Volatile organic compounds in honey are known for their considerable impact on the organoleptic properties of honey, such as aroma, flavor, taste, and texture. The type and composition of volatile organic compounds are influenced by entomological, geographical, and botanical origins; thus, these compounds have the potential to be chemical markers. Sixty-two volatile compounds were identified using gas chromatography-mass spectrometry from 30 Heterotrigona itama (H. itama) honey samples from 3 different geographical origins. Hydrocarbons and benzene derivatives were the dominant classes of volatile organic compounds in the samples. Both clustering and discriminant analyses demonstrated a clear separation between samples from distant origins (Kedah and Perak), and the volcano plot supported it. The reliability and predictability of the partial least squares-discriminant analysis model from the discriminant analysis were validated using cross-validation (R2 : 0.93; Q2 : 0.83; accuracy: 0.97) and the permutation test (p 1.0) and the Kruskal-Wallis test (p
Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods
Produced water or oilfield wastewater is the largest volume ofa waste stream associated with oil and gas production. The aim of this study was to investigate the biological pretreatment of synthetic and real produced water in a sequencing batch reactor (SBR) to remove hydrocarbon compounds. The SBR was inoculated with isolated tropical halophilic microorganisms capable of degrading crude oil. A total sequence of 24 h (60 min filling phase; 21 h aeration; 60 min settling and 60 min decant phase) was employed and studied. Synthetic produced water was treated with various organic loading rates (OLR) (0.9 kg COD m(-3) d(-1), 1.8 kg COD m(-3) d(-1) and 3.6 kg COD m(-3) d(-1)) and different total dissolved solids (TDS) concentration (35,000 mg L(-1), 100,000 mg L(-1), 150,000 mg L(-1), 200,000 mg L(-1) and 250,000 mg L(-1)). It was found that with an OLR of 0.9 kg COD m(-3) d(-1) and 1.8 kg COD m(-3) d(-1), average oil and grease (O&G) concentrations in the effluent were 7 mg L(-1) and 12 mg L(-1), respectively. At TDS concentration of 35,000 mg L(-1) and at an OLR of 1.8 kg COD m(-3)d(-1), COD and O&G removal efficiencies were more than 90%. However, with increase in salt content to 250,000 mg L(-1), COD and O&G removal efficiencies decreased to 74% and 63%, respectively. The results of biological treatment of real produced water showed that the removal rates of the main pollutants of wastewater, such as COD, TOC and O&G, were above 81%, 83%, and 85%, respectively.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Paper spray ionization (PSI) mass spectrometry (MS) is an emerging tool for ambient reaction monitoring via microdroplet reaction acceleration. PSI-MS was used to accelerate and monitor the time course of the reaction of dansyl chloride with aniline, in acetonitrile, to produce dansyl aniline. Three distinct PSI arrangements were explored in this study representing alternative approaches for sample loading and interaction; conventional single tip as well as two novel setups, a dual-tip and a co-axial arrangement were designed so as to limit any on-paper interaction between reagents. The effect on product abundance was investigated using these different paper configurations as it relates to the time course and distance of microdroplet travel. It was observed that product yield increases at a given distance and then decreases thereafter for all PSI configurations. The fluorescent property of the product (dansyl aniline) was used to visually inspect the reaction progress on the paper substrate during the spraying process. Amongst the variety of sample loading methods the novel dual-tip arrangement showed an increased product yield and microdroplet density, whilst avoiding any on-paper interaction between the reagents.
Signals consistent with the B_{c}^{+}(2S) and B_{c}^{*+}(2S) states are observed in proton-proton collisions at sqrt[s]=13 TeV, in an event sample corresponding to an integrated luminosity of 143 fb^{-1}, collected by the CMS experiment during the 2015-2018 LHC running periods. These excited b[over ¯]c states are observed in the B_{c}^{+}π^{+}π^{-} invariant mass spectrum, with the ground state B_{c}^{+} reconstructed through its decay to J/ψπ^{+}. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1±1.5(stat)±0.7(syst) MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the B_{c}^{+}(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(B_{c}^{+}) MeV, where the last term corresponds to the uncertainty in the world-average B_{c}^{+} mass.
