The composition of chemicals and anti-osteogenic properties in the volatile extracts from Homalomena gigantea rhizome.

In this study, the anti-osteogenic properties of the volatile oil extracted from Homalomena gigantea rhizome using ethyl acetate (EtOAc) and methanol (MeOH) were examined. Gas chromatography-mass spectrometry (GC-MS) was employed for the identification of volatile components. Following this, bioassays were performed to evaluate their effects on osteogenesis, encompassing parameters like cell viability, osteoblast differentiation, collagen synthesis and mineralization. The GC-MS analysis revealed 19 compounds in the EtOAc extract and 36 compounds in the MeOH extract. In the MeOH extract, major constituents included bis(2-ethylhexyl) terephthalate (13.83%), linalool (9.58%), palmitic acid (6.55%) and stearic acid (4.29%). The EtOAc extract contained bis(2-ethylhexyl) terephthalate (16.64%), palmitic acid (5.60%) and stearic acid (3.11%) as the predominant components. Both the EtOAc and MeOH extracts of H. gigantea exhibited promising potential for further investigation in anti-osteoporosis research. These findings contribute to the exploration of natural compounds with potential anti-osteoporotic properties, expanding our understanding of their therapeutic potential.

Characterization of Key Aroma Compounds and Main Contributing Amino Acids in Hot-Pressed Oil Prepared from Various Peanut Varieties.

The production of peanut oil in the industrial sector necessitates the utilization of diverse raw materials to generate consistent batches with stable flavor profiles, thereby leading to an increased focus on understanding the correlation between raw materials and flavor characteristics. In this study, sensory evaluations, headspace solid-phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC-MS), odor activity value (OAV) calculations, and correlation analysis were employed to investigate the flavors and main contributing amino acids of hot-pressed oils derived from different peanut varieties. The results confirmed that the levels of alcohols, aldehydes, and heterocyclic compounds in peanut oil varied among nine different peanut varieties under identical processing conditions. The OAVs of 25 key aroma compounds, such as methylthiol, 3-ethyl-2,5-dimethylpyrazine, and 2,3-glutarone, exceeded a value of 1. The sensory evaluations and flavor content analysis demonstrated that pyrazines significantly influenced the flavor profile of the peanut oil. The concentrations of 11 amino acids showed a strong correlation with the levels of pyrazines. Notably, phenylalanine, lysine, glutamic acid, arginine, and isoleucine demonstrated significant associations with both pyrazine and nut flavors. These findings will provide valuable insights for enhancing the sensory attributes of peanut oil and selecting optimal raw peanuts for its production.

A Comparison between Bulgarian Tanacetum parthenium Essential Oil from Two Different Locations.

Tanacetum parthenium L. (Asteraceae) is a perennial herbaceous plant with a long-standing historical use in traditional medicine. Recently Tanacetum parthenium L. essential oil has been associated with a promising potential for future applications in the pharmaceutical industry, in the cosmetics industry, and in agriculture. Investigations on the essential oil (EO) have indicated antimicrobial, antioxidant, and repellent activity. The present study aimed to evaluate the chemical composition of Bulgarian T. parthenium essential oil from two different regions, to compare the results to those reported previously in the literature, and to point out some of its future applications. The essential oils of the air-dried flowering aerial parts were obtained by hydrodistillation using a Clevenger-type apparatus. The chemical composition was evaluated using gas chromatography with mass spectrometry (GC-MS). It was established that the oxygenated monoterpenes were the predominant terpene class, followed by the monoterpene hydrocarbons. Significant qualitative and quantitative differences between both samples were revealed. Camphor (50.90%), camphene (16.12%), and bornyl acetate (6.05%) were the major constituents in the feverfew EO from the western Rhodope Mountains, while in the EO from the central Balkan mountains camphor (45.54%), trans-chrysanthenyl acetate (13.87%), and camphene (13.03%) were the most abundant components.

Chemical Characterization of the Essential Oil Compositions of Mentha spicata and M. longifolia ssp. cyprica from the Mediterranean Basin and Multivariate Statistical Analyses.

