Capillary Gas-liquid Chromatography Research Articles

Abstract PO1-13-08: Comparative analysis of stearoyl-CoA desaturase 1 expression and activity index in model cell lines of breast cancer subclasses

Abstract Introduction Due to the unique conditions of the tumor microenvironment, such as hypoxia, poor angiogenesis, and mitochondrial dysfunction, cancer cells face challenges in obtaining nutrients and energy supply. However, monounsaturated fatty acids have been identified as preferred substrates for energy generation and maintenance of cellular structures in cancer cells. These fatty acids can be obtained through de novo fatty acid synthesis. Stearoyl-CoA desaturase 1 (SCD1) is the primary enzyme involved in the biosynthesis of monounsaturated fatty acids from saturated fatty acids and is known to be upregulated in various malignancies, including breast cancer. This study aimed to assess the expression and activity index of SCD1 in well-characterized MCF-7, SK-BR3, and MDA-MB231 breast cancer cell lines, representing luminal A/B, HER2-enriched, and triple-negative subtypes, respectively. Methods The breast cancer cell lines were cultured in RPMI-1640 medium with 10% fetal bovine serum at 37°C, 5% CO2, and 95% humidity for 72 hours. After harvesting the cells, SCD1 expression was analyzed using real-time quantitative PCR, and the activity index was determined by measuring the ratio of monounsaturated fatty acids to saturated fatty acids using capillary gas-liquid chromatography. Results MCF-7 cell line showed a significantly higher SCD1 expression compared to MDA-MB231 (250-fold, p< 0.0001) and SK-BR3 (83-fold, p< 0.0001) cell lines. The activity index of SCD1 was significantly higher in both MCF-7 and MDA-MB231 cell lines with fold changes of 2.6 and 2.5, respectively, compared to SK-BR3 cell line (p=0.004 for both). Conclusion Cell model assays demonstrated that the luminal A/B and triple-negative subtypes showed a higher capacity to convert saturated fatty acids to monounsaturated fatty acids through SCD1 enzyme activity, indicating a different lipid metabolism profile in the HER2-enriched subtype. These new findings reveal differences in SCD1 expression and activity among breast cancer subclasses. They highlight vulnerabilities in metabolism and identify potential therapeutic targets with clinical implications for managing breast cancer. Citation Format: Hamid-Reza Feizi, Amir Mehdizadeh, Zohreh Sanaat, Khadijeh Abbasi, Frank Gieseler, Masoud Darabi. Comparative analysis of stearoyl-CoA desaturase 1 expression and activity index in model cell lines of breast cancer subclasses [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-13-08.

Determination of gas-polydimethylsiloxane distribution constants of major Cannabis terpenes and terpenoids by capillary gas-liquid chromatography

Terpenes and terpenoids are the principal responsible for the aroma of Cannabis, playing an important role in the interaction with the environment. Analytical determination of these compounds can be done by headspace coupled to solid phase micro-extraction (HS-SPME) and then injected in a gas chromatograph. In the present study, we determined distribution constants between gas and polydimetylsiloxane (PDMS), a conventional SPME liquid phase, at three temperatures between 303.15 and 343.15 K for major Cannabis terpenes and terpenoids employing a method based in gas chromatography using four capillary columns for monoterpenes and five columns for sesquiterpenes. In addition, van't Hoff regressions (logKfg vs T−1) were obtained in order to estimate logKfg at 298.15 K aiming to compare with bibliographic values (experimental or estimated ones). An excellent agreement was found between them. The method, based on chromatographic theory is robust and relatively simple. It is expected that the herein obtained data could be useful for selecting SPME fiber type and dimensions, estimating extraction efficiencies, as well as to develop prediction models and validate them.

Determination of Gas-Polydimethylsiloxane Distribution Constants of Terpenes and Terpenoids Found in Cannabis Sativa by Capillary Gas-Liquid Chromatography

Determination of Gas-Polydimethylsiloxane Distribution Constants of Terpenes and Terpenoids Found in Cannabis Sativa by Capillary Gas-Liquid Chromatography

The role of α-tocopherol and ɷ-3 polyunsaturated fatty acids in miscarriage at early stages of pregnancy with cytomegalovirus infection