This study aims to assess the chemical compositions of the essential oils from three Horsfieldia species namely H. fulva Warb., H. sucosa Warb. and H. superba Warb., which are found in Malaysia. The essential oils were derived from the samples through hydrodistillation which were then characterised by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Based on the findings, the H. fulva, H. sucosa and H. superba essential oils represented 98.2%, 98.7% and 98.5% of the total oils, respectively. The major component of H. fulva oil was identified to be germacrene D (20.8%), H. sucosa oil mainly contained α-cadinol (17.5%), whereas H. superba oil was rich in δ-cadinene (18.2%). To the best of our knowledge, this is the first study of the composition of the essential oils from these selected Horsfieldia species.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Penuaan ovari telah dikaitkan dengan tekanan oksidatif dan kehilangan fungsi ovari. Tokotrienol telah dibuktikan dapat memberi kesan yang baik terhadap sistem pembiakan wanita. Walau bagaimanapun, peranan tokotrienol ke atas metabolisma ovari dan seterusnya peningkatan kualiti oosit dalam mencit tua masih tidak diketahui. Oleh itu, hubungan antara perubahan aktiviti metabolik dalam ovari dan kualiti oosit dalam mencit tua selepas suplementasi fraksi kaya tokotrienol (TRF) telah dikaji. Mencit betina berusia enam minggu digunakan sebagai kumpulan Muda. Mencit betina berusia enam bulan dibahagikan kepada empat kumpulan iaitu kumpulan pertama yang diberikan minyak jagung-bebas tokoferol (kawalan) manakala tiga kumpulan yang lain diberi suplimen TRF pada dos 90, 120, dan 150 mg/kg. Rawatan diberikan secara oral selama dua bulan. Pada akhir rawatan, mencit dari semua kumpulan disuperovulasi dan kemudian dikorbankan. Kualiti oosit dinilai dan analisis metabolomik secara tidak disasarkan, pada tisu ovari dijalankan dengan menggunakan 'liquid chromatography tandem mass spectrometry of quadrupole time-of-flight' (LC-MS Q-TOF). Peratusan oosit normal adalah lebih tinggi (p
Long-tailed macaque (Macaca fascicularis) has the potential to be a good biological indicator for toxic exposure because they have an almost similar physiology and behaviour to humans. The objective of this study is to determine the concentration of lead (Pb) in hair samples of long-tailed macaques which were found in and out of the Kuala Selangor Nature Park (KSNP) area. The hypothesis is long-tailed macaques that live in the anthropogenic area (outside KSNP) may be exposed to high levels of lead compared to long-tailed macaques living in the forest area (inside KSNP). Analysis of hair samples were carried out using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The study found that the average mean of lead concentration in the anthropogenic area is 6.31 μg/g while for the forest area it is 3.16 μg/g. Lead concentration in the two areas are statistically insignificant. Nevertheless, lead concentration in the anthropogenic area recorded a slightly higher mean concentration than in the forest area. Even so, results of this study indicate that long-tailed macaques in Kuala Selangor are not exposed to high levels of lead. This study is the first in Malaysia to utilise long-tailed macaques as a biological indicator for testing the concentration of toxic substances in the environment. This study is still in its early stages; thus, future research requires improvements.
Pendedahan terhadap pestisid dapat menyebabkan penurunan paras unsur surih di dalam badan manusia. Unsur surih memainkan peranan penting dalam metabolisma tubuh. Kajian ini dijalankan untuk mengkaji paras unsur surih selenium, zink dan kromium dalam kalangan pesawah yang terdedah kepada pestisid di Wilayah I, MADA, Perlis. Kajian keratan rentas ini melibatkan 70 orang pesawah dan 57 orang yang tinggal di perkampungan nelayan sebagai kumpulan kawalan yang berumur di antara 21 hingga 80 tahun. Maklumat sosiodemografi pesawah dilakukan melalui temuduga borang soal selidik yang telah divalidasi. Pemeriksaan tekanan darah dan glukosa darah pesawah dilakukan. Paras selenium, zink dan kromium sampel kuku dan rambut dianalisis dengan menggunakan kaedah penghadaman asid dan mesin Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Hasil kajian mendapati bahawa paras selenium pada rambut (5.11 ± 17.05 μg/L) dan kuku (4.92 ± 2.17 μg/L) adalah lebih rendah secara signifikannya (p < 0.05) berbanding paras selenium pada rambut (15.67 ± 10.59 μg/L) dan kuku (6.67 ± 2.81 μg/L) kumpulan kawalan. Paras kromium pada rambut (31.83 ± 15.17 μg/L) dan kuku (87.64 ± 23.30 μg/L) kumpulan pesawah juga didapati lebih rendah secara signifikannya (p < 0.05) berbanding paras kromium pada rambut (85.19 ± 56.90 μg/L) dan kuku (99.36 ± 56.89 μg/L) pada kumpulan kawalan. Walau bagaimanapun, tiada perbezaan paras unsur surih yang signifikan (p > 0.05) menurut tempoh pendedahan pestisid. Kesimpulannya, paras selenium dan kromium pada kuku dan rambut pesawah yang terdedah kepada pestisid adalah lebih rendah berbanding kumpulan komuniti nelayan.
