Headspace Gas Chromatography-mass Spectrometry Research Articles

Assessment of the di- and tri-chlorinated haloacetic acids during broiler prechilling.

Sodium hypochlorite (NaClO) has been widely used at 100ppm concentration during poultry slaughter to reduce carcass microorganism loads. However, its use in poultry processing is restricted owing to the potential risks of disinfection by-products (DBPs) that can be produced by the reaction of NaClO with poultry meat components. This study assessed whether dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), as primary DBP representatives, were produced when NaClO was used as a disinfectant in various methods during broiler prechilling. Headspace gas chromatography-mass spectrometry for the quantitative determination of DCAA and TCAA in 180 prechilling water samples and 30 broiler meat samples, obtained from large standard slaughterhouses equipped with an online monitoring system to control the NaClO concentration between 50 and 100ppm, showed that neither DCAA nor TCAA were detected. In simulation assays, haloacetic acids (HAAs) were not detected when the concentration of the NaClO solution was less than 200ppm with low frequency addition; however, more than 0.1mg/L of DCAA and TCAA were detected on applying 200, 300, 400, 500, and 1000ppm NaClO at high frequency. These findings indicated that adding high concentrations of NaClO and frequently adding low levels pose a potential risk of DBP formation. This investigation provides a basis for the establishment of food risk and the scientific use of NaClO in poultry processing, and contributes to the evaluation of DBPs in poultry slaughter. PRACTICAL APPLICATION: This study confirmed the occurrences of DCAA and TCAA during broiler chilling processing, indicating that formation of HAAs in simulation systems was correlated with NaClO levels and validated the absence of DCAA and TCAA with less than 200ppm,providing a basic study for food safety standards and regulations on the disinfectants used in food processing.

High-speed identification of odor changes and substance basis of Myristicae Semen mildew by electronic nose and HS-GC-MS

This study adopted headspace-gas chromatography-mass spectrometry(HS-GC-MS) and electronic nose to detect volatile components from Myristicae Semen samples with varying degrees of mildew, aiming at rapidly identifying odor changes and substance basis of Myristicae Semen mildew. The experimental data were analyzed by electronic nose and principal component analysis(PCA). The results showed that Myristicae Semen samples were divided into the following three categories by electronic nose and PCA: mildew-free samples, slightly mildewy samples, and mildewy samples. Myristicae Semen samples with different degrees of mildew greatly varied in volatile components. The volatile components in the samples were qualitatively and quantitatively detected by HS-GC-MS, and 59 compounds were obtained. There were significant differences in the composition and content in Myristicae Semen samples with different degrees of mildew. The PCA results were the same as those by electronic nose. Among them, 3-crene, D-limonene, and other terpenes were important indicators for the identification of mildew. Bicyclo[3.1.0]hexane, 4-methylene-1-(1-methylethyl)-, terpinen-4-ol, and other alcohols were key substances to distinguish the degree of mildew. In the later stage of mildew, Myristicae Semen produced a small amount of hydroxyl and aldehyde compounds such as acetaldehyde, 2-methyl-propionaldehyde, 2-methyl-butyraldehyde, and formic acid, which were deduced as the material basis of the mildew. The results are expected to provide a basis for the rapid identification of Myristicae Semen with different degrees of mildew, odor changes, and the substance basis of mildew.