Introduction. It is now generally acknowledged that cytomegalovirus infection (CMVI) is one of the main causes of miscarriage. However, the mechanism of this effect has not been sufficiently studied. At the same time, the influence of acids of the ɷ-3 family and α-tocopherol (αTP) on the placentation process through a pro-angiogenic action is shown.Aim. To study the concentration of αTP and ɷ-3 family acids in the peripheral blood and establish their role in miscarriage in CMV-seropositive women with CMVI reactivation.Materials and methods. A case-control study included 64 women in the first trimester of pregnancy (7-10 weeks), of which 36 were CMV-seropositive with CMVI reactivation (main group) and 28 were CMV-seronegative (control group). CMVI was diagnosed by the determination of class M and G antibodies by ELISA, as well as CMV DNA detected by PCR. The concentration of ɷ-3 acids of the family (eicosapentaenoic – EPA, docosahexaenoic – DHA) in blood serum was studied by capillary gas-liquid chromatography (J.P.Carreau, J.P.Dubacq). The αTP concentration was determined by the fluorometric method (L.G.Hansen, W.I.Warwich).Results. In women of the main group, a significant (p<0.001) decrease in the concentration of αTP to 1.32±0.025 μg/mL was observed in the peripheral blood compared to the same indicator in the control group (1.49±0.029 μg/mL). At the same time, the levels of EPA and DHA were also statistically significant (p<0.001) lower than the same indicator in the control group and amounted to 1.09±0.012 and 6.09±0.015%, respectively (in the control, 1.29±0.071 and 8.80±0.071%, respectively). Conclusion. The obtained results of the study allow us to establish the important role of disorders in the content of α-TF, EPA and DHA in the pathogenesis of miscarriage during reactivation of CMVI in the early periods of gestation, which can serve as a basis for expanding diagnostic and therapeutic measures in this pathology of pregnant women.

Residual amounts of pesticides in citrus fruits: analytical control

Introduction. Thanks to possessing beneficial properties and vitamin content, citrus fruits occupy a prominent place in the ubiquitous nutrition of all ages due to various crops. On the other hand, due to climatic conditions, they cannot be cultivated in our country and are classified as imported products, which justifies the importance of controlling their safety. Purpose of the work. The creation of a multicomponent method for determining the residual amounts of pesticides and their metabolites in citrus fruits. Materials and methods. HPLC with triple quadrupole mass detector in multiple reaction monitoring (MRM) mode and capillary gas-liquid chromatography with mass selective detector (GC-MC) in selected ion monitoring mode (SIM) together were used to perform the identification and quantitative determination of the active substances of pesticides of various classes (amino pyrimidines, imidazoles, carbamates, strobilurins, triazoles, organophosphorus compounds, etc.) As a sample preparation method, there was used the QuEChERS technology, based on the extraction of pesticides with an organic solvent from a homogenized sample in the presence of salts containing citrate buffer and the purification of the extracts by dispersive solid-phase extraction. Results. To control the safety of citrus fruits (lemons, grapefruits, oranges, tangerines) imported from Egypt, Turkey and Abkhazia, purchased on the food market, a multi-method was used for determining the residual amounts of a wide range of pesticide compounds (50 names of active ingredients of pesticides and their toxic metabolites) in citrus fruits. The identified levels of active pesticide ingredients did not exceed the established MRLs. Conclusion. The modern development of the analytical chemistry of pesticides, the use of a tandem of gas and liquid chromatography with mass spectrometric detection made it possible to implement a group method for the quantitative determination of the active substances of pesticides and their toxic metabolites in citrus fruits. Modern development makes it possible to detect the contamination of their residual amounts in the processed products.

NMR Metabolite Profiles in Male Meat-Eaters, Fish-Eaters, Vegetarians and Vegans, and Comparison with MS Metabolite Profiles.

Metabolomics may help to elucidate mechanisms underlying diet-disease relationships and identify novel risk factors for disease. To inform the design and interpretation of such research, evidence on diet-metabolite associations and cross-assay comparisons is needed. We aimed to compare nuclear magnetic resonance (NMR) metabolite profiles between meat-eaters, fish-eaters, vegetarians and vegans, and to compare NMR measurements to those from mass spectrometry (MS), clinical chemistry and capillary gas-liquid chromatography (GC). We quantified 207 serum NMR metabolite measures in 286 male participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford cohort. Using univariate and multivariate analyses, we found that metabolite profiles varied by diet group, especially for vegans; the main differences compared to meat-eaters were lower levels of docosahexaenoic acid, total n-3 and saturated fatty acids, cholesterol and triglycerides in very-low-density lipoproteins, various lipid factions in high-density lipoprotein, sphingomyelins, tyrosine and creatinine, and higher levels of linoleic acid, total n-6, polyunsaturated fatty acids and alanine. Levels in fish-eaters and vegetarians differed by metabolite measure. Concentrations of 13 metabolites measured using both NMR and MS, clinical chemistry or GC were mostly similar. In summary, vegans’ metabolite profiles were markedly different to those of men consuming animal products. The studied metabolomics platforms are complementary, with limited overlap between metabolite classes.