This present study aims to characterize the essential oil compositions of the aerial parts of M. spicata L. and endemic M. longifolia ssp. cyprica (Heinr. Braun) Harley by using GC-FID and GC/MS analyses simultaneously. In addition, it aims to perform multivariate statistical analysis by comparing with the existing literature, emphasizing the literature published within the last two decades, conducted on both species growing within the Mediterranean Basin. The major essential oil components of M. spicata were determined as carvone (67.8%) and limonene (10.6%), while the major compounds of M. longifolia ssp. cyprica essential oil were pulegone (64.8%) and 1,8-cineole (10.0%). As a result of statistical analysis, three clades were determined for M. spicata: a carvone-rich chemotype, a carvone/trans-carveol chemotype, and a pulegone/menthone chemotype, with the present study result belonging to the carvone-rich chemotype. Carvone was a primary determinant of chemotype, along with menthone, pulegone, and trans-carveol. In M. longifolia, the primary determinants of chemotype were identified as pulegone and menthone, with three chemotype clades being pulegone-rich, combined menthone/pulegone, and combined menthone/pulegone with caryophyllene enrichment. The primary determinants of chemotype were menthone, pulegone, and caryophyllene. The present study result belongs to pulegone-rich chemotype.

Shoots and Turions of Aquatic Plants as a Source of Fatty Acids.

BACKGROUND: Fatty acids are essential for human health. Currently, there is a search for alternative sources of fatty acids that could supplement such sources as staple crops or fishes. Turions of aquatic plants accumulate a variety of substances such as starch, free sugars, amino acids, reserve proteins and lipids. Our aim is to see if turions can be a valuable source of fatty acids. METHODS: Overwintering shoots and turions of aquatic carnivorous plants were collected. The plant material was extracted with hexane. The oils were analyzed using a gas chromatograph with mass spectrometer. RESULTS: The dominant compound in all samples was linolenic acid. The oil content was different in turions and shoots. The oil content of the shoots was higher than that of the turions, but the proportion of fatty acids in the oils from the shoots was low in contrast to the oils from the turions. The turions of Utricularia species were shown to be composed of about 50% fatty acids. CONCLUSIONS: The turions of Utricularia species can be used to obtain oil with unsaturated fatty acids. In addition, the high fatty acid content of turions may explain their ability to survive at low temperatures.

Amine Switchable Hydrophilic Solvent Vortex-Assisted Homogeneous Liquid-Liquid Microextraction and GC-MS for the Enrichment and Determination of 2, 6-DIPA Additive in Biodegradable Film.

2, 6-diisopropylaniline (2, 6-DIPA) is a crucial non-intentionally organic additive that allows the assessment of the production processes, formulation qualities, and performance variations in biodegradable mulching film. Moreover, its release into the environment may have certain effects on human health. Hence, this study developed simultaneous heating hydrolysis-extraction and amine switchable hydrophilic solvent vortex-assisted homogeneous liquid-liquid microextraction for the gas chromatography-mass spectrometry analysis of the 2, 6-DIPA additive and its corresponding isocyanates in poly(butylene adipate-co-terephthalate) (PBAT) biodegradable agricultural mulching films. The heating hydrolysis-extraction conditions and factors influencing the efficiency of homogeneous liquid-liquid microextraction, such as the type and volume of amine, homogeneous-phase and phase separation transition pH, and extraction time were investigated and optimized. The optimum heating hydrolysis-extraction conditions were found to be a H2SO4 concentration of 2.5 M, heating temperature of 87.8 °C, and hydrolysis-extraction time of 3.0 h. As a switchable hydrophilic solvent, dipropylamine does not require a dispersant. Vortex assistance is helpful to speed up the extraction. Under the optimum experimental conditions, this method exhibits a better linearity (0.0144~7.200 µg mL-1 with R = 0.9986), low limit of detection and quantification (0.0033 µg g-1 and 0.0103 µg g-1), high extraction recovery (92.5~105.4%), desirable intra- and inter-day precision (relative standard deviation less than 4.1% and 4.7%), and high enrichment factor (90.9). Finally, this method was successfully applied to detect the content of the additive 2, 6-DIPA in PBAT biodegradable agricultural mulching films, thus facilitating production process monitoring or safety assessments.

Unveiling the Role of Nano-Formulated Red Algae Extract in Cancer Management.