Ethanol Concentration of Kombucha Teas in British Columbia, Canada

Kombucha is a sweetened tea beverage fermented by bacterial and yeast cultures. Sweeteners, such as glucose, sucrose, fructose, and others are converted by yeasts into ethanol and then by Acetobacter and other bacterial species into a weak acetic acid solution that is diluted, flavored, and packaged into glass or aluminum cans for consumer consumption. Naturally, fermented kombucha contains 0 to 3% alcohol by volume (ABV). However, kombucha containing ethanol is concerning for pregnant women and young children for whom low levels of ethanol consumption (<3% ABV) create adverse medical outcomes. In the province of British Columbia (BC), Canadian beverages containing >1% ABV are regulated as liquor. This study assessed ethanol concentrations in kombucha collected from processors and purchased at retail venues in BC. Ethanol values were compared with the place of manufacture (country or province) and place of purchase (grocery stores, restaurants, farmers' markets, recreational centers, and processors). Ethanol (n = 684) levels were measured by using a headspace gas chromatography-mass spectrometry method with a detection limit of 0.0002% ABV for ethanol. Overall, teas contained mean and median ethanol of 0.77 and 0.62% ABV, respectively, ranging from nondetectable up to 3.62% ABV. Four kombucha teas (0.6%) made by BC processors tested over 3% ABV, and 31.5% of samples contained ethanol that exceeded the BC regulatory limits for nonalcoholic beverages of 1% ABV. Kombucha manufactured in BC had significantly higher mean ethanol values (1.16% ABV) in comparison to all other places of manufacture. Similarly, mean ethanol tea values obtained from BC processors (1.2% ABV) and restaurants (1.01% ABV) were significantly higher than those obtained at other retail venues. This study demonstrates the potential for alcohol harm to at-risk populations consuming kombucha teas sold in BC.

Comparison of the Chemical and Sensorial Evaluation of Dark Chocolate Bars

As it mimics olfactory perception, headspace analysis is frequently used for examination of products like chocolate, in which aroma is a key feature. Chemical analysis by itself, however, only provides half the picture, as final consumer’s perception cannot be compared to that of a Gas Chromatography-Mass Spectrometry (GC-MS) port, but rather to a panel test assessment. The aim of the present study was the evaluation of combined chemical (by means of headspace solid-phase microextraction and GC-MS) and panel test data (by means of a sensory evaluation operated by 6 untrained panelists) obtained for 24 dark chocolate bars to assess whether these can discriminate between bars from different brands belonging to different commercial segments (hard discount, HD; supermarket, SM; organic bars, BIO). In all samples, with the only exception of one supermarket bar (in which esters exhibited the highest relative abundance), pyrazines were detected as the most abundant chemical class (HD: 56.3–74.2%; BIO: 52.0–76.4%; SM: 31.2–88.9%). Non-terpene alcohols, aldehydes, and esters followed as quantitatively relevant groups of compounds. The obtained data was then subjected to hierarchical cluster (HCA) and principal component (PCA) analysis. The statistical distribution of samples obtained for the chemical data did not match that obtained with panelists’ sensorial data. Moreover, although an overall ability of grouping samples of the same commercial origin was evidenced for hard discount and supermarket bars, no sharp grouping was possible.

To Investigate the Effect of Using Ethanol Containing Wipes in Collecting Blood for the Measurement of Alcohol Concentration

This study was aimed to establish whether the skin preparation using ethanol-containing skin antiseptics causes ethanol contamination through blood collection. Venous blood was collected from 40 healthy volunteers according to the national guidelines for blood sampling, with four sequential procedures as follows: 1) collecting blood immediately (within 5 seconds) after cleaning the skin with an individually packaged type of ethanol-containing wipe, 2) collecting blood 1 minute after cleaning the skin with an individually packaged type of ethanol-containing wipe, 3) collecting immediately (within 5 seconds) after cleaning the skin with a traditional cleaning method (thoroughly ethanol-impregnated wipe, and 4) collecting 1 minute after cleaning the skin with a traditional cleaning method. Each sequential procedure was performed with and without the ethanol-containing wipe used for skin cleaning on the puncture site on their right and left arms at the time the needle was withdrawn, respectively. The collected specimens were subjected to the determination of ethanol by using headspace gas chromatography-mass spectrometry. In every 80 blood specimens obtained from 40 participants, ethanol was undetectable (<0.001 mg/mL). This study demonstrates that disinfection using ethanol-containing skin antiseptics is unlikely to cause ethanol contamination through blood collection regardless of skin preparation technique according to the guidelines for blood sampling. This may have implications in forensic science.

