1.59 × 10-5) at Kuala Lumpur City Centre were between 1 × 10-4 and 1 × 10-5, representing a probable carcinogenic risk.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry
GC-MS analysis of metabolites from soxhlet extraction, ultrasound-assisted extraction and supercritical fluid extraction of Salacca zalacca flesh and its alpha-glucosidase inhibitory activity

Saleh MSM, Bukhari DAM, Siddiqui MJA, Kasmuri AR, Murugesu S, Khatib A

Nat Prod Res, 2020 May;34(9):1341-1344.
PMID: 30678487 DOI: 10.1080/14786419.2018.1560295

Different extraction processes were employed to extract bioactive metabolites from Salacca zalacca flesh by a range of aqueous and organic solvents. The highest extraction yield was obtained by 50% ethanol extract of SE (73.18 ± 4.35%), whereas SFE_1 showed the lowest yield (0.42 ± 0.08%). All extracts were evaluated for in vitro α-glucosidase inhibitory activity, measured by their IC50 values in comparison to that of quercetin, the positive control (IC50 = 2.7 ± 0.7 μg/mL). The lowest α-glucosidase inhibitory activity was indicated by water extract of SE (IC50 = 724.3 ± 42.9 μg/mL) and the highest activity was demonstrated by 60% ethanol extract by UAE (IC50 = 16.2 ± 2.4 μg/mL). All extracts were analysed by GC-MS and identified metabolites like carbohydrates, fatty acids, organic acids, phenolic acids, sterols and alkane-based compounds etcetera that may possess the potential as α-glucosidase inhibitor and may attribute to the α-glucosidase inhibitory activity.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry

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