In recent years, environmental concerns over ultra-trace levels of steroid estrogens concentrations in water samples have increased because of their adverse effects on human and animal life. Special attention to the analytical techniques used to quantify steroid estrogens in water samples is therefore increasingly important. The objective of this review was to present an overview of both instrumental and non-instrumental analytical techniques available for the determination of steroid estrogens in water samples, evidencing their respective potential advantages and limitations using the Need, Approach, Benefit, and Competition (NABC) approach. The analytical techniques highlighted in this review were instrumental and non-instrumental analytical techniques namely gas chromatography mass spectrometry (GC-MS), liquid chromatography mass spectrometry (LC-MS), enzyme-linked immuno sorbent assay (ELISA), radio immuno assay (RIA), yeast estrogen screen (YES) assay, and human breast cancer cell line proliferation (E-screen) assay. The complexity of water samples and their low estrogenic concentrations necessitates the use of highly sensitive instrumental analytical techniques (GC-MS and LC-MS) and non-instrumental analytical techniques (ELISA, RIA, YES assay and E-screen assay) to quantify steroid estrogens. Both instrumental and non-instrumental analytical techniques have their own advantages and limitations. However, the non-instrumental ELISA analytical techniques, thanks to its lower detection limit and simplicity, its rapidity and cost-effectiveness, currently appears to be the most reliable for determining steroid estrogens in water samples.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*; Mass Spectrometry/methods
Prostate-specific antigen is currently the only protein biomarker routinely used as a diagnostic tool for early detection and treatment monitoring of prostate cancer. However, it remains questionable whether prostate-specific antigen-based screening can sensitively and selectively identify the presence and progression status of primary and metastatic prostate cancers. Hence, the purpose of this study was to identify potential biomarker candidates in the secretome of primary and metastatic prostate cancer cells by using a combination of global and targeted proteomics. Quantitative comparisons among secretome proteins derived from androgen-responsive primary cancer cells (P-22Rv1), androgen-irresponsive bone metastatic cancer cells (M-PC-3), and noncancerous prostate cells (N-PNT2) were performed using 2-dimensional image-converted analysis of liquid chromatography and mass spectrometry followed by in silico selection selected reaction monitoring analysis. Mediator of RNA polymerase II transcription subunit 13-like, insulin-like growth factor-binding protein 2, and hepatocyte growth factor were identified as highly secreted proteins from P-22Rv1 cells compared with N-PNT2 cells. Prostate-associated microseminoprotein, proactivator polypeptide, collagen-α-1 (VI) chain, and neuropilin-1 were identified as predominantly secreted proteins in M-PC-3 cells compared with N-PNT2 cells. These proteins in biological fluids are considered to be candidate biomarkers of primary and/or metastatic prostate cancer.
Matched MeSH terms: Mass Spectrometry/methods; Tandem Mass Spectrometry/methods*
Citrus peel essential oils have an impressive range of food and medicinal uses. In the present study we investigated the variation in the yield and chemical composition of the essential oils isolated from fresh, ambient-, and oven-dried peels of three Citrus species namely Citrus reticulata (C. reticulata), Citrus sinensis (C. sinensis) and Citrus paradisii (C. paradisii). The hydro-distilled essential oil content from fresh-, ambient-, and oven-dried peels of C. reticulata, C. sinensis and C. paradisii ranged from 0.30-0.50, 0.24-1.07 and 0.20-0.40 g/100 g, respectively. The maximum amount of the oil was determined in oven-dried while the minimum in fresh peel samples. Using GC and GC/MS, a total of 16-27, 17-24 and 18-40 chemical constituents were identified in the peel essential oils of C. reticulate, C. sinensis and C. paradisii, respectively. The content of limonene, the most prevalent chemical constituent, detected in these essential oils, ranged from 64.1-71.1% (C. reticulata), 66.8-80.9% (C. sinensis) and 50.8-65.5% (C. paradisii). The yield and content of most of the chemical components including limonene (the principal chemical compound detected) of the tested essential oils varied significantly (p < 0.05) with respect to drying treatments and species employed.