Gas Chromatography With Flame Ionization Detection Research Articles

Characteristics of volatile organic compounds (VOCs) at an urban site of Delhi, India: Diurnal and seasonal variation, sources apportionment

This study reports the measurements of 25 volatile organic carbon compounds (VOCs) in the ambient air at an urban location of Delhi, India. The air samples were collected in stainless steel canisters following the standard recommended practice of Environmental Protection Agency (EPA) and analysing using a gas chromatograph with Flame Ionization Detector (GC-FID) from January 2018 to June 2019. The most abundant are alkene (39%) followed by Alkane (36%), and aromatic (16%). Alkyne (9%) is observed in a very limited number of samples. Alkanes and aromatic compounds show a gradual decrease in concentration from morning to evening, whereas, the concentration of alkenes increased from morning to day time. Higher mixing height (m) during the day (0800–1800 h) and emissions from several sources have controlled the diurnal variation. VOCs show a strong seasonal cycle for alkanes (24–47%), alkenes (31–46%), Alkynes (4–18%), and aromatic compounds (14–20%). PCA/APCS-MLR analysis has been resolved 6 factors with 18 VOCs which are mostly dominated by gasoline evaporation (27.1%) and biomass burning (26.7%) followed by LPG (16.7%), and vehicular emissions (16.4%). PMF analysis shows gasoline vehicular emission + gasoline emission+ organic solvent (39.9%) followed by biomass burning (20.7%), LPG (15.8%), diesel vehicular emission (13.4%), and painting (10.1%).

A green evaluation of ecstasy determination methods by using different greenness criteria

The determination of 3,4-methylenedioxymethamphetamine (MDMA) in seized samples, by employing five different analytical procedures, has been used to illustrate the differences in their greenness classification depending on the selected evaluation criteria. A set of seventeen MDMA seized samples were analysed by: a) liquid chromatography with diode array detection (LC-DAD), b) gas chromatography with flame ionization detection (GC-FID), c) ion mobility spectrometry (IMS), d) total attenuated reflectance mid-infrared spectroscopy (ATR-FTIR) and e) diffuse reflectance near infrared spectroscopy (DR-NIR). The studied analytical procedures provided statistically comparable MDMA concentration values. However, the greenness scores of analytical procedures using the three criteria of Green Analytical Eco-Scale, the Green Analytical Procedure Index (GAPI) and the Analytical GREEnness metric approach (AGREE) provided significant differences but in all cases ATR-FTIR and DR-NIR were the greenest methods followed by IMS, GC and LC. The aforementioned greenness aspects are discussed in this study.

Chemical Composition, in Vitro Antibacterial and Antifungal Activities of Different Parts Essential Oils of Neolitsea sericea var. aurata From Taiwan

This study examined the chemical composition and antimicrobial activities of essential oils isolated from the leaves, twigs, and fruits of Neolitsea sericea var. aurata from Taiwan. The major compounds responsible for antimicrobial activity were isolated and identified. The leaf, twig, and fruit essential oils were obtained through hydrodistillation in a Clevenger-type apparatus and were characterized through gas chromatography (GC) with flame ionization detection (GC/FID) and GC/mass spectrometry (GC/MS). The major compounds were ( E)-β-ocimene (49.3%) and sericenine (31.6%) in the leaf oil; ( E)-β-ocimene (73.7%), α-cadinol (6.8%), and α-muurolol (4.0%) in the twig oil; and ( E)-β-ocimene (84.7%) in the fruit oil. The twig oil exhibited the strongest antibacterial and antifungal activities. We isolated α-cadinol and α-muurolol, the main components of NTO4 fraction, and used them in antimicrobial tests; the two compounds exhibited excellent antimicrobial activities. The twig essential oil contains α-cadinol and α-muurolol and exhibited excellent antimicrobial activities against food-borne pathogens; thus, they are worthy of further research and development.