Photochemical interactions between pesticides and plant volatiles

Among the numerous studies devoted to the photodegradation of pesticides, very scarce are those investigating the effect of plant volatiles. Yet, pesticides can be in contact with plant volatiles after having been spread on crops or when they are transported in surface water, making interactions between the two kinds of chemicals possible. The objectives of the present study were to investigate the reactions occurring on plants. We selected thyme as a plant because it is used in green roofs and two pesticides: the fungicide chlorothalonil for its very oxidant excited state and the insecticide imidacloprid for its ability to release the radical NO2 under irradiation. Pesticides were irradiated with simulated solar light first in a solvent ensuring a high solubility of pesticides and plant volatiles, and then directly on thyme's leaves. Analyses were conducted by headspace gas chromatography–mass spectrometry (HS-GC–MS), GC–MS and liquid chromatography-high resolution mass spectrometry (LC-HRMS). In acetonitrile, chlorothalonil photosensitized the degradation of thymol, α-pinene, 3-carene and linalool with high quantum yields ranging from 0.35 to 0.04, and was photoreduced, while thymol underwent oxidation, chlorination and dimerization. On thyme's leave, chlorothalonil was photoreduced again and products arising from oxidation and dimerization of thymol were detected. Imidacloprid photooxidized and photonitrated thymol in acetonitrile, converting it into chemicals of particular concern. Some of these chemicals were also found when imidacloprid was irradiated dispersed on thyme's leaves. These results show that photochemical reactions between pesticides and the plants secondary metabolites can take place in solution as on plants. These findings demonstrate the importance to increase our knowledge on these complex scenarios that concern all the environmental compartments.

Aging cats prefer warm food

The aim of this study was to determine if meal temperature of cat wet food affected the feeding preference of aging (>7 years of age) domestic short-haired cats. We examined a chunks in gravy product served at three nominal temperatures of 6⁰C, 21⁰C, and 37⁰C using a two-bowl difference test. Gravy viscosity was measured using a Brookfield DV1 viscometer and the percentage of volatile compounds released at each product temperature was also analysed using headspace solid-phase micro-extraction and gas chromatography-mass spectrometry. The aging cats significantly preferred the warmer products in all pairwise comparisons, 6⁰C < 21⁰C < 37⁰C, with the product at 37⁰C being the most preferred. The gravy viscosity was almost identical at each temperature, however, significant changes were observed in 11 out of the 15 volatile compound chemical classes measured at the different product temperatures. Hence, warming may increase the attractiveness by changing and/ or enhancing the flavor profile for aging cats. Understanding the feeding behaviors and preferences of aging cats is an important area of research. Warmed wet food can help to promote food consumption in aging cats, especially those that have lost interest in eating or do not consume enough product to maintain a healthy body weight.

Mass balance method for SI-traceable purity assignment of synthetic oxytocin

Oxytocin is not only a significant peptide drug for enhancing uterine contractions, but also an emerging biomarker and therapeutic target of mental disorders in clinical practice. There is a pressing need for the standardization of oxytocin assays because of its low pharmaceutical quality and large variations among measurement approaches. International System of Units (SI)-traceable analytical methods and well-characterized pure reference materials are urgently needed to set up standard reference measurement systems in laboratory medicine, ensuring the accuracy and comparability of test results. Herein, the purity assignment of a synthetic oxytocin containing a disulfide linkage was established based on a mass balance method, which had never been performed for a cross-linked peptide. An in-house validated liquid chromatography-high-resolution tandem mass spectrometry method was developed for the determination of structurally-related impurities in the study material. Twenty-one structurally-related impurities including deamidations, oxidations, and amino acid insertions, etc. ranging from 0.05 mg g-1 to 15.65 mg g-1 were identified and quantified by applying a hierarchy calibration concept. This study subsequently discusses a fit for purpose assessment for non-peptide related impurities including water, non-volatile counterions, inorganic elements, and volatile organic compounds that were determined using coulometric Karl Fischer titration, ion chromatography, inductively coupled plasma mass spectrometry, and headspace gas chromatography-mass spectrometry, respectively. The resulting assigned value (796.5 mg g-1) is determined to be traceable to SI associated with a small measurement uncertainty of 6.5 mg g-1 (k = 2). The method developed in this study has been verified through an international key comparison jointly coordinated by the Bureau International des Poids et Mesures and the National Institute of Metrology.