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Kromium merupakan mineral yang penting dan kofaktor insulin yang memainkan peranan penting sebagai hormon yang membantu dalam regulasi gula dalam darah. Penduduk Kelantan sering dikaitkan dengan pengambilan makanan berasaskan gula. Petani merupakan golongan yang berisiko tinggi kerana pendedahan terhadap pestisid dan pengambilan makanan bergula boleh mempengaruhi paras kromium. Objektif kajian ini adalah untuk mengetahui status paras kromium dalam kalangan petani yang terdedah kepada pestisid dan baja kimia di Kelantan. Kajian ini adalah kajian keratan rentas yang dilakukan di Bachok dan Pasir Puteh, Kelantan. Responden adalah seramai 113 petani yang terdedah kepada pestisid atau baja kimia tidak kurang daripada satu tahun. Subjek ditemu bual menggunakan soal selidik pengetahuan, sikap dan amalan (KAP) yang telah divalidasi untuk informasi berkaitan data demografi k. Sampel kuku dan rambut telah dianalisia dengan menggunakan kaedah pencernaan asid dan Inductively Coupled Plasma Mass Spectroscopy (ICPMS) untuk mendapatkan paras kromium. Hasil kajian menunjukkan 81.4% adalah petani lelaki dan 18.6% adalah perempuan. Paras kromium kuku (125.82 ± 47.81 μg/L) dan rambut (39.63 ± 5.70 μg/L) petani adalah lebih rendah berbanding julat piawai kuku (6200 μg/L) dan rambut (100-2500 μg/L). Tiada perbezaan paras kromium yang signifi kan (p > 0.05) menurut jantina, umur, glukosa darah, tempoh pendedahan pestisid dan pemakanan. Petani yang merokok menunjukkan paras kromium yang lebih rendah (p < 0.05) berbanding petani yang tidak merokok. Kesimpulannya, paras unsur kromium petani di Bachok dan Pasir Puteh adalah rendah berbanding julat normal dan petani harus berhenti merokok kerana merokok akan merendahkan paras kromium.
Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) has been recognised as an effective technique to analyse car paint. This study was conducted to assess the combination of Py-GC-MS and chemometric techniques to classify car paint primer, the inner layer of car paint system. Fifty car paint primer samples from various manufacturers were analysed using Py-GC-MS, and data set of identified pyrolysis products was subjected to principal component analysis (PCA) and discriminant analysis (DA). The PCA rendered 16 principal components with 86.33% of the total variance. The DA was useful to classify the car paint primer samples according to their types (1k and 2k primer) with 100% correct classification in the test set for all three modes (standard, stepwise forward and stepwise backward). Three compounds, indolizine, 1,3-benzenedicarbonitrile and p-terphenyl, were the most significant compounds in discriminating the car paint primer samples.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Entamoeba histolytica membrane proteins are important players toward the pathogenesis of amoebiasis, but the roles of most of the proteins are not fully understood. Since efficient protein extraction method is crucial for a successful MS analysis, three extractions methods are evaluated for the use in studying the membrane proteome of E. histolytica: Two commercial kits (ProteoExtract from Calbiochem and ProteoPrep from Sigma), and a conventional laboratory method. The results show that ProteoExtract and the conventional method gave higher protein yields compared to ProteoPrep. LC-ESI-MS/MS identifies 456, 482, and 551 membrane fraction proteins extracted using ProteoExtract, ProteoPrep, and a conventional method, respectively. In silico analysis predicts 108 (21%), 235 (45%), and 177 (34%) membrane proteins from the extracts of ProteoExtract, ProteoPrep, and the conventional method, respectively. Furthermore, analysis of the cytosolic and membrane fractions shows the highest selectivity of the membrane proteins using the ProteoPrep extraction kit. Overall, this study reports 828 E. histolytica membrane fraction proteins that include 249 predicted membrane proteins. The data are available via ProteomeXchange with identifier PXD010171.
This study explores the role of sterols as lipid biomarkers to indicate their input which originates from various sources in the marine environment. Sterols and their ratios were investigated in sediments taken from sixteen sampling stations at Pulau Tinggi, Johor in order to assess the sources of organic matter. The compounds extracted from the sediments were quantified using a gas chromatography-mass spectrometry (GC-MS). The distributions of sterols indicated that organic matter at all sampling stations originated from a mixture of marine source and terrestrial origins at different proportions. A total of eleven sterols were quantified, with the major compounds being phytosterols (44% of total sterols), cholesterol (11%), brassicasterol (11%) and fecal sterols (12%).
