Gas Chromatography Coupled With Flame Ionization Detector Research Articles

Impact of Distillation Process on the Major Volatile Compounds as Determined by GC-FID Analysis in Apple Brandy Originated from Transylvania, Romania

There were analyzed samples of fruit distillates from the two stages of distillation process, first distillate and the second distillate, as apple brandy originating from BistriÅ£a-Năsăud County, Transylvania provenience and were collected directly from the producer soon after the process ended. We investigated 10 major volatile compounds (acetaldehyde, ethyl acetate, methanol, 1-propanol, 1butanol, 2-butanol, isobutylic alcohol, isoamylic alcohol, amyl active alcohol and furfural) by gas chromatography coupled with flame ionization detector (GC-FID). We used reference chemicals to identify these compounds and 3-pentanol as internal standard to quantify the volatiles. This analysis permitted to observe the differences between the two distillates. Acetaldehyde, ethyl acetate and methanol have smaller amounts in the second distillation step. Furfural and higher alcohols registered different evolution in the last distillation step. They were higher then in the first distillate. The factors which differentiate the two samples can be separation of fractions (heads, hearts and tails), temperature, quality of raw material and the fermentation process.Â

Acetylcholinesterase (AChE) inhibitory activity, antioxidant properties and phenolic composition of two Aframomum species

Aframomum species are widely used as a food supplement and remedy in folklore medicine for the management of several diseases. This study was designed to investigate the acetylcholinesterase inhibitory activity and antioxidant properties of phenolic-rich extracts from two Aframomum species: Aframomum danielli (Hook F.) K. Schum (Zingiberaceae) and Aframomum melegueta (Roscoe) K. Schum (Zingiberaceae) seeds. Acetylcholinesterase inhibitory activity and antioxidant properties [inhibition of quinolinic acid (QA)-induced lipid peroxidation in rat brain, reducing properties, 2,2-azinobis (3-ethylbenzo-thiazoline-6-sulfonate) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging abilities] using in vitro models were evaluated. Phenolic composition of the seed extracts using reversed phase high performance chromatography (RP-HPLC) and gas chromatography coupled with flame ionization detector (GC-FID) were also assessed. Both extracts exhibited acetylcholinesterase inhibitory activity in a dose-dependent manner (125-1000 μg/mL); however, A. melegueta extract (IC50=373.33 μg/mL) had a significantly higher (p<0.05) acetylcholinesterase inhibitory activity than A. danielli extract (IC50=417.10 μg/mL). Furthermore, both extracts significantly decreased QA-elevated brain malondialdehyde (MDA) contents, reduced Fe3+ to Fe2+ and scavenged DPPH and ABTS radicals. Phenolic characterization of the seeds by RP-HPLC at 280 nm showed abundance of quercetin and kaempferol in A. melegueta and chlorogenic acid in A. danielli, whereas GC-FID revealed that p-hydroxybenzoic acid was abundant in both seeds. Inhibitory effect of these extracts on acetylcholinesterase activity and their antioxidant property could be attributed to the combined effect of phenolic and non-phenolic constituents of the seeds. These effects could be part of the possible biochemical mechanism by which these seeds elicit their protection against oxidative stress in brain; however, A. melegueta showed the more promising potential.

Development and Validation of Stability-Indicating GC-FID Method for the Quantitation of Memantine Hydrochloride and Its Nonchromophoric Impurities in Bulk and Pharmaceutical Dosages

A stability-indicating method has been developed and validated for the quantitative determination of memantine hydrochloride and its nonchromophoric impurities in drug substance and drug product using gas chromatography coupled with flame ionization detector (GC-FID). The stability-indicating nature of the method has been proved by establishing peak purity and confirming the mass balance of all samples by subjecting them to stress conditions like hydrolysis, oxidation, photolysis, and thermal degradation studies. The chromatographic separation was performed on a fused silica capillary (HP-5, 30 meter, 0.32 mm and 0.25 μm film thickness) column. The method validation results indicate that the method has acceptable specificity, accuracy, linearity, precision, robustness, and high sensitivity with detection limits and quantitation limits ranging from 0.001% to 0.01% and 0.004% to 0.03%, respectively. The effectiveness of the technique was demonstrated by analysis of different bulk sample of Memantine hydrochloride. The proposed GC-FID method was also found to be specific and selective for the analysis of commercial formulation samples.