Characterization of volatile compounds and physicochemical properties of hongeo using headspace solid-phase microextraction and gas chromatography-mass spectrometry during fermentation

Changes in the volatile composition and some chemical properties of fermented skate, hongeo at different stages in its fermentation process were investigated using headspace solid-phase microextraction and gas chromatography-mass spectrometry. The result showed that a significant increase in pH, ammonia nitrogen, total volatile base nitrogen (TVBN) and trimethylamine nitrogen (TMAN) content during fermentation. A total of 208 volatile compounds, consisting mainly of hydrocarbons, alcohols, ketones, esters, amines, aldehydes, sulfur compounds, indoles, phenols, and other compounds, were detected and identified. Volatile compounds including amines, hydrocarbons, and alcohols were dominant in the unfermented hongeo samples, whereas pyrazines, indoles, phenols and sulfur compounds appeared from the early or middle stage and increased until the end of fermentation. The significant increase in abundance and relative content of volatile compounds at the initial fermented stage indicated that the metabolic activity of microorganisms plays an important role in the formation of the unique flavor. We present SPME/GC-MS as a useful tool for monitoring the volatile compounds of hongeo during fermentation, and provide important information for investigating the mechanism of unique flavor formation in hongeo products.

Lignin Resists High-Intensity Electron Beam Irradiation.

The electron beam irradiation (EBI) of native lignin has received little attention. Thus, its potential use in lignin-based biorefineries is not fully understood. EBI was applied to selected lignin samples and the structural and chemical changes were analyzed, revealing the suitability, limitations, and potential purpose of EBI in wood biorefineries. Isolated milled wood, kraft, and sulfite lignin from beech and eucalyptus were subjected to up to 200 kGy of irradiation. The analysis included gel permeation chromatography for molar masses, heteronuclear single quantum coherence (HSQC)- and 31P NMR and headspace gas chromatography-mass spectrometry for functional groups, and thermogravimetric analysis for thermal stability. Most samples resisted irradiation. Subtle changes occurred in the molecular weight distribution and thermal stability of milled wood lignin. EBI was found to be a suitable pretreatment method for woody biomass if the avoidance of lignin condensation and chemical modification is a high priority.

Sound Stimulation Can Affect Saccharomyces cerevisiae Growth and Production of Volatile Metabolites in Liquid Medium.

The biological effect of sound on microorganisms has been a field of interest for many years, with studies mostly focusing on ultrasonic and infrasonic vibrations. In the audible range (20 Hz to 20 kHz), sound has been shown to both increase colony formation and disrupt microbial growth, depending upon the organism and frequency of sound used. In the brewer’s yeast Saccharomyces cerevisiae, sound has been shown to significantly alter growth, increase alcohol production, and affect the metabolite profile. In this study, S. cerevisiae was exposed to a continuous 90 dB @ 20 μPa tone at different frequencies (0.1 kHz, 10 kHz, and silence). Fermentation characteristics were monitored over a 50-h fermentation in liquid malt extract, with a focus on growth rate and biomass yield. The profile of volatile metabolites at the subsequent stationary phase of the ferment was characterised by headspace gas chromatography–mass spectrometry. Sound treatments resulted in a 23% increase in growth rate compared to that of silence. Subsequent analysis showed significant differences in the volatilomes between all experimental conditions. Specifically, aroma compounds associated with citrus notes were upregulated with the application of sound. Furthermore, there was a pronounced difference in the metabolites produced in high- versus low-frequency sounds. This suggests industrial processes, such as beer brewing, could be modulated by the application of audible sound at specific frequencies during growth.

Determination of each single component vegetable oil in blend oil by headspace gas chromatography-mass spectrometry

