Gas Chromatography-flame Ionization Detection Analysis Research Articles

Differentiation through E-nose and GC-FID data modeling of rosé sparkling wines elaborated via traditional and Charmat methods.

The growing demand for rosé sparkling wine has led to an increase in its production. Traditional or Charmat wine-making influence the aromatic profiles in wine. An analysis such as gas chromatography makes an accurate assessment of wines based on volatile detection but is resource intensive. On the other hand, the electronic nose (E-nose) has emerged as a versatile tool, offering rapid, cost-effective discrimination of wines, and contributing insights into quality and production processes because of its aptitude to perform a global aromatic pattern evaluation. In the present study, rosé sparkling wines were produced using both methods and major volatile compounds and polyols were measured. Wines were tested by E-nose and predictive modelling was performed to distinguish them. Volatile profiles showed differences between Charmat and traditional methods, especially at 5 months of aging. A partial least square discriminant analysis (PLS-DA) was carried out on E-nose detections, obtaining a model that describes 94% of the variability, separating samples in different clusters and correctly identifying different classes. The differences derived from PLS-DA clustering agree with the results obtained by gas-chromatography. Moreover, a principal components regression model was built to verify the ability of the E-nose to non-destructively predict the amount of different volatiles analyzed. Production methods of Rosé sparkling wine affect the final wine aroma profiles as a result of the differences in terms of volatiles. The PLS-DA of the data obtained with E-nose reveals that distinguishing between Charmat and traditional methods is possible. Moreover, predictive models using gas chromatography-flame ionization detection analysis and E-nose highlight the possibility of fast and efficient prediction of volatiles from the E-nose. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Application of Nanocube-Functionalized Nitrogen-Doped Melamine Sponge for Dispersive Micro-Solid Phase Extraction (SPE) of Phenolic Compounds From Aquatic Media

A procedure is reported for the efficient extraction and determination of phenolics from aqueous media. The approach is based on the dispersive micro-solid phase extraction using synthesized Co3O4 nanocube-functionalized nitrogen-doped melamine foam. The adsorption and desorption conditions were optimized by response surface methodology and one-variable-at-a-time approaches. The proposed method was fully validated. Under the optimized conditions, the limits of detection were lower than 0.5 ng mL−1. Calibration curves were linear in the range from 1.0 to 250.0 ng mL−1, 0.7 to 200.0 ng mL−1, 0.2 to 250.0 ng mL−1, and 1.0 to 250.0 ng mL−1 for phenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol, respectively. Enrichment factors and absolute recoveries from 17.5 to 20.7 and 70% to 83% were achieved. The method was successfully applied for trace monitoring of the analytes in environmental and industrial water samples with gas chromatography—flame ionization detection analysis. Satisfactory relative recoveries between 89.0% and 105.8% were obtained along with acceptable precision below 8.1%. This method is a simple, rapid, sensitive, and reliable protocol for efficient screening of the phenolics.

Improvement of methods for analysing sucrose acetate isobutyrate (SAIB) in soft drinks using GC-FID and evaluating antioxidant effects in the SAIB emulsion system

Sucrose acetate isobutyrate SAIB (E444) is a mixture produced by the esterification of sucrose with acetic anhydride and isobutyric anhydride. It is a food additive that is used as an emulsifier in soft drinks. It is difficult to analyse SAIB quantitatively because there are 256 synthesisable structures in the mixture. This study developed an analytical method for SAIB using gas chromatography-flame ionization detection (GC-FID). The pre-treatment of SAIB in soft drinks was performed using a liquid-liquid extraction method, which demonstrated a recovery rate of 107.8 ± 7.2%. In the GC-FID analysis of SAIB, numerous peaks were observed in the chromatogram, and the content of SAIB was calculated as the sum of these peak areas. A series of analytical methods were validated according to International Conference for Harmonization (ICH) guidelines. Accordingly, the applicability of the developed analytical method was confirmed for both domestic and imported soft drinks distributed in Korea. Additionally, in the linoleic acid emulsion, SAIB exhibited better lipid oxidation stability than the natural antioxidant α-tocopherol and had similar efficacy to the synthetic antioxidant butylated hydroxytoluene (BHT). Although SAIB has excellent lipid oxidation stability, it must be used within legal standards according to consumer demand to reduce the use of synthetic materials in processed foods. The validated GC-FID analytical method will enable subsequent monitoring of the distributed products.