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Catalytic co-pyrolysis (CCP) of spent coffee ground (SCG) and cellulose over HZSM-5 and HY was characterized thermogravimetrically, and a catalytic pyrolysis of two samples was conducted using a tandem micro reactor that directly connected with gas chromatography-mass spectrometry. To access the more fundamental investigations on CCP, the effects of the zeolite pore structure, reaction temperature, in-situ/ex-situ reaction mode, catalyst to feedstock ratio, and the SCG and cellulose mixing ratio were experimentally evaluated. The temperature showing the highest thermal degradation rate of cellulose with SCG slightly delayed due to the interactions during the thermolysis of two samples. HZSM-5 in reference to HY produced more aromatic hydrocarbons from CCP. With respect to the reaction temperature, the formation of aromatic hydrocarbons increased with the pyrolytic temperature. Moreover, the in-situ/ex-situ reaction mode, catalyst/feedstock, and cellulose/SCG ratio were optimized to improve the aromatic hydrocarbon yield.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
In mass spectrometry (MS)-based metabolomics, missing values (NAs) may be due to different causes, including sample heterogeneity, ion suppression, spectral overlap, inappropriate data processing, and instrumental errors. Although a number of methodologies have been applied to handle NAs, NA imputation remains a challenging problem. Here, we propose a non-negative matrix factorization (NMF)-based method for NA imputation in MS-based metabolomics data, which makes use of both global and local information of the data. The proposed method was compared with three commonly used methods: k-nearest neighbors (kNN), random forest (RF), and outlier-robust (ORI) missing values imputation. These methods were evaluated from the perspectives of accuracy of imputation, retrieval of data structures, and rank of imputation superiority. The experimental results showed that the NMF-based method is well-adapted to various cases of data missingness and the presence of outliers in MS-based metabolic profiles. It outperformed kNN and ORI and showed results comparable with the RF method. Furthermore, the NMF method is more robust and less susceptible to outliers as compared with the RF method. The proposed NMF-based scheme may serve as an alternative NA imputation method which may facilitate biological interpretations of metabolomics data.
Tocotrienol-rich fraction (TRF), a palm oil-derived vitamin E fraction, is reported to possess potent neuroprotective effects. However, the modulation of proteomes in differentiated human neuroblastoma SH-SY5Y cells (diff-neural cells) by TRF has not yet been reported. This study aims to investigate the proteomic changes implicated by TRF in human neural cells using a label-free liquid-chromatography-double mass spectrometry (LC-MS/MS) approach. Levodopa, a drug used in the treatment of Parkinson's disease (PD), was used as a drug control. The human SH-SY5Y neuroblastoma cells were differentiated for six days and treated with TRF or levodopa for 24 h prior to quantitative proteomic analysis. A total of 81 and 57 proteins were differentially expressed in diff-neural cells following treatment with TRF or levodopa, respectively. Among these proteins, 32 similar proteins were detected in both TRF and levodopa-treated neural cells, with 30 of these proteins showing similar expression pattern. The pathway enrichment analysis revealed that most of the proteins regulated by TRF and levodopa are key players in the ubiquitin-proteasome, calcium signalling, protein processing in the endoplasmic reticulum, mitochondrial pathway and axonal transport system. In conclusion, TRF is an essential functional food that affects differential protein expression in human neuronal cells at the cellular and molecular levels.
Hybridisation plays a significant role in the evolution and diversification of plants. Hybridisation among Nepenthes species is extensive, either naturally or man-made. To investigate the effects of hybridisation on the chemical compositions, we carried out metabolomics study on pitcher tissue of Nepenthes ampullaria, Nepenthes rafflesiana and their hybrid, Nepenthes × hookeriana. Pitcher samples were harvested and extracted in methanol:chloroform:water via sonication-assisted extraction before analysed using LC-TOF-MS. MS data were analysed using XCMS online version 2.2.5. This is the first MS data report towards the profiling, identification and comprehensive comparison of metabolites present in Nepenthes species.
A method using solid phase extraction and liquid chromatography-tandem mass spectrometry to quantitatively detect mitragynine, 16-carboxy mitragynine, and 9-O-demethyl mitragynine in human urine samples was developed and validated. The relevant metabolites were identified using multiple reaction monitoring in positive ionization mode using nalorphine as an internal standard. The method was validated for accuracy, precision, recovery, linearity, and lower limit of quantitation. The intra- and inter-day accuracy and precision were found in the range of 83.6-117.5% with coefficient of variation less than 13%. The percentage of recovery for mitragynine, 16-carboxy mitragynine, and 9-O-demethyl mitragynine was within the range of 80.1-118.9%. The lower limit of quantification was 1 ng/mL for mitragynine, 2 ng/mL for 16-carboxy mitragynine, and 50 ng/mL for 9-O-demethyl mitragynine. The developed method was reproducible, high precision and accuracy with good linearity and recovery for mitragynine, 16-carboxy mitragynine, and 9-O-demethyl mitragynine in human urine.