A method of headspace gas chromatography-mass spectrometry was established for the determination of the content of each single component vegetable oil in blend oil based on soybean oil, peanut oil and sesame oil. The data of volatile components of each single component vegetable oil was collected effectively by headspace gas chromatography-mass spectrometry. The data was compared, filtered step by step and evaluated by method ology using chemometrics method and group analysis software. Finally, 2, 4-heptanedialdehyde, 2-decendialdehyde and 5-methyl-2-furfural were identified as the quantitative detection marker compounds of soybean oil, peanut oil and sesame oil, respectively. Dihydro-3-methylene-5-methyl-2-furanone and trans-2-nonenoldehyde, 4-ethyl-5-methyl-nonane and trans-2-dodecenol, 2-(1-pentenyl)-furan and 2-methylpyrazine were the qualitative compounds of soybean oil, peanut oil and sesame oil, respectively. The regression equations and linear correlation coefficient(r~2) of soybean oil, peanut oil and sesame oil were obtained by testing nine level simulated blend oil. The linear range were 0.57%-100%, 0.98%-100%, 0.34%-100%. The precision range were 1.4%-3.8%, 9.0%-16.0%, 5.0%-10.4%(n=6). The recovery range were 100.1%-100.5%, 75.0%-115.3%, 87.0%-100.6%. These data met the requirements of method ology. The method is applicable to testing research of the content of each single component vegetable oil in blend oil based on soybean oil, peanut oil and sesame oil.

Assessing urinary odours across the oestrous cycle in a mouse model using portable and benchtop gas chromatography-mass spectrometry.

For female mammals, communicating the timing of ovulation is essential for reproduction. Olfactory communication via volatile organic compounds (VOCs) can play a key role. We investigated urinary VOCs across the oestrous cycle using laboratory mice. We assessed the oestrous stage through daily vaginal cytology and analysed urinary VOCs using headspace gas chromatography-mass spectrometry (GC-MS), testing a portable GC-MS against a benchtop system. We detected 65 VOCs from 40 samples stored in VOC traps and analysed on a benchtop GC-MS, and 15 VOCs from 90 samples extracted by solid-phase microextraction (SPME) and analysed on a portable GC-MS. Only three compounds were found in common between the two techniques. Urine collected from the fertile stages of the oestrous cycle had increased quantities of a few notable VOCs compared with urine from non-fertile stages. These VOCs may be indicators of fertility. However, we did not find significant differences in chemical composition among oestrous stages. It is possible that changes in VOC abundance were too small to be detected by our analytical methods. Overall, the use of VOC traps combined with benchtop GC-MS was the more successful of the two methods, yet portable GC-MS systems may still have utility for some in situ applications.

Exploring urinary biomarkers to assess oxidative DNA damage resulting from BTEX exposure in street children

Children are highly susceptible to environmental contaminants as their physiology and some metabolic pathways differ from adults. The present cross-sectional study aimed to assess whether exposure to benzene, toluene, ethylbenzene, o,p-xylene, and m-xylene (BTEX) affects oxidative DNA damage in street children using a biomonitoring approach. Thirty-five boys (7–13 years of age), exposed by working at a busy intersection, and 25 unexposed boys of similar age and living in the neighborhood near the busy intersection were recruited. Urinary un-metabolized BTEX levels were quantified by a headspace gas chromatography-mass spectrometry (GC–MS). Urinary malonaldehyde (MDA) was measured with spectrophotometry. Sociodemographic and lifestyle conditions information was collected by interviews using administered questionnaires. Exposed subjects provided urine before (BE) and after work exposure (AE), while unexposed boys gave a single morning sample. Urinary BTEX concentrations in BE samples were similar to unexposed. Concentrations in AE samples were 2.36-fold higher than observed in BE samples (p < 0.05) and higher than those in the unexposed group (p < 0.05). In addition, urinary MDA levels in AE samples were 3.2 and 3.07-times higher than in BE samples and in the unexposed group (p < 0.05). Environmental tobacco smoke (ETS) increased urinary BTEX and MDA levels in both groups. Our findings confirm that street children working at busy intersections are significantly exposed to BTEX, which is associated with oxidative stress. Implementing protective measures is crucial to reduce exposure and to improve health outcomes in this group.

Efficient identification of raw and ripe tung oil using headspace GC-MS.