Enzymatic Co-Fermentation of Onion Waste for Bioethanol Production Using Saccharomyces cerevisiae and Pichia pastoris

This paper evaluates the feasibility of bioethanol production from onion waste by Saccharomyces cerevisiae and Pichia pastoris and their novel co-culture through fermentation. The process parameters were optimized for each strain and their combination to observe the synergistic effect of co-fermentation. A dinitro salicylic acid (DNS) test was conducted to study the reducing sugar content of samples at different time intervals. Fourier transform infrared (FTIR) spectroscopic analysis was used to compare results for functional groups of samples before and after fermentation, and gas chromatography with flame ionization detection (GC-FID) analysis was performed to measure the bioethanol concentration obtained at different combinations of pH (5, 5.5, 6), temperature (20 °C, 30 °C, 40 °C), and time (24–110 h). The maximum bioethanol concentration was achieved through a monoculture of Saccharomyces cerevisiae, i.e., 30.56 g/L. The ethanol productivity was determined based on the ethanol concentration and fermentation time ratio. The energy content was determined using the obtained ethanol value and the specific energy content of ethanol, i.e., 30 kJ/g. The productivity and energy of bioethanol obtained at this maximum concentration were 0.355 g/L h and 916.8 kJ/L, respectively, after 86 h of fermentation at 30 °C and pH 5. Pichia pastoris produced a maximum of 21.06 g/L bioethanol concentration with bioethanol productivity and energy of 0.264 g/L h and 631.8 kJ/L, respectively, after 72 h of fermentation at 30 °C and pH 5. The coculture fermentation resulted in 22.72 g/L of bioethanol concentration with bioethanol productivity and energy of 0.264 g/L h and 681.6 kJ/L, respectively, after 86 h of fermentation at 30 °C and pH 5. The results of reducing sugars also supported the same conclusion that monoculture fermentation using Saccharomyces cerevisiae was the most effective for bioethanol production compared to Pichia pastoris and co-culture fermentation.

Heat treatment effect on tocopherols, total phenolics and fatty acids in table olives (Olea europaea L.)

The olive fruits are rich source of oil, vitamins, minerals, organic acids and pigments. The fruits contain high level of bioactive compounds. The aim of this study was to examine the effect of heat treatment on tocopherols, total phenolics and antioxidant activity in green and black olives, as well as their fatty acid composition. The instrumental methods used in this experiment were high performance liquid chromatography (HPLC), gas chromatography with flame ionization detection (GC/FID) and spectrophotometric methods. The results revealed that the β+γ-tocopherols content after the heat treatment had the biggest reduction, which was 68.4% for green and 80.2% for black olives. Also, a significant loss of total phenolic content was observed after heat treatment in green and black olives by 18.6% and 18.4%, respectively, as well as antioxidant activity (decrease up to 28.1%). The most abundant fatty acids in green and black olives were oleic (C18:1), palmitic (C16:0) and linoleic acid (C18:2). The changes in fatty acids composition during the heat treatment occurred mostly at the level of polyunsaturated fatty acids, especially linolenic acid (C18:3) in black olives had the significant reduction (by 57.4%) in relation to the initial quantity.

Chemical Profile and in-silico Docking Studies on Bioactives from Essential Oil of Cymbopogan pendulus Targeting Penicillin Binding Proteins (PBPs) in Bacteria

Antibiotic resistance in bacteria is the major concern worldwide. PBP (Penicillin binding proteins) have been cited as an appropriate target for therapeutic drug design. In the present study molecular docking followed by wet lab validation was designed to estimate the effect of potent bioactive molecules from Cymbopogan pendulus essential oil against PBP5 protein. GC-FID (gas chromatography with flame-ionization detection) based composition profile, and in-silico docking study was conducted by using CB-dock 2 analysis followed by 2D and 3D interactions. GC-FID revealed Limonene, Neral, Geranial, Linalool, Myrcene as major and minor compounds in Cymbopogan pendulus essential oil. The docking score indicated effective binding of ligands to PBP5. Interactions results indicated that, PBP5/ligand complexes form hydrogen and hydrophobic interactions. Wet lab study validated the anti-bacterial potential of oil against gram-positive and gram-negative bacteria. Therefore, essential oil from Cymbopogan pendulus essential oil may represent potential herbal treatment to mitigate bacterial infections.