Гербіциди з групи нітродифенілових етерів: застосування в Україні, методи контролю, методика визначення залишків оксифлуорфену в зерні та олії сої

A review of analytical methods for the determination of herbicide residues from the group of nitrodiphenyl ethers in the environment and agricultural products, developed and validated a method for oxyfluorfen determination in soybean grain and oil method GC/ECD, which meets regulatory requirements and solves the problem of toxicant control in the above matrices. The developed method uses modern methods of sample preparation, identification and quantification of oxyfluorfen (selective extraction, capillary gas-liquid chromatography (GC/ECD GC/MS). The method is validated according to EU requirements) (SANTE/12682/2019 quality control and analytical validation procedures for pesticide residues analysis in food and feed). Key words: gas-liquid chromatography, mass spectrometry, herbicides, nitrodiphenyl ethers, control, residual amounts.

Indicators of vascular-endothelial growth factor and docosahexaenoic acid in pregnant women with threatening course of early pregnancy associated with cytomegalovirus

Aim . To determine the indices of vascular endothelial growth factor and docosahexaenoic acid in women with threatened early pregnancy associated with cytomegalovirus infection exacerbation. Materials and methods . The study included 74 women at a gestation period of 7-12 weeks, of which 38 women with exacerbation of cytomegalovirus infection and the onset of spontaneous miscarriage (main group) and 36 without such pathology (control group). The material for the study was peripheral blood, urine, and scraping of the buccal epithelium. Antibodies IgM and G to cytomegalovirus, low avidity IgG (avidity index) were determined by enzyme-linked immunosorbent assay. Cytomegalovirus DNA was detected by real-time PCR analysis. Indicators of vascular endothelial growth factor were established by enzymelinked immunoassay. The concentration of docosahexaenoic acid was analyzed using capillary gas-liquid chromatography. Results . The concentration of vascular endothelial growth factor in the blood serum in pregnant women in the main group was 1.7 times (p<0.001) lower than in the control group. A similar dynamics of changes was established for docosahexaenoic acid, the concentration of which was 1.4 times lower than that of the control group (p<0.001). Conclusion . The data obtained indicate that the exacerbation of cytomegalovirus infection in early pregnancy is associated with a significant decrease in vascular endothelial growth factor and docosahexaenoic acid, which has adverse effects on angiogenesis and growth of placenta, and pregnancy outcome.

A rapid and highly sensitive UPLC-ESI-MS/MS method for the analysis of the fatty acid profile of edible vegetable oils

The analysis of the fatty acid profile of triglycerides has long played a central role in the evaluation and classification of edible vegetable oils. However, the range of analytical procedures available to evaluate these profiles remains limited and are typically based on transesterification of the triglyceride fatty acid residues to methyl esters, followed by capillary gas–liquid chromatography (GC) coupled with flame ionization or mass spectrometry detection. Although robust and long-proven, these analytical methods tend to entail long chromatographic runs and are relatively insensitive. In order to expand the range of available techniques for the analysis of the fatty acid profile of triglycerides in vegetable oils, we report herein a novel method based upon a rapid and straightforward transesterification of the triglycerides with dimethylaminoethanol under alkaline conditions, followed by a “dilute-and-shoot” analysis by ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry. The chromatographic analysis is accomplished in 1.5 min, affording a high throughput of samples compared to techniques based upon GC approaches. The method performance was assessed intra- and inter-day with 10 representative saturated and unsaturated fatty acids ranging from C8 to C18 and afforded fatty acid profile accuracies of 93–108% and imprecisions of only 0.3–2.0%. The limit of quantification of the method, estimated as the minimum amount of derivatized oil sample capable of affording less than 20% accuracy and precision error was determined to be approximately 0.5 pg on-column, making this new method potentially valuable for fields where high sensitivity, precision, and accuracy may be required, such as in toxicology studies, forensics, archeology, or art analysis.