To differentiate between the raw type and ripe type of tung oil, it is important to distinguish between the types of tung oil before its application. In the present work, an efficient headspace gas chromatography-mass spectrometry (HS-GC-MS) method was developed for identifying eight samples T1-T8, including the raw tung oil and ripe tung oil. The HS-GC-MS experiments results showed that octanoic acid existed only in ripe tung oil of T2, T4, T6, T8, not in raw tung oil of T1, T3, T5, T7. Combined with structural characterization by tandem mass spectrometry, octanoic acid was screened as an effective marker for distinguishing between raw tung oil and ripe tung oil. Then, the HS-GC-MS method was applied into the putty samples of X1 (raw tung oil with lime) and X2 (ripe tung oil with lime) and successfully identified the samples X1 mixed with raw tung oil and X2 mixed with ripe tung oil. The further validations results suggested that the detection limit of our HS-GC-MS method could reach 1.05 mg/L for octanoic acid, whereas the detection limit of derivative gas chromatography-mass spectrometry (DR-GC-MS) method was 2.74 mg/L for methyl octanoate. The investigation results can also provide the useful information and technical support for the selection of restoration materials and technology in ancient buildings.

Rapid discrimination and screening of volatile markers for varietal recognition of Curcumae Radix using ATR-FTIR and HS-GC-MS combined with chemometrics

Ethnopharmacological relevanceCurcumae Radix (Yujin) has a long medicinal use history in China, which is used to cure diseases like jaundice, cholelithiasis caused by dampness-heat of gallbladder and liver, and so on. It comes from the dried tuberous roots of C. kwangsiensis (Guiyujin), C. longa (Huangyujin), C. phaeocaulis (Lvyujin) and C. wenyujin (Wenyujin). Though there are differences in chemical compositions and pharmacological activities among the four species of Yujin, they have not been differentiated well in clinical application due to their similar morphological characterizations. Aim of the studyIn this study, the four species of Yujin were rapidly and accurately discriminated. The potential volatile markers for varietal recognition were identified. Materials and methodsAttenuated total reflection fourier transformed infrared (ATR-FTIR) spectroscopy combined with chemometrics was used to rapidly discriminate the four species of Yujin. Headspace-gas chromatography-mass spectrometry (HS-GC-MS) technology coupled with chemometrics was employed to characterize volatile profiling, differentiate species and select potential markers for varietal recognition of Yujin. ResultsBy applying PCA (principal components analysis) and HCA (hierarchical cluster analysis), HS-GC-MS realized complete differentiation of the four species of Yujin, while ATR-FTIR only recognized Guiyuijin. Back propagation neural network (BP-NN), KNN (K-nearest neighbor) and LDA (linear discriminant analysis) models based on spectral data achieved 100% discriminant accuracies. Support vector machines (SVM), KNN and PLS-DA (partial least square discriminant analysis) models based on volatile compounds also realized 100% discriminant accuracies. Additionally, the potential volatile markers for varietal recognition of Yujin were screened using PLS-DA, including 2 for Guiyujin, 6 for Lvyujin, 9 for Wenyujin and 13 for Huangyujin. ConclusionsThe present study developed reliable methods for the varietal discrimination and volatile compounds characterization of Yujin, which will provide references for its quality control and clinical efficacy.

Endogenous formation of 1-propanol and methanol after consumption of alcoholic beverages

IntroductionIn cases of drunk-driving, allegations that alcohol has been consumed after the incident, are proved by analyzing congener alcohols in the blood sample. 1-Propanol, one of the main congener compounds, was tested, whether it is also endogenously formed when a person has consumed alcoholic beverages. MethodsEleven male and 13 female volunteers consumed congener-free vodka (37.5 vol% ethanol, individual doses: 0.15–0.32 l) within one hour. Blood samples were taken up to 10 h and analyzed for ethanol and congener alcohols by headspace gas chromatography-mass spectrometry. ResultsEthanol concentrations reached in blood a maximum of 0.65–1.23 g/l and decreased by 0.18 g/l/h (median values). Of the congener alcohols analyzed, only methanol and 1-propanol were detected in the plasma samples of all subjects. The endogenous methanol concentration increased from 0.66 mg/l by 0.22 mg/l/h to 2.19 mg/l (medians). 1-Propanol was not detected prior to alcohol consumption. Maximum concentrations of 0.10–0.32 mg/L were measured after 1.0–4.5 h. A plateau of the 1-propanol concentration was observed in the plasma samples of the 18 subjects lasting for 0.5–4.0 h and this alcohol was completely eliminated at ethanol concentrations of 0.17 g/l (median, range 0.03–0.55 g/l). ConclusionThe results of the study confirm the formation of 1-propanol after consumption of 1-propanol-free beverages, which should be taken into account when evaluating its concentration.