Epiglottis Cartilage, Costal Cartilage, and Intervertebral Disc Cartilage as Alternative Materials in the Postmortem Diagnosis of Methanol Poisoning.

Alternative materials for postmortem diagnosis in the case of fatal poisonings are much needed when standard materials, such as blood and urine, are unavailable. The study presents a case of fatal mass methanol intoxication resulting from industrial alcohol consumption. The study aimed to determine methanol and formic acid concentrations in epiglottis cartilage, costal cartilage, and intervertebral disc cartilage and to analyze the correlation between their concentrations in cartilage tissues and the femoral blood. Methanol and formic acid concentrations in samples collected from 17 individuals (n = 17) were estimated using gas chromatography with flame ionization detection (GC-FID). Methanol concentration in the costal cartilage correlated with its concentration in the femoral blood (r = 0.871). Similar correlations were found for epiglottis cartilage (r = 0.822) and intervertebral disc cartilage (r = 0.892). Formic acid concentration in the blood correlated only with its concentration in urine (r = 0.784) and the epiglottis (r = 0.538). Cartilage tissue could serve as an alternative material for methanol analyses in postmortem studies. Formic acid, a methanol metabolite, does not meet the requirements for its presence determination in cartilage tissues.

Application of post-column reaction gas chromatography with a single reference gas for offshore air and gas seeped from the seafloor samples.

Ambient air commonly contains carbon dioxide at concentrations greater than 400µmolmol-1 and methane at ~ 2000nmolmol-1; non-methane hydrocarbons are also widespread in the atmosphere at much lower concentrations. For quantification of various carbon-containing compounds in typical analytical instrument, corresponding number of reference materials are required. Therefore, the development of a method that uses a single reference material applicable to air monitoring is desired. Here, we examined a post-column reaction system combined with a gas chromatograph equipped with a flame ionization detector (FID), which involves oxidation and reduction processes after separation. To determine various carbon-containing gases by post-column reaction gas chromatography with FID (GC-r-FID) using a single reference, it is necessary to confirm a good linearity of the response with carbon concentrations originating from various carbon-containing gases. When mixtures of carbon-containing gases at three different concentrations and the calibration curve of the FID response with the concentration converted into methane were used, a single linear calibration curve (correlation coefficient > 0.9999, 18 points) was obtained over four orders of magnitudes (to ~ 5000µmolmol-1 as methane). The applicability of GC-r-FID was confirmed by determining carbon-containing gases in air and gas seeped from the seafloor samples. Because the results were comparable to those obtained by conventional GC-FID and GC-thermal conductivity detector, typically GC-r-FID with a single reference gas should be suitable for air monitoring.

Hybrid volatilomics in cancer diagnosis by HS-GC-FID fingerprinting

Assessing volatile organic compounds (VOCs) as cancer signatures is one of the most promising techniques toward developing non-invasive, simple, and affordable diagnosis. Here, we have evaluated the feasibility of employing static headspace extraction (HS) followed by gas chromatography with flame ionization detector (GC-FID) as a screening tool to discriminate between cancer patients (head and neck—HNC, n = 15; and gastrointestinal cancer—GIC, n = 19) and healthy controls (n = 37) on the basis of a non-target (fingerprinting) analysis of oral fluid and urine. We evaluated the discrimination considering a single bodily fluid and adopting the hybrid approach, in which the oral fluid and urinary VOCs profiles were combined through data fusion. We used supervised orthogonal partial least squares discriminant analysis for classification, and we assessed the prediction power of the models by analyzing the values of goodness of prediction (Q2Y), area under the curve (AUC), sensitivity, and specificity. The individual models HNC urine, HNC oral fluid, and GIC oral fluid successfully discriminated between healthy controls and positive samples (Q2Y = 0.560, 0.525, and 0.559; AUC = 0.814, 0.850, and 0.926; sensitivity = 84.8, 70.2, and 78.6%; and specificity = 82.3; 81.5; 87.5%, respectively), whereas GIC urine was not adequate (Q2Y = 0.292, AUC = 0.694, sensitivity = 66.1%, and specificity = 77.0%). Compared to the respective individual models, Q2Y for the hybrid models increased (0.623 for hybrid HNC and 0.562 for hybrid GIC). However, sensitivity was higher for HNC urine and GIC oral fluid than for hybrid HNC (75.6%) and hybrid GIC (69.8%), respectively. These results suggested that HS-GC-FID fingerprinting is suitable and holds great potential for cancer screening. Additionally, the hybrid approach tends to increase the predictive power if the individual models present suitable quality parameter values. Otherwise, it is more advantageous to use a single body fluid for analysis.