Cyclooxygenase 2 as a Marker of Early Pregnancy Loss in Cytomegalovirus Infection

Background. Increased expression of cyclooxygenase 2 in the placenta plays a significant role in the formation of placental disorders in the pathological course of pregnancy. It was shown that a high level of expression of cyclooxygenase 2 leads to excessive synthesis of prostaglandins, which stimulate the contractile activity of the uterine myometrium and trigger the abortion mechanism. An analysis of modern literature has shown a lack of data proving the involvement of cyclooxygenase 2 in the pathogenesis of early miscarriages in cytomegalovirus infection. Objective. To establish the pathogenetic role of cyclooxygenase 2 in early pregnancy in the course of miscarriage during exacerbation of cytomegalovirus infection. Materials and methods. The study included 86 women with a gestational age of 8–12 weeks, of which 46 women with spontaneous abortion (O03) and exacerbation of cytomegalovirus infection (main group) and 40 women with medical abortion (O04) without cytomegalovirus infection (control group). The material for the study was peripheral blood serum, urine, homogenate of the villous chorion of the placental tissue. The content of cyclooxygenase 2, the level of IgM and IgG antibodies to cytomegalovirus, low-type IgG antibodies to cytomegalovirus (avidity index) were analyzed by enzyme-linked immunosorbent assay; the content of arachidonic acid – by capillary gas-liquid chromatography. Results. During the study, women of the main group found an increase in the concentration of arachidonic acid by 59 % (p < 0.001) and the activity of the lipolytic enzyme cyclooxygenase 2 – by 58 % (p < 0.001) in the placenta villous chorion homogenate. Conclusion. With an exacerbation of cytomegalovirus infection in the homogenate of the villous placenta chorion of pregnant women with spontaneous abortion, an increase in the content of arachidonic acid and the level of cyclooxygenase 2 is observed. An increased level of cyclooxygenase 2 indicates the development of pregnancy complications and can be used as a non-specific marker predictor of pregnancy termination during exacerbation of cytosis.

The role of lipid peroxidation products in the development of iron deficiency anemia in cytomegalovirus infection in pregnant women of the first trimester

Aim. To establish the role of lipid peroxidation (LPO) products in the development of iron deficiency anemia in pregnant women of the first trimester during exacerbation of cytomegalovirus infection. Materials and methods . A prospective case-control study included 60 women in the first trimester of pregnancy (8-12 weeks), of which 35 were cytomegalovirus-positive with mild iron deficiency anemia (main group) and 25 - cytomegalovirus-seronegative (control group). Antibodies of IgM and IgG to CMV, low avid IgG (avidity index), and serum ferritin concentration were determined by enzyme-linked immunosorbent assay. In order to assess the intensity of LPO processes in blood serum spectrophoto-metric method was used to measure the levels of molecular products of oxidation: diene conjugates and active products of thiobarbituric acid. The concentration of arachidonic acid in blood serum was analyzed by means of the method of capillary gas-liquid chromatography. The concentration of total hemoglobin in red blood cells was measured by photometry. The study of iron metabolism included: evaluation of serum iron by spectrophotometric method, the total iron binding capacity of serum using commercial kits of the company “Lachema” (Czech Republic), transferrin saturation coefficient by means of calculation method. Results . Activation of LPO processes was noted in women of the main group, as evidenced by an increase in the concentration of diene conjugates by 1.54 times (p<0.001), active products of thiobarbituric acid by 2.4 times (p<0.001) and arachidonic acid by 1.3 times (p<0.001) compared with similar indicators of the control group. It has been found that hemoglobin levels were reduced by 1.2 times (p<0.001), serum iron and ferritin, respectively, by 1.4 (p<0.001) and 2 times (p<0.001), in the setting of an increase in the total iron binding capacity of serum while reducing the coefficient of iron saturation with transferrin. Conclusion . The data obtained indicate the important role of LPO products in the pathogenesis of iron deficiency anemia during exacerbation of cytomegalovirus infection in the first trimester of gestation.

Amendment to Quality Parameters for Rice Bran Oil in the Codex Standard for Named Vegetable Oils.