Headspace Gas Chromatography/Mass Spectrometry Analysis Endorses Melaleuca Species as Abundant Source of Medicinal Eucalyptol and Its Proposed Anti-Obesity Activity

In the present study, the essential oils of the five Melaleuca species, ( Melaleuca bracteata, Melaleuca styphelioides, Melaleuca nesophila, Melaleuca leucadendra, and Melaleuca ericifolia ) were analyzed via headspace gas chromatography/ mass spectrometry (HS-GC/MS) analysis the unveiled considerable differences among the five Melaleuca accessions. Twelve volatile constituents were identified in the essential oils of Melaleuca accessions. Oxygenated monoterpene exemplified by eucalyptol was the main constituent in M. leucadendra and M. nesophila oils representing 97.62% and 95.08% of their aroma correspondingly followed by M. styphelioides (56.10 %), M. ericifolia (29%), and lastly M. bracteata (10.71%). A consecutive molecular network was constructed via the GNPS (Global Natural Products Social Molecular Networking) for the visual exploration of the volatile constituents among Melaleuca species. The constructed molecular network divulged eucalyptol (1,8 cineole) as the prevailing volatile, especially in M. leucadendra oil. Quantitative estimation of eucalyptol content in the studied species proved M. leucadendra oil as a potential source for its isolation with a content of 6031.8 µg/g dry weight. In addition, the effect of eucalyptol on the activity of digestive enzymes (α-amylase and pancreatic lipase) was assessed. Eucalyptol showed IC50 values of 75.3±2.1 and 64.6± 1.4 µg/ml for α-amylase and pancreatic lipase inhibition, compared with acarbose and orlistat 34.71±1.3 and 23.8± 0.82 µg/ml, respectively with significant difference of p Further target prediction studies for eucalyptol were applied and proposed the Cytochrome 450 19A1 aromatase enzyme as a possible target of eucalyptol that could be a potential alternative therapy in the management of obesity.

Headspace gas chromatography-mass spectrometry in the analysis of lavender’s essential oil: Optimization by response surface methodology

A static headspace gas chromatography - mass spectrometry (HS–GC/MS) method was developed and optimized with the aim to be applied in the analysis of lavender essential oil. To obtain a comprehensive profile of the essential oil, the optimum HS–GC/MS method parameters were selected based on a Design of Experiments (DοE) process. Plackett-Burman experimental design was applied by utilizing seven parameters of the HS injection system. Incubation equilibration temperature and time, agitator’s vortex speed, post injection dwell time, inlet temperature, split ratio and injection flow rate were screened to select the optimum conditions on the basis of the number and the intensity of the identified compounds. Other parameters, such as sample volume and dilution solvent ratio, were also examined to achieve a comprehensive profile in a chromatographic run of 55 min. With the obtained optimum method, more than 40 volatile compounds were identified in lavender’s essential oils from different geographical regions in Greece. The method can be utilized for the quality assessment of lavender’s essential oil and provide information on its characteristic aroma and discrimination among species based on the acquired GC–MS profiles.

Determination of furan in canned foods and packaged beverages by headspace gas chromatography-mass spectrometry

A headspace gas chromatography-mass spectrometry(HS-GC-MS) method for the analysis of furan in canned foods and packaged beverages was established. The furan was extracted from the samples by headspace method. D_4-furan was used as internal standard and separated on a HP-Plot Q(30 m×0.32 mm, 20 μm) column. The results were qualitative and quantitative by gas chromatography-mass spectrometry. The linear range of this method was 2.0-200.0 ng, and the regression equation of the working curve was y=1.14x +0.116(r~2=0.999). The recoveries were 86.3%-96.2% with the relative standard deviations(RSDs) less than 10%(n=6). The limit of quantification of furan was 1.0 ng. Through the detection of 59 samples, it was found that the common canned food and hard packaged drinks were commonly contaminated with furan, and the concentration of furan in coffee, milk tea, canned fish and other products were relatively high, with a maximum value of 153.99 ng. The method is simple, rapid, accurate and reliable, and could be used for the detection of furan in the two kinds of food.