The Preparation of Covalent Bonding COF-TpBD Coating in Arrayed Nanopores of Stainless Steel Fiber for Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons in Water.

Covalent organic framework (COF)-TpBD was grafted on the arrayed nanopores of stainless steel fiber (SSF) with (3-aminopropyl) triethoxysilane as the cross-linking agent. The prepared SSF bonded with COF-TpBD showed high thermal and chemical stability and excellent repeatability. The prepared SSF bonded with COF-TpBD was also used for the solid-phase microextraction (SPME) of seven kinds of polycyclic aromatic hydrocarbons (PAHs) in actual water samples, followed by gas chromatography with flame ionization detection (GC-FID) determination, which exhibited low limits of detection (LODs), good relative standard deviation (RSD) and high recoveries.

Determination of Polycyclic Aromatic Hydrocarbons in Mate Tea Microencapsulated with Maltodextrin and Lasiodiplodan ((1→6) β–D-Glucan)

The occurrence of polycyclic aromatic hydrocarbons (PAH) in organic mate tea (Ilex paraguariensis) was investigated to evaluate whether the roasting and drying processes under milder temperatures would promote lower PAH levels in the product. Gas Chromatography with Flame Ionization Detector (GC-FID) was used to quantify PAH contents. Different concentrations of PAH were found in all samples of mate tea analyzed, such as acenaphthylene varied between 1.209 and 1.524 µg·g−1; acenaphthene varied between 2.504 and 4.375 µg·g−1; fluorene varied between 1.488 and 1.843 µg·g−1; chrysene ranged between 0.093 and 0.263 µg·g−1; benzo[a]pyrene varied between 0.988 and 3,398 µg·g−1; dibenzo(a,h) anthracene was identified in all the samples, but at concentrations below the limit of quantification. Naphthalene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[k]fluoranthene were identified in the sample used for the extraction of soluble solids that have been encapsulated. The PAH concentration in mate tea samples was above the recommended by European Union legislation for dried herbs and powders of food of plant origin for the preparation of beverages. New yerba mate processing strategies should be studied to minimize PAH contamination and promote healthier products, in addition to government policies for quality control and regulation specifying limit values for the PAHs.

Combining portable NIR spectroscopy and multivariate calibration for the determination of ethanol in fermented alcoholic beverages by a multi-product model

In this study, a multivariate calibration multi-product model was built by combining partial least square regression (PLS) and portable near infrared (NIR) spectroscopy for the determination of ethanol content in fermented alcoholic beverages. Reference values were obtained by gas chromatography with flame ionization detection (GC-FID). Aiming at building a robust model, a great variety of beers, ciders, meads, and wines were incorporated into the model. NIR spectra were recorded between 908 and 1676 nm for 153 alcoholic beverage samples, corresponding to a range from 4.3 to 15.3% (v/v) of alcohol content. PLS model provided accurate results with root mean square errors of calibration (RMSEC) and prediction (RMSEP) of 0.8% and 0.9%, respectively. The developed method was validated through the estimate of proper figures of merit, such as linearity, trueness, precision, analytical sensitivity, bias, and residual prediction deviation (RPD). This method was simple, direct, rapid, of low-cost and environmentally friendly, not consuming reagents or solvents nor generating chemical waste. It could be incorporated in analytical platforms for quality inspection, contributing to provide better transparency in the food supply chain.

First report on quality and purity assessment of sweet almond oil in Brazilian body oils by gas chromatography and mass spectrometry.