Cancer is one of the major causes of death, and its negative impact continues to rise globally. Chemotherapy, which is the most common therapy, has several limitations due to its tremendous side effects. Therefore, developing an alternate therapeutic agent with high biocompatibility is indeed needed. The anti-oxidative effects and bioactivities of several different crude extracts of marine algae have been evaluated both in vitro and in vivo. In the present study, we synthesized the aqueous extract (HA) from the marine algae Amphiroa anceps, and then, a liposome was formulated for that extract (NHA). The extracts were characterized using different photophysical tools like dynamic light scattering, UV-visible spectroscopy, FTIR, scanning electron microscopy, and GC-MS analysis. The SEM image revealed a size range of 112-185 nm for NHA and the GC-MS results showed the presence of octadecanoic acid and n-Hexadecanoic acid in the majority. The anticancer activity was studied using A549 cells, and the NHA inhibited the cancer cells dose-dependently, with the highest killing of 92% at 100 µg/mL. The in vivo studies in the zebrafish model showed that neither the HA nor NHA of Amphiroa anceps showed any teratogenic effect. The outcome of our study showed that NHA can be a potential drug candidate for inhibiting cancer with good biocompatibility up to a dose of 100 µg/mL.

Simultaneous Analysis of 272 Pesticides in Agricultural Products by the QuEChERS Method and Gas Chromatography with Tandem Mass Spectrometry.

The aim of this study is to develop a rapid and accurate method for simultaneous analysis of multi-residue pesticides and conduct pesticide monitoring in agricultural products produced by the production and distribution stage in Korea. The representative agricultural products were selected as brown rice, soybean, potato, mandarin, and green pepper and developed using gas chromatography with tandem mass (GC-MS/MS) for the analysis of 272 pesticide residues. The experimental samples were extracted by the QuEChERS-EN method and then cleaned up by using d-SPE, including MgSO4 and primary secondary amine (PSA) sorbents. The established method was validated in accordance with Codex CAC-GL/40, and the limit of quantitation (LOQ) was determined to be 0.01 mg/kg. A total of 243 pesticides satisfied the guidelines in five samples at three levels with values of 60 to 120% (recovery) and ≤45% (coefficient of variation, CV). The remaining 29 pesticides did not satisfy the guidelines, and these pesticides are expected to be used as a screening method for the routine inspection of agricultural products. As a result of analyzing 223 agricultural products in South Korea by applying the simultaneous analysis method, none of the detected levels in the samples exceeded the standard values based on maximum residue limits (MRLs). The developed method in this study will be used to inspect residual pesticides in agricultural products, and it is anticipated to contribute to the distribution of safe agricultural products to consumers.

Phytochemical Characterization, Antioxidant, and Antimicrobial Activity of the Vegetative Buds from Romanian Spruce, Picea abies (L.) H. Karst.

This study aims to investigate the vegetative buds from Picea abies (spruce), naturally found in a central region of Romania, through a comprehensive analysis of the chemical composition to identify bioactive compounds responsible for pharmacological properties. Using HPLC/derivatization technique of GC-MS and quantitative spectrophotometric assays, the phenolic profile, and main components of an ethanolic extract from the buds were investigated. The essential oil was characterized by GC-MS. Moreover, the antioxidant activity with the DPPH method, and the antimicrobial activity were tested. Heavy metal detection was performed by graphite furnace atomic absorption spectrometry. The main components of the alcoholic extract were astragalin, quercetin, kaempferol, shikimic acid, and quinic acid. A total content of 25.32 ± 2.65 mg gallic acid equivalent per gram of dry plant (mg GAE/g DW) and of 10.54 ± 0.083 mg rutin equivalents/g of dry plant (mg RE/g DW) were found. The essential oil had D-limonene, α-cadinol, δ-cadinene, 13-epimanool, and δ-3-carene as predominant components. The spruce vegetative buds exhibited significant antioxidant activity (IC50 of 53 µg/mL) and antimicrobial effects against Staphylococcus aureus. Furthermore, concentrations of heavy metals Pb and Cd were below detection limits, suggesting that the material was free from potentially harmful contaminants. The results confirmed the potential of this indigenous species to be used as a source of compounds with pharmacological utilities.

No sex difference in preen oil chemical composition during incubation in Kentish plovers.