Rising above helium: A hydrogen carrier gas chromatography flame ionization detection (GC-FID) method for the simultaneous quantification of toxic alcohols and ethylene glycol in human plasma specimens

Here we validate a GC, Flame Ionization Detection (GC-FID), liquid injection method using hydrogen as a carrier gas combining analysis of toxic volatile alcohols (VA): methanol, ethanol, isopropanol, acetone, as well as glycols, ethylene glycol (EG) and propylene glycol (PG), in a single method. Methodology200 μL of calibrator, QC, or patient specimen were deproteinized with 400 μL of acetonitrile containing internal standards (10 mmol/L N-propyl alcohol for VA and 2.5 mmol/L 1,2-butanediol for glycols). GC-FID analysis using hydrogen carrier gas and nitrogen makeup gas utilized an Agilent 7890 system equipped with Agilent 7683 liquid autosampler on a 30 m × 530 μm RTX-200 fused silica column. Method validation included repeatability, recovery, carryover, linearity, lower limit of quantification (LLOQ), accuracy, selectivity and measurement uncertainty. ResultsThe 8.3 min from injection to injection reduced time of analysis by 45% over a previously reported method using Helium carrier gas with no loss in resolution. Within-run and Between-run variability were ≤1.4% and ≤6.8% respectively. Recovery was 100% within a 95% confidence interval. Carryover was negligible for all but EG. LLOQ was <1 mmol/L for all analytes. The upper range of linearity was 120 mmol/L for methanol, ethanol and isopropanol, 100 mmol/L for acetone and 50 mmol/L for EG. Analytes demonstrated acceptable accuracy and measurement uncertainty using College of American Pathologists (CAP) criteria. Toluene can cause a false positive EG, while benzene, xylene and 1,3 butanediol can cause false negative EG. ConclusionsConverting from Helium to Hydrogen carrier gas benefits patient care through a reduction in turnaround time and provides a cost savings to the laboratory.

Magnetically responsive polycaprolactone nanoparticles for progesterone screening in biological and environmental samples using gas chromatography.

A new Fe3O4/poly(є-caprolactone) (PCL) magnetite nanocomposite was fabricated and used as a sorbent for magnetically mediated PCL microspheres solid-phase extraction (MM-PCL-SPE) followed by gas chromatography-flame ionization detection (GC-FID) for monitoring of progesterone (PGN) hormone in biological and environmental matrices, namely blood serum, tap water, urine, and hospital wastewater. The nanomagnetite core of the sorbent was synthesized by a co-precipitation method. Magnetic nanoparticles (MNPs) were then microencapsulated with PCL microspheres using emulsion polymerization. The nanocomposite was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The magnetite sorbent can be effectively dispersed in aqueous solution and attracted to an external magnetic field. The MM-PCL-SPE process for PGN assay involved (a) dispersion of the sorbent in the donor phase aqueous solution with sonication, (b) exposure to a magnetic field to collect sorbent that had adsorbed the analyte, and (c) solvent desorption of extracted PGN for GC-FID analysis. The work demonstrates the usefulness of MM-PCL-SPE in the rapid and sensitive monitoring of trace amounts of PGN in real samples. The limit of detection (LOD) and limit of quantification (LOQ) were 1.00 and 3.30ng/mL, respectively. The relative recoveries in real samples were adequate. Linearity was observed over a wide range of 2.2-10,000.0ng/mL in aqueous media and urine and 0.01-70.0μg/mL in blood serum. Graphical Abstract In this research new Fe3O4/poly(є-caprolactone) (PCL) magnetite microspheres were developed as an efficient sorbent for solid-phase extraction of progesterone hormone in biological and environmental matrices.