Antimicrobial activity of essential oil of Piper aduncum L. (Piperaceae)

Piper aduncum L. (Piperaceae) is a shrub native from Central to South America used in traditional medicine for the treatment of several deseases. The extract of this species stands out for its interesting biological activities as leishmanicidal, molluscicidal, larvicidal, insecticidal, fungicidal, and antibacterial. The aim of this study was to evaluate the antimicrobial activity of essential oil from leaves of P. aduncum and 1,8-cineole, the major component of the oil, against Pseudomonas aeruginosa, Staphylococcus aureus,Staphylococcus epidermidis, Escherichia coli, and Candida albicans. The essential oil was extracted from fresh leaves by hydrodistillation in a modified Clevenger type apparatus and was subjected to analysis by gas chromatography coupled to flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS). To evaluate the antimicrobial activity, agar well diffusion method (drop test) and micro broth dilution method were used. Analysis of the essential oil allowed the identification of 23 different substances, including monoterpenes (90.4%) and sesquiterpenes (7.0%). The major component was characterized as 1,8-cineole (53.9%). Quantitation with external standard showed a percentage of 47.0% for 1,8-cineole. The essential oil showed significant antibacterial activity against Gram-positive, S. epidermidis and S. aureus, and against the fungus, C. albicans (MIC 100 µg/ml). However, 1,8-cineole was not active, suggesting that the antimicrobial activity may arise from a synergism of other chemical components of essential oil, mainly the monoterpenes. Key words: Piper aduncum, Piperaceae, essential oil, antimicrobial activity.

Determination of the Contamination of Groundwater Sources in Okrika Mainland with Polynuclear Aromatic Hydrocarbons (PAHs)

In this study, we examined the presence and concentrations of six polynuclear aromatic hydrocarbons (PAHs) in groundwater sources of Okrika mainland impacted by effluent discharges from a petroleum refinery into her surrounding Creeks. Sterile amber coloured bottles were used to collect 10 replicate borehole water samples from the mainland and fixed with concentrated H2SO4. Samples were transferred to the laboratory in iced coolers and analyzed using Gas chromatography coupled with Flame Ionization Detector (GC-FID). The interactions of the PAH components detected was determined using the Pearson product moment correlation coefficient (r) while spatial variance equality in means of concentrations was explored with the One-way ANOVA. Structure detection of observed inequalities was made with means plots. Concentrations of the PAHs were high and exceeded the WHO maximum permissible limit of 0.002mg/l in drinking water. Benzo(b)fluoranthene, with the highest mean concentration varied between 0.000370.51266 (0.08117±0.03330159)mg/l, fluoranthene varied between 0.00060-0.32890 (0.0473946±0.01769877)mg/l, while benzo(k)fluoranthene with the least mean concentration varied between 0.00017-0.08478 (0.0237385±0.00610045)mg/l. However, pyrene concentration ranged between 0.00015 and 0.24757 (0.0508440±0.01859716)mg/l, benzo(a)anthracene between 0.00020-0.21972 (0.0512660±0.01688275)mg/l, and chrysene between 0.00013 and 0.16571 (0.0488975±0.01090264)mg/l. Strong associations were observed between all the PAH components measured at P Fcrit(3.921478)] was recorded across the sampling locations at P<0.05. Structure detection of mean difference revealed that the inequalities were most contributed in BH1, BH 2, BH 5 and BH 10, while Research Article

Multivariate optimization of hydrodistillation-headspace solvent microextraction of thymol and carvacrol from Thymus transcaspicus

In this paper multivariate response surface methodology (RSM) has been used for the optimization of hydrodistillation-headspace solvent microextraction (HD-HSME) of thymol and carvacrol in Thymus transcaspicus. Quantitative determination of compounds of interest was performed simultaneously using gas chromatography coupled with flame ionization detector (GC-FID). Parameters affecting the extraction efficiency were assessed and the optimized values were 5min, 2μL and 3min for the extraction time, micro-drop volume and cooling time after extraction, respectively. The amounts of analyte extracted increased with plant weight. The calibration curves were linear in the ranges of 6.25–81.25 and 1.25–87.50mgL−1 for thymol and carvacrol, respectively. Limit of detection (LOD) for thymol and carvacrol was 1.87 and 0.23mgL−1, respectively. Within-day and between-day precisions for both analytes were calculated in three different concentrations and recoveries obtained were in the range of 89–101% and 95–116% for thymol and carvacrol, respectively.

Pollination biology of Jacaranda oxyphylla with an emphasis on staminode function.