Sweet almond oil is a raw material with high-added value used in different products. Then, the aim of this study is to evaluate the quality and purity of 10 body oils based on sweet almond oils currently available in the Brazilian market. Fatty acid composition and triacylglycerol (TAG) profile were determined by gas chromatography with flame ionization detector (GC-FID) and atmospheric solids analysis probe mass spectrometry (ASAP-MS), respectively. The authenticity of samples was assessed using an analytical curve equation. Soybean oil was chosen as the adulterant because it is the cheapest vegetable oil commercialized in Brazil. Hierarchical clustering analysis (HCA) in conjunction with ASAP-MS classified product samples according to the type of vegetable oil (soybean and sweet almond oils). The addition of soybean oil (8.79% to 99.70%) was confirmed in samples. However, only two samples stated in their label the presence of soybean oil as an ingredient. These findings highlight the need for better oversight by regulatory bodies to ensure that consumers acquire high quality and authentic products based on equally high quality and purity of sweet almond oils.

Volatile Compound Abundance Correlations Provide a New Insight into Odor Balances in Sauce-Aroma Baijiu

Sauce-aroma Baijiu (SAB) is one of the most famous Baijius in China; SAB has more than 500 aroma compounds in it. However, the key aroma compound in SAB flavor remains unclear. Volatiles play an important role in SAB aroma and are highly correlated to SAB quality. In the present study, 63 volatile compounds were quantified among 66 SAB samples using gas chromatography with flame ionization detector (GC-FID). The authors analyzed odor contributions and volatile compound correlations in two quality groups of SAB samples. Moreover, an odor activity value (OAV) ratio-based random forest classifier was used to explain the volatile compound relationship differentiations between the two quality groups. Our results proved higher quality SABs had richer aromas and indicated a set of fruity-like ethyl valerate, green- and malt-like isobutyraldehyde and malt-like 3-methylbutyraldehyde and sweet-like furfural, had closer co-abundance correlations in higher quality SABs. These results indicated that the aroma and contributions of volatile compounds in SABs should be analyzed not only with compound odor activity values, but also the correlations between different aroma compounds.

Exploring the Chemical Composition of Bulgarian Lavender Absolute (Lavandula Angustifolia Mill.) by GC/MS and GC-FID.

Lavender (L. angustifolia Mill.) is an important essential oil-bearing and medicinal plant with high commercial value. Lavender scent components can be derived not only as an essential oil but also as lavender concrete or absolute. The development of reliable analytical methods for origin assessment and quality assurance is of significant fundamental importance and high practical interest. Therefore, a comprehensive chemical profiling of seven industrial samples of Bulgarian lavender absolute (L. angustifolia Mill.) was performed by means of gas chromatography-mass spectrometry (GC/MS) and gas chromatography with flame ionization detection (GC-FID). As a result, 111 individual compounds were identified by GC/MS, and their quantitative content was simultaneously determined by GC-FID, representing 94.28-97.43% of the total contents of the lavender absolute. According to our results, the main constituents of lavender absolute (LA) are representatives of the terpene compounds (with the dominating presence of oxygenated monoterpenes, 52.83-80.55%), followed by sesquiterpenes (7.80-15.21%) and triterpenoids (as minor components). Coumarins in various amounts (1.79-14.73%) and aliphatic compounds (hydrocarbons, ketones, esters, etc.) are found, as well. The acyclic monoterpene linalool is the main terpene alcohol and, together with its ester linalyl acetate, are the two main constituents in the LAs. Linalool was found in concentrations of 27.33-38.24% in the LA1-LA6 samples and 20.74% in the LA7 samples. The amount of linalyl acetate was in the range of 26.58 to 37.39% in the LA1-LA6 samples, while, surprisingly, it was not observed in LA7. This study shows that the chemical profile of the studied LAs is close to the lavender essential oil (LO), fulfilling most of the requirements of the International Standard ISO 3515:2002.