Heterogeneous Ganglioside Standards in LC-MS/MS: Sensitive Method for Quantifying the Major Molecular Components in Mono-Sialo Ganglioside Standards

A commercially-available mono-sialo (GM1) ganglioside standard consists of three major components with different ceramide structures: C18:0 fatty acid/C18-sphingosine, C18:0 fatty acid/C20-sphingosine and C20:0 fatty acid/C18-sphingosine. The usual multiple reaction monitoring (MRM) liquid chromatography-tandem mass spectrometry (LC-MS/MS) of gangliosides, which monitors the dehydrated sialic acid fragment (m/z 290), cannot differentiate between the individual iso-molecular weight components C18:0 fatty acid/C20-sphingosine and C20:0 fatty acid/C18-sphingosine. Present characterization of ganglioside standards quantifies only the fatty acid content by gas chromatography-flame ionization detection (GC-FID) analysis of the ganglioside mixture and does not parse out the percentages of the individual mono-sialo ganglioside components. In the present work analyzing a heterogeneous GM1 standard, results from a dehydrated sialic acid daughter ion MRM LC-MS/MS determination employing hydrophilic interaction liquid chromatography were combined with results of the fatty acid content determined by GC-FID analysis to sensitively quantify the three predominant individual molecular GM1 components in standards at concentrations as low as 50 ng/mL (Method 1). These dehydrated sialic acid MRM results (Method 1) were confirmed by a less sensitive fatty acid daughter ion MRM LC-MS/MS technique (Method 2) which could only determine molecular GM1 components in standards at high concentrations (1 μg/mL-10 μg/mL). Method 2, however, has the advantage of directly quantifying the three predominant individual molecular GM1 components for comparison with Method 1 results. Equations are derived which incorporate the combined data (Method 1) to calculate percentages of individual mono-sialo gangliosides in the standard. Percentages for the individual mono-sialo gangliosides in the standard differed by at most 2% (absolute difference in the percentages) in comparing the results obtained by the two methods.

Atmospheric reactivity of hydroxyl radicals with guaiacol (2-methoxyphenol), a biomass burning emitted compound: Secondary organic aerosol formation and gas-phase oxidation products

Methoxyphenols are low molecular weight semi-volatile polar aromatic compounds produced from the pyrolysis of wood lignin. The reaction of guaiacol (2-methoxyphenol) with hydroxyl radicals has been studied in the LPCA simulation chamber at (294 ± 2) K, atmospheric pressure, low relative humidity (RH < 1%) and under high-NOx conditions using CH3ONO as OH source. The aerosol production was monitored using a SMPS (Scanning Mobility Particle Sizer); the SOA yields were in the range from 0.003 to 0.87 and the organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. Transmission (TEM) and Scanning (SEM) Electron Microscopy observations were performed to characterize the physical state of SOA produced from the OH reaction with guaiacol; they display both liquid and solid particles (in an amorphous state).GC-FID (Gas Chromatography – Flame Ionization Detection) and GC-MS (Gas Chromatography – Mass Spectrometry) analysis show the formation of nitroguaiacol isomers as main oxidation products in the gas- and aerosol-phases. In the gas-phase, the formation yields were (10 ± 2) % for 4-nitroguaiacol (1-hydroxy-2-methoxy-4-nitrobenzene; 4-NG) and (6 ± 2) % for 3- or 6-nitroguaiacol (1-hydroxy-2-methoxy-3-nitrobenzene or 1-hydroxy-2-methoxy-6-nitrobenzene; 3/6-NG; the standards are not commercially available so both isomers cannot be distinguished) whereas in SOA their yield were much lower (≤0.1%).To our knowledge, this work represents the first identification of nitroguaiacols as gaseous oxidation products of the OH reaction with guaiacol. As the reactivity of nitroguaiacols with atmospheric oxidants is probably low, we suggest using them as biomass burning emission gas tracers. The atmospheric implications of the guaiacol + OH reaction are also discussed.