The objective of this study is to review the compliance of fatty acid compositions of Thai and India rice bran oil and level of desmethylsterols of Thai crude rice bran oil with the Codex Standard for Named Vegetable Oil (Codex Stan 210-1999). Fatty acid compositions of 90 samples of Thai and India refined rice bran oil were analyzed by capillary gas liquid chromatography. The results indicated that the contents of the C14:0, C18:2, C22:0 and C24:0 possible fall outside the range of Codex Stan 210-1999. In addition, sterol profile content of 40 samples of crude rice bran oil from Thai refinery plants were studied. The test results of major compositions of desmethylsterols are in good agreement with CODEX STAN 210-1999 except for Brassicasterol and other desmethylsterols. Accordingly, these data were proposed to corporate into the codex standard. Consequently, Codex agreed to amend the fatty acid composition of C14:0, C18:2, C22:0 and C24:0 from ND to 1.0, 21 to 42, ND to 1.0 and ND to 0.9 % and broaden level of Brassicasterol and other desmethylsterols to "ND-0.3" and to "7.5-12.8" accordingly.

Получение и характеристика каллусных культур клеток Alhagi persarum Boiss. et Buhse - продуцентов изофлавоноидов

The physiological characteristics of the callus cell cultures of Alhagi persarum Boiss et Buhse, a member of the legume family, widely used in folk medicine, have been studied. It was shown that the source of the explant was an important factor in the initiation of callusogenesis: more intense callusogenesis (almost 100%) was observed for explants from various organs of sterile seedlings, rather than intact plants (less than 30%). As a result, more than 20 lines of morphologically different callus cell cultures were obtained, and the growth parameters for the 5 most intensively growing lines were determined. The composition of fatty acids (FA) of total lipids and secondary metabolites in the most physiologically stable callus line Aр-207 was analyzed. Using capillary gas-liquid chromatography with mass spectrometric detection (GLC-MS), 19 individual C12--C24 FAs were identified, the main fraction of which were palmitic (~ 23%), stearic (~ 22%), linoleic (~ 14%) and α-linolenic (~ 33%) acids. The established atypical ratio of FAs (a simultaneous high content of both saturated FAs and polyunsaturated α-linolenic acid) is possibly due to the adaptation of cells to in vitro growth conditions. Phytochemical analysis of the secondary metabolites was carried out using ultra-performance liquid chromatography with electrospray ionization mass spectrometric detection (UPLC MS). Compounds belonging to different structural groups of isoflavones were found. Aglycones (calycosin, formononetin and afrormosin isomer), glucosides (formononetin glucoside), as well as esters of glucosides (malonylglycosides of calicosin, formononetin, afrormosin isomers, glycitein and genistein) were detected. These secondary metabolites are widespread in plants of the Fabaceae family; however, isoflavones are rare in representatives of the Alhagi genus. The presence of malonylated isoflavone glycosides in Alhagi spp. was shown for the first time. endemic plant species, Alhagi, in vitro cell culture, callus cell culture, isoflavones, fatty acids All studies were carried out using the equipment of the "Experimental Biotechnological Facility" and the "All-Russian Collection of Cell Cultures of Higher Plants" of IРР RAS. This work was supported by the Russian Foundation for Basic Research (RFBR), contract no.18-54-06021 (Az_a), and the Government of the Russian Federation, Megagrant Project no. 075-15-2019-1882.

Applicability of Capillary Gas-Liquid Chromatography for Determination of Parabens in Pharmaceutical Analysis

The traditional gas-liquid chromatography (GLC) method using packed columns is still used in pharmaceutical analysis for determination of parabens, despite the fact that this technique has a number of serious drawbacks.The aim of the study was to develop a more effective capillary GLC method for determination of parabens in active pharmaceutical ingredients and finished pharmaceutical products.Materials and methods: the study was performed using Agilent 6890N and Agilent 7890B systems with flame-ionisation detectors. The systems were equipped with Agilent 7683B and Agilent G4513A autosamplers, respectively. The following columns were used in the study: ZB-1 15 m х 0.32 mm х 0.25 pm, DB-1 30 m х 0.32 mm х 3.0 pm, Cp-Sil 5-CB 30 m х 0.32 mm х 3.0 pm.Results: the authors developed a method for methylparaben and propylparaben determination using capillary column GLC. The chromatographic parameters (chromatographic system performance, reproducibility of peak areas, peak asymmetry) were determined for both capillary and packed column GLC. The authors outlined the prospects for simultaneous determination of several compounds using the proposed method: a four-component mixture containing methyl-, ethyl-, propyl-, and butylparaben was separated in 9 minutes. The authors used Loma Lux Psoriasis to perform partial validation of the test method. They determined the linearity range and the limit of quantitation for methylparaben and propylparaben, and verified accuracy and intermediate precision of the test method.Conclusions: the results of the study allowed for selection of optimal chromatographic conditions for rapid and high-precision determination of methylparaben and propylparaben in medicinal products. The developed method is recommended for control of the content of these compounds in medicinal products.