In Situ Multi-Modal Approach for Electrode-Electrolyte Interfacial Chemistryand Electrode and Electrolyte Aging Behavior Studies

Increasing demands for cost-effective electric vehicles and electrochemical energy storage systems require advanced secondary batteries with higher energy density, longer lifetime, and enhanced safety. Increase of the battery operating voltage is one realistic strategy to extend the energy density, but it is accompanied by irreversible structural changes to the electrodes and parasitic reactions within an electrode-electrolyte interphase resulting in capacity fading and subsequent battery failure. Therefore, a fundamental understanding of underlying electrochemical mechanisms in the electrodes during battery cycling is critical for the development of next-generation secondary batteries.Based on our previous studies utilizing in situ surface-enhanced Raman spectroscopy to monitor the evolution of the Si-electrolyte interphase1 and in situ ATR-FTIR to investigate the voltage dependent electrolyte solution structure changes at the interface, transition metal redox chemistry, and cathode/electrolyte interfacial layer evolution,2 recently we updated the in situATR-FTIR with a newly designed ‘full-cell’ that enables us to analyze the interfacial reactions and interactions on the surfaces of both electrodes that directly influence battery performance, lifetime, and safety. Specifically, we focus on transition metal complex formation and its effect on solid-electrolyte interphase (SEI) formation and evolution on the anode due to transition metal dissolution and crosstalk of Mn-rich cathodes at high voltages (≥4.4 V).In addition, using our multi-modal characterization—a combination of in situ gas chromatography with flame ionization detection (GC-FID) and in situ ATR-FTIR—(electro)chemical degradation of the electrolyte is correlated with gas evolution in the battery. For example, GC-FID measures increasing amounts of ethylene gas until the end the first charging cycle of a LiNiO2//Graphite cell with Gen2 electrolyte (LiPF6 in ethylene carbonate (EC):ethyl methyl carbonate (EMC), 3:7 wt.%). Concurrently, in situ ATR-FTIR shows decreasing concentration of EC solvent, as calculated from the FTIR intensity of EC vibrational absorption. Ethylene is a known by-product of ethylene carbonate electrochemical reduction and is produced during SEI formation.3 Quantifying multiphase reactions occurring during battery operation is critical to understanding and mitigating battery degradation pathways, and developing next-generation battery materials systems.

Monitoring hydrocarbon levels during bioremediation by enhanced bio-stimulants using GC-FID

The efficacy of bio-stimulants on the remediation of hydrocarbon polluted soil was assessed using Gas Chromatography with Flame Ionization Detector (GC-FID). The enhanced bio-stimulants were discarded melon pulps, discarded breadfruit pulps and poultry droppings. These were applied to the polluted soil in the ratio of 1:5; the blend was observed for sixty days. Inferring from the chromatographs, the carbon compounds present in the polluted and remediated soils ranged from C12 – C40 with varying concentrations; C12 to C19 were dominant, C9 to C11 were residual with negligible concentrations. The total petroleum hydrocarbon (TPH) of polluted soil was 42,229.73 mg/kg, and the remediated soils were: biodegraded melon pulp - 23,786.3 mg/kg, biodegraded breadfruit pulp - 15,322.82 mg/kg, and chicken droppings, - 7,314.29 mg/kg. The results indicated that TPH of the polluted soil was reduced by 43.67% in sample remediated with biodegraded melon pulp, 63.71% in sample remediated with biodegraded breadfruit pulp, and 82.67% in sample remediated with chicken droppings. Therefore, a decreasing order of the effectiveness of the bio-stimulants is thus: chicken droppings > biodegraded breadfruit pulp > biodegraded melon pulp. The higher remediation potential of poultry droppings is attributable to high nitrogenous content. The study showed that the aforementioned bio-stimulants are effective in remediation of petroleum polluted soil. GC-FID detected the hydrocarbon present and their concentrations in the polluted and remediated soils. GC-FID is preferred to other analytical techniques due to its precision in identification and quantification of hydrocarbon fractions.