Bignoniaceae is a Neotropical family with >100 genera, only two of which, Jacaranda and Digomphia, have a developed staminode. Jacaranda oxyphylla, whose flowers possess a conspicuous glandular staminode, is a zoophilous cerrado species. Here, the composition of the secretion of the glandular trichome and the influence of the staminode on the pollination biology and reproductive success of J. oxyphylla were studied. The floral morphology, pollen viability, stigma receptivity, nectar volume and nectar concentration were studied. Compatibility system experiments were performed and floral visitors were observed and identified. Experiments comparing the effect of staminode presence and absence on pollen removal and pollen deposition efficiency were conducted in open-pollinated flowers. Histochemistry, thin-layer chromatography (TLC) and gas chromatography coupled to flame ionization detection (GC-FID) analyses were performed to determine the main chemical components of the staminode's glandular trichome secretion. Flower anthesis lasted 2 d and, despite the low frequency of flower visitation, pollination seemed to be effected mainly by medium-sized Eulaema nigrita and Bombus morio bees, by the small bee Exomalopsis fulvofasciata and occasionally by hummingbirds. Small bees belonging to the genera Ceratina, Augochlora and Trigona were frequent visitors, collecting pollen. Jacaranda oxyphylla is predominantly allogamous. Staminode removal resulted in fewer pollen grains deposited on stigmas but did not affect total pollen removal. The secretion of capitate glandular trichome occurs continually; the main chemical compounds detected histochemically were phenolic and terpenoid (essential oils and resins). Monoterpene cineole, pentacyclic triterpenes and steroids were identified by TLC and GC-FID. The staminode of J. oxyphyllla is multifunctional and its importance for female reproductive success was attributed mainly to the secretion produced by capitate glandular trichomes. This secretion is involved in complex chemical interactions with pollinating bees, including the solitary bees Euglossini. These bees are common pollinators of various species of Jacaranda.

Solid-Phase Microextraction in Combination with GC--FID for Quantification of the Volatile Free Fatty Acids in Wastewater from Constructed Wetlands

A headspace solid-phase microextraction (HS-SPME) followed by gas chromatography coupled to flame ionization detector (GC-FID) is developed for the direct determination of volatile fatty acids (VFAs) in wastewater from constructed wetlands. Through the investigation on extraction behavior of different coatings for VFAs and the chromatographic behavior of VFAs in a Stabilwax-DA capillary column (30 mx0.32 mm i.d., 0.25 microm film thickness) using nitrogen as carrier gas, the polyacrylate fiber is selected as the satisfactory coating for VFAs analysis, and optimum chromatographic conditions are obtained. The oven temperature is programmed at 70 degrees C for 2 min, then a 4 degrees C/min rate until 180 degrees C, holding 2 min, and then a 20 degrees C/min rate until 200 degrees C, holding the final temperature for 3 min. The various parameters including extraction time, extraction temperature, pH value, ion strength, sample volume, and desorption conditions are investigated for the optimization of HS-SPME performance for VFAs in the wastewater. The experimental results show that the linear dynamic ranges are 10-45000 microg/L, and over two to four orders of magnitude depending on different acids. The detection limit (3sigma) for VFAs are low to microg/L levels and the relative standard deviations are less than 10%, and the recoveries are between 85% and 117%. By using 2-ethylbutyric acid as internal standard, the proposed method is successfully applied to the determination of VFAs in wastewater from the constructed wetlands.

Determination of phthalate esters in cosmetics by gas chromatography with flame ionization detection and mass spectrometric detection

A gas chromatography coupled with flame ionization detection (GC-FID) and mass spectrometric detection (MSD) method was developed to determine the six kinds of phthalate esters [dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DOP)] in cosmetics (solid, cream and liquid cosmetics). The cosmetics were extracted with methanol by ultrasonic and then separated with high-speed centrifugation. The upper clear layer was dried and filtered through a 0.45 mum pore diameter filter. The filtrate was injected into GC-FID/GC-MS for detection. GC-FID chromatogram was applied for qualitative analysis, external standard method was used for quantitative analysis. Confirmation of phthalate presence was undertaken by GC-EI-MS. The recovery range of all phthalates were between 92.0 and 110.0% with relative standard deviations between 1.95 and 5.92%. The low detection limits of the method were: 0.1 ng for DMP, DEP, DBP and BBP, 0.5 ng for DEHP and DOP. The method had advantages of high precision and sensitivity, simplicity of pretreatment. The method can be used to test the six kinds of phthalate esters in cosmetics.

Solid-phase micro extraction (SPME) and headspace derivatization of clenbuterol followed by GC-FID and GC-SIMMS quantification.

Solid-phase micro extraction (SPME) and on-fiber derivatization followed by Gas Chromatography coupled with Flame Ionization Detection (GC-FID) or Selected Ion Monitoring Mass Spectrometry (GC-SIMMS) allows for simple yet sensitive quantification for the hexamethyldisilazane derivative of the beta-agonist clenbuterol. Using an 85- micro m polyacrylate fiber, the analysis method is optimized with respect to extraction time, derivatization time and temperature, and solution pH. In addition, the use of a rapid temperature ramping injection port allows for optimization of fiber desorption conditions. Under optimal conditions, the limits of detection for the hexamethyldisilazane derivative of clenbuterol are 1.1 ppb by FID and 0.20 ppb by SIMMS.