Human Milk Fatty Acid Composition Is Associated with Dietary, Genetic, Sociodemographic and Environmental Factors in the CHILD Cohort (P08-114-19)

ObjectivesHuman milk fatty acids impact infant growth and development, and their composition is highly variable. We aimed to characterize milk fatty acid composition in a large pregnancy cohort and identify factors that influence their variability. MethodsAmong 1094 mothers from the CHILD cohort, we analyzed milk collected at 3–4 months postpartum. Fatty acids were measured by high-resolution capillary gas-liquid chromatography. Individual fatty acids, total saturated (SFA), monounsaturated (MUFA), n3 and n6-polyunsaturated fatty acids (n3-PUFA and n6-PUFA) were analyzed as standard deviation scores and using principal components analysis (PCA). Maternal diet, sociodemographic, health and environmental factors were self-reported. Single-nucleotide polymorphisms were assessed in genes encoding fatty acid desaturase 1 (FADS1 rs174556) and FADS2 (rs174575). ResultsUsing PCA, we identified four milk fatty acid patterns: ‘MUFA and low SFA’, ‘high n6-PUFA’, ‘high n3-PUFA’ and ‘high medium-chain fatty acids’. In multivariable-adjusted analyses, fish oil supplementation and fatty cold water fish intake were positively associated with docosohexanoic acid and the “high-n3-PUFA” pattern. Mothers carrying the minor allele of FADS1 rs174556 (C > T) had lower proportions of arachidonic acid (ARA). Independent of dietary and genetic factors, Asian ethnicity was associated with higher linoleic acid and total n3-PUFA. Ethnic differences in ARA were explained by the FADS1 genotype. Maternal obesity was independently associated with higher total SFA and ‘high medium-chain fatty acid’ pattern, and lower total MUFA. Lactation stage, season, study site, and maternal education were also independently associated with some milk fatty acids. No associations were observed for maternal age, parity, smoking, delivery mode, or infant sex. ConclusionsThese results suggest that a combination of diet, genetics, sociodemographic, health and environmental factors influence human milk fatty acid patterns. Together, these factors explained about 25% of the variation observed in n3-PUFAs and n6-PUFAs and about 10% of the variation observed in SFAs and MUFAs. Implications of these findings for maternal and infant health requires further research. Funding SourcesManitoba Medical Service Foundation; Children’s Hospital Research Institute of Manitoba; CIHR; AllerGen.

The Effects of Frying Time and Temperatures on Fatty Acids Profile of Blanched Potato Chips

The aim of this research was to study whether the frying time and temperature affected fatty acids profiles of blanched potato chips. Factorial designs were carried out using a completely randomized design (CRD) two factor (time and temperature) and three levels with two replications. Frying temperature was set up at 160 0C, 180 0C and 200 0C. The potato chips were fried for 3, 5, 7 minutes. The oil type used was sunflower. The fatty acids profiles were analyses with capillary gas liquid chromatography (Varian 3400) equipped with an auto sampler and a flame ionization detector (FID) using a 50 m x 0.32 mm (I.D) fused silica bonded phase capillary column (BPX70, SGE, Melbourne, Australia). The experiments were run in duplicate and the present results are the average of the obtained values. ANOVA analysis of the results was carried out using SPSS software (version 11, 2004). The key plot software for making three dimensions was the sigma plot scientific graphing software.&#x0D; The results showed moisture content and colour index of blanched potato chips decreased significantly with increasing frying time and temperature. Furthermore, unsaturated fatty acids (cis oleic and linoleic) decrease after long period frying.

Formation of Petroleum Hydrocarbons from Prokaryote Biomass: 2. Formation of Petroleum Hydrocarbon Biomarkers from Biomass of Geobacillus jurassicus Bacteria Isolated from Crude Oil

The participation of the Geobacillus jurassicus DS1T bacteria, isolated from the Dagang oilfield (PRC), in the formation of hydrocarbons of the Dagang oil has been shown. Saturated hydrocarbon biomarkers (n-alkanes, isoprenanes, steranes, and terpanes) have been identified by capillary gas-liquid chromatography and gas chromatography–mass spectrometry in the soluble part and products of thermolysis of the insoluble part (kerogen) of the Geobacillus jurassicus bacteria biomass, with the distribution of biomarkers corresponding to weakly transformed marine organic matter and being close to that in the initial oil. Squalene has been found in all samples, including the source oil.