Preen oil, the secretion from the uropygial gland of birds, may have a specific function in incubation. Consistent with this, during incubation, the chemical composition of preen oil is more likely to differ between sexes in species where only one sex incubates than in species where both sexes incubate. In this study, we tested the generality of this apparent difference, by investigating sex differences in the preen oil composition of a shorebird species, the Kentish plover (Anarhynchus, formerly Charadrius, alexandrinus). As both sexes incubate in this species, we predicted the absence of sex differences in preen oil composition during incubation. In the field, we sampled preen oil from nine females and 11 males during incubation, which we analysed with gas chromatography-mass spectrometry (GC-MS). Consistent with predictions, we found no sex difference in preen oil composition, neither in beta diversity (Bray-Curtis dissimilarities) nor in alpha diversity (Shannon index and number of substances). Based on these results, we cannot conclude whether preen oil has a function during incubation in Kentish plovers. Still, we discuss hypothetical roles, such as olfactory crypsis, protection against ectoparasites or olfactory intraspecific communication, which remain to be tested.

Chemical composition and anti-angiogenic activity of the essential oil from Blumea eriantha D.C.

Blumea eriantha D.C is a weed from Asteraceae family and is reported to have anticancer activity. The essential oil from the aerial parts was extracted by steam distillation method with the yield of 0.36%. Through GC-MS analysis of the oil, seventeen compounds could be identified by comparing with linear retention indices with the library. Out of the seventeen compounds ß-Caryophylline oxide was isolated by column chromatography with gradient elution and the structure was determined through FT-IR, MS, 1HNMR, 13 C NMR and DEPT. The oil was evaluated for its effect on angiogenesis using Chorioallantoic Membrane Assay (CAM Assay). The concentration dependent antiangiogenic effect was observed with IC 50 value of 19.28 ppm.

Phytochemical investigation of the n-hexane-extracted oil from four umbelliferous vegetables using GC/MS analysis in the context of antibacterial activity.

Umbelliferous (Apiaceae) vegetables are widely consumed worldwide for their nutritive and health benefits. The main goal of the current study is to explore the compositional heterogeneity in four dried umbelliferous vegetables viz, celery, coriander, dill, and parsley targeting their volatile profile using gas chromatography-mass spectrometry (GC-MS). A total of 133 volatile metabolites were detected belonging to 12 classes. Aromatic hydrocarbons were detected as the major components of the analyzed vegetables accounting ca. 64.0, 62.4, 59.5, and 47.8% in parsley, dill, celery, and coriander, respectively. Aliphatic hydrocarbons were detected at ca. 6.39, 8.21, 6.16, and 6.79% in parsley, dill, celery, and coriander, respectively. Polyunsaturated fatty acids (PUFA) of various health benefits were detected in parsley and represented by roughanic acid and α-linolenic acid at 4.99 and 0.47%, respectively. Myristicin and frambinone were detected only in parsley at 0.45 and 0.56%. Investigation of antibacterial activity of umbelliferous vegetables n-hexane extract revealed a moderate antibacterial activity against Gram-positive and Gram-negative bacteria with higher activity for celery and dill against Staphylococcus aureus with inhibition zone 20.3 mm compared to 24.3 mm of the standard antibacterial drug.

GC/MS-based untargeted metabolomics reveals the differential metabolites for discriminating vintage of Chenxiang-type baijiu.

The "outstanding and unique aged aroma" of Chinese Chenxiang-type baijiu (CXB)-Daoguang 25 (DG25) mainly originates from a "extraordinary storage technology" of Mujiuhai (a wooden container), so it is mysterious and interesting. In this study, an untargeted GC/MS-based metabolomics was used to reveals the volatile differential metabolites for discriminating six different vintages of DG25 combing with chemometrics. A total of 100 volatile metabolites (including unknowns) were extracted and identified, including esters (41%), alcohols (10%) and acids (7%) so on. Finally, 33 differential metabolites were identified as aging-markers. Among them, 25 aging-markers showed a downtrend, including 17 esters such as ethyl acetate, ethyl hexanoate and ethyl palmitate so on. Moreover, it was interesting and to further study that furans showed a significant downtrend. Statistically speaking, ethyl benzoate played an important role in discriminating vintage of 1Y and 3Y, and the other 24 differential metabolites with downtrend discriminating the unstored (0Y-aged) DG25. Eight differential metabolites, such as ethyl octanoate, benzaldehyde, 3-methylbutanol and 1,1-diethoxyaccetal so on increased during aging of DG25, and they played a statistical role in discriminating the 5Y-, 10Y- and 20Y-aged DG25. This study provides a theoretical basis way for the formation mechanism of aging aroma for CXB.

The dynamic changes in volatile metabolites provide a new understanding for the special flavor formation in z. Mioga flower buds during the growth stages.