Novel approach to microwave-assisted extraction and micro-solid-phase extraction from soil using graphite fibers as sorbent

A single-step extraction–cleanup procedure involving microwave-assisted extraction (MAE) and micro-solid-phase extraction (μ-SPE) has been developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) from soil samples. μ-SPE is a relatively new extraction procedure that makes use of a sorbent enclosed within a sealed polypropylene membrane envelope. In the present work, for the first time, graphite fiber was used as a sorbent material for extraction. MAE–μ-SPE was used to cleanup sediment samples and to extract and preconcentrate five PAHs in sediment samples prepared as slurries with addition of water. The best extraction conditions comprised of microwave heating at 50 °C for a duration of 20 min, and an elution (desorption) time of 5 min using acetonitrile with sonication. Using gas chromatography (GC)–flame ionization detection (FID), the limits of detection (LODs) of the PAHs ranged between 2.2 and 3.6 ng/g. With GC–mass spectrometry (MS), LODs were between 0.0017 and 0.0057 ng/g. The linear ranges were between 0.1 and 50 or 100 μg/g for GC–FID analysis, and 1 and 500 or 1000 ng/g for GC–MS analysis. Granular activated carbon was also used for the μ-SPE device but was found to be not as efficient in the PAH extraction. The MAE–μ-SPE method was successfully used for the extraction of PAHs in river and marine sediments, demonstrating its applicability to real environmental solid matrixes.

Evaluation of solid adsorbent materials for cryogen-free trapping—gas chromatographic analysis of atmospheric C2–C6 non-methane hydrocarbons

Nine commercial solid adsorbent materials (in order of decreasing surface area: Carboxen 1000, Carbosieve S III, molecular sieve 5A, molecular sieve 4A, silica gel, Carboxen 563, activated alumina, Carbotrap and Carboxen 1016) were investigated for their ability to trap and release C2–C6 non-methane hydrocarbons (NMHCs) in atmospheric samples for subsequent thermal desorption gas chromatography-flame ionization detection analysis (GC-FID). Recovery rates for 23 NMHCs and methyl chloride (CH 3Cl) were determined. A microtrap filled with the three adsorbents Carbosieve S III, Carboxen 563 and Carboxen 1016 was found to allow for the analysis of the widest range of target analytes. A detection limit of approximately 3 pptC [parts per trillion (carbon)] in a 1 l air sample and a linear response over a wide range of volatilities and sample volumes was determined for this configuration. Water vapor in the sample air was found to causes interference in trapping and subsequent chromatographic analysis of light NMHCs. A Peltier-cooled, regenerable water trap inserted into the sample flow path was found to mitigate these problems and to allow quantitative and reproducible results for all analytes at all tested humidity conditions.

Determination of organic molecular markers in marine aerosols and sediments: one-step flash chromatography compound class fractionation and capillary gas chromatographic analysis

n-Alkanes, polycyclic aromatic hydrocarbons (PAHs), n-alkanals, n-alkan-2-ones, long-chain alkenones, oxy-PAHs, n-alkanols, sterols and free alkanoic acids have been reliably determined in various environmental matrices by using one-step flash chromatography compound class fractionation and subsequent gas chromatography (GC)–MS and/or GC–flame ionization detection analysis. The obtained recoveries, for the whole analytical procedure were 62–98% for n-alkanes, 60–100% for PAHs, 75% for n-alkanals, 96–100% for nitroarenes, 65–73% for oxy-PAHs, 88–98% for n-alkanols, 80–89% for steroidal alcohols and 98% for alkanoic acids. This analytical protocol has been applied, and proved suitable, for the determination of more than 170 organic compounds in samples, such as aerosols and marine sediments, collected during a 1 year period in a coastal environment of Eastern Mediterranean.