METHODOLOGICAL RECEPTION FOR DETERMINATION OF DICAMBA RESIDUES IN SOYBEANS BY GC-MS

Introduction. In this paper, there are presented results of investigations on the development and validation of the method for the determination of dicamba residues in import foodstuff (soybeans). The identification and quantitative determination of dicamba are performed by capillary gas-liquid chromatography with mass-selective detection (ionization-electron impact). Material and methods. The stages of sample preparation include four steps as extraction with acidified acetonitrile, followed by the filtration and evaporation; freezing the sample with filtration and evaporation; dissolving the dry residue in a mixture of acetone: water (1:20); purification by repeated redistribution in a system of immiscible solvents under varying the pH of the aqueous medium (pH 9-10: dichloromethane, hexane, pH 2: hexane-tert-butyl methyl ether). The chromatographic measurement was preceded by the derivatization of the acid to the corresponding methyl ester by the treatment with a solution of diazomethane in diethyl ether Results. The lower limit of the quantitative evaluation of dicamba in samples of soybean beans is of 0.01 mg/kg, the signal-to-noise ratio at the detection limit accounts of 20:1. The completeness of extraction of dicamba, established on the basis of analysis of model samples with the introduction of a substance at four points within the defined range, amounted to 85-95%. The average quadratic deviation of the repetition varies in the range of 3.3-4.9%. Discussion. The use of diethyl ether containing dibutylhydroxytoluene (6 ppm) as a stabilizer, as well as the interfering effect of phthalates, led to the formation of poorly resolved peaks of the methyl ester of dicamba, dibutylhydroxytoluene, and dibutyl phthalate. The combination of the use of different methods of data collection (in the scanning mode and in the mode of recording individual ions) made it possible to identify these components. Replacement of the used diethyl ether, as well as variation of chromatographic conditions, for separation of dicamba and phthalate peaks, made it possible to achieve the necessary selectivity of detection of the analyte.

Энантиоселективность новых неподвижных фаз на основе ионных жидкостей с анионами на основе L-аминокислот

В связи с постоянным расширением возможностей инструментальных методов анализа, в том числе и газовой хроматографии (ГХ), происходит постоянный поиск новых хроматографических материалов расширяющих возможности метода. Это касается и хиральных фаз, где существующий ассортимент энантиоселективных капиллярных колонок достаточно ограничен. В данной работе поставлена цель получения и изучения селективности новых хиральных фаз на основе имидазолевых ионных жидкостей (ИЖ) с анионами на основе L-аминокислот. Впервые использованы ИЖ с хиральным анионом на основе аминокислоты в качестве материала для капиллярных колонок. Показано, что использование данного варианта хиральной НЖФ позволяет получать коэффициенты энантиоселективности того же порядка что и для циклодекстриновых НЖФ и достигать хорошей селективности для аминов

Fatty Acid Content and Composition of Triacylglycerols of Chlorella kessleri.

Triacylglycerols (TAGs) are esters formed from one glycerol and three fatty acids. TAGs are induced to accumulate in algal cells under environmental stress conditions including nutrient-limitation, hyperosmosis, and low temperature, for the storage of metabolic energy and carbon, and also for the consumption of excess energy (e.g., Hirai et al., 2016 ; Hayashi et al., 2017 ). Beside their physiological significance, the commercial utilization of algal TAG has been expected for the production of biodiesel, the methyl esters of fatty acids, from the aspect of carbon-neutral conception. The amounts of TAGs can be determined through quantitative measurement of their constituent fatty acids. This protocol consists of the following three parts: the first is the extraction of total lipids from algal cells with the use of organic solvents, chloroform and methanol, according to the method of Bligh and Dyer (1959), the second is the separation of TAG from the other lipid classes by thin-layer chromatography (TLC), and the third is the production of methyl-esterified derivatives of their constitutive fatty acids and subsequent quantitation of them by capillary gas-liquid chromatography (GLC). This protocol adapted from Sato and Tsuzuki (2011) is used for TAG analysis in a green alga, Chlorella kessleri.