DLLμE/GC-MS as a Powerful Analytical Approach to Establish the Volatilomic Composition of Different Whiskeys

The volatilomic fingerprint of nine different whiskeys was established using a rapid and sensitive analytical approach based on dispersive liquid–liquid microextraction (DLLμE) followed by gas chromatography mass spectrometry detection (GC-MS) and gas chromatography with flame ionization detection (GC-FID). The influence of the extractor solvent on the extraction efficiency of volatile compounds (VOCs) was evaluated by DLLμE/GC-MS. The highest amounts of VOCs were obtained using 5 mL of sample, dichloromethane as the extractor solvent, and acetone as the disperser solvent. The proposed method showed no matrix effect, good linearity (R2 ≥ 0.993) in the assessed concentration range, recovery (ranging from 70 to 99%, precision (RSD ≤ 15%) and sensitivity (low limits of detection and quantification). A total of 37 VOCs belonging to different biosynthetic pathways including alcohols, esters, acids, carbonyl compounds, furanic compounds and volatile phenols were identified and quantified using DLLμE/GC-MS and DLLμE/GC-FID, respectively. Alcohols (3-methylbutan-1-ol, propan-1-ol), esters (ethyl decanoate, ethyl octanoate, ethyl hexanoate), and acids (decanoic acid, octanoic acid, hexanoic acid) were the most abundant chemical families. The multivariate statistical analysis allowed for the discrimination of whiskeys based on their volatilomic fingerprint, namely octanoic acid, 2-furfural, ethyl octanoate, ethyl hexanoate, acetic acid, ethyl dodecanoate, butan-1-ol, and ethyl decanoate.

Removal of COD and Ammoniacal-Nitrogen from Industrial Wastewater using Adsorption with Plantain Husk Adsorbent

The rate of depletion of ground/surface water has increased due to the weakness in the existing laws, contamination of the ground water and excess usage of water that produce increased quantity of wastewater. In this study, wastewater from Dangote Fertilizer Limited (DFL) was treated using adsorption method of treatment with consideration of the factors (pH, temperature and contact time) that impedes the efficiency of the method. Plantain husk, which is an agricultural waste, was used as adsorbent in the adsorption process. Response Surface Methodology (RSM) was used to determine the experimental number of runs after which it gives the optimum conditions of those parameters considered. The plantain husk was characterized using Gas chromatograph with Flame Ionization detector (GC-FID). The results obtained in the study revealed that utilization of the plantain husk as adsorbent in adsorption process for the removal of COD and Ammoniacal nitrogen from industrial wastewater will yield a high percentage removal (values). Ammoniacal nitrogen removal with plantain husk adsorbent was about 93% maximum and as pH increased to 7.5 (alkaline), a slight decrease in the Ammoniacal nitrogen removal percentage to about 92% could be attained. Furthermore, percentage removal of COD from the wastewater of about 83% maximum could be obtained. Effect of temperature on COD removal is a direct correlation as increase in temperature could lead to the decrease in COD removal. It can be concluded that the interaction between contact time and pH as compared to other interactions has an overall positive effect in the adsorption process of Ammoniacal nitrogen removal from wastewater. Being an agricultural waste and environmentally friendly materials, adsorbent from plantain husk should be considered for treatment of industrial waste water for removal of COD and ammoniacal nitrogen.

An evaluation of qH NMR: A complementary approach to GC-FID for quantification of Thymol and trans-Anethole in essential oils and supplements

Sweet fennel (Foeniculum vulgare Mill. var. dulce) and thyme (Zataria multiflora Boiss.) are regarded as the important supplies for pharmaceutical, food, cosmetic, and perfume industries. The major components trans-anethole and thymol are represented in fennel and thyme, respectively. The essential oils (EOs) content and the value of their related constituents should be given in strict quality control due to the storage conditions, source, and adulterations. In this study, we compared the validation of quantitative 1H NMR (qH NMR) method with the gas chromatography with flame ionization detection (GC-FID) to quantify the trans-anethole and thymol in fennel and thyme EOs and their related supplements. The current results showed that the quantification of trans-anethole and thymol by qH NMR method was successfully achieved from their EOs and supplements. All the validation parameters including linearity, robustness, repeatability, and stability were authenticated for thymol and trans-anethole quantification. Similar results were obtained in both qH NMR and conventional GC-FID methods. Therefore, according to the measured values, the qH NMR method was adequate to determine the constituents of the EOs, with the results being roughly comparable to those obtained by GC-FID, with the advantage of being simple, repeatable, rapid (8–10 min, while for GC-FID 55 min) and essential for quality control of commercial samples.