Although Z. mioga flower buds are popular among consumers for its unique spicy flavor, high nutritional and medicinal value, there are few reports on the formation and changes of the flavor during its growth and maturation process. The understanding of the profile of volatile compounds would help to unravel the flavor formation for Z. mioga flower buds during growth. The volatile changes in Z. mioga flower buds were analyzed by GC-MS and a total of 182 volatile compounds identified, and the terpenoids accounted for the most abundant volatile substances. Almost all the identified volatiles presented an intuitive upward trend throughout the growth period and reached the maximum at the later stage of development (DS3 or DS4). Regarding the PCA and HCA results, there were significant differences found among the four stages, and the DS3 was the critical node. The top 50 differential volatiles screened by OPLS-DA and PLS-DA were all up-regulated, and the correlation analysis indicated that terpenoids might synergize with other chemical types of volatiles to jointly affect the flavor formation of Z. mioga flower buds during growth. The association network for flavor omics revealed that the most important sensory flavor for Z. mioga flower buds were woody and sweet, and the main contribution compounds for the unique flavor contained ß-guaiene, ß-farnesene, δ-cadinene and citronellyl isobutanoate. Taken together, the results of this study provided a reference for flavor quality evaluation of flower buds and determination of the best harvest period.

Thermal oxidation mechanism of palmitic aicd.

The oxidation and degradation of fats lead to a decrease in the nutritional value of food and pose safety concerns. Saturated fatty acids also hold a significant position in the field of lipid oxidation. In this study, the oxidation products of methyl palmitate were investigated by using gas chromatography mass spectrometry (GC-MS). Seven monohydroperoxides and 72 secondary oxidation products were detected. Combined with density functional theory (DFT) calculations, the formation mechanisms of oxidation products can be summarized into four stages. The initial stage involved the formation of monohydroperoxides and alkanes, followed by the subsequent stage involving methyl x-oxo(hydroxy)hexadecanoates. The third stage involved the formation of methyl ketones, carboxylic acids, and aldehydes, while the final stage involved lactones. Meanwhile, methyl ketones were the most abundant oxidation product, approximately 25 times more abundant than aldehydes; the calculated results agreed well with the experimental results. The establishment of a comprehensive thermal oxidation mechanism for palmitic acid provided a new foundation for future lipid oxidation analyses.

Revealing the intrinsic relationship between microbial communities and physicochemical properties during ripening of Xuanwei ham.

To clarify the relationship between microorganisms and physicochemical indicators of Xuanwei ham. Six ham samples for the first, second and third year were selected, respectively. The changes of physicochemical properties, the free fatty acids and microbial communities of Xuanwei ham were investigated by GC-MS and high-throughput sequencing technology. Results showed that scores of colour, overall acceptability, texture, taste and aroma were the highest in the third year sample. With increasing ripening time, moisture content, water activity (Aw), lightness (L*), springiness, and resilience decreased continuously, and yellowness (b*) was the highest in the second year sample. 31 free fatty acids were detected, and unsaturated fatty acids such as palmitoleic acid, oleic acid, and linoleic acid were the major fatty acids. The content of palmitoleic acid, oleic acid and eicosenoic acid increased significantly during processing. At the phylum level, the dominant bacteria were Proteobacteria and Firmicutes, and fungi were Ascomycota. At the genus level, the dominant bacteria were Staphylococcus and Psychrobacter, and fungi were Aspergillus. Correlation analysis showed that water content and Aw were closely related to microorganisms, and most unsaturated fatty acids were significantly correlated with microorganisms. These findings showed that microorganisms played an important role in the quality of Xuanwei ham, and provided a scientific basis for the quality control of Xuanwei ham.

Structural characteristics and in vitro starch digestibility of oil-modified cooked rice with varied addition manipulations.

Lipid has crucial applications in improving the quality of starchy products during heat processing. Herein, the influence of lipid modification and thermal treatment on the physicochemical properties and starch digestibility of cooked rice prepared with varied addition manipulations was investigated. Rice bran oil (RO) and medium chain triglyceride oil (MO) manipulations were performed either before (BC) or after cooking (AC). GC-MS was applied to determine the fatty acid profiles. Nutritional quality was analyzed by quantifying total phenolics, atherogenic, and thrombogenic indices. All complexes exhibited higher surface firmness, a soft core, and less adhesive. FTIR spectrum demonstrated that the guest component affected some of the dense structural attributes of V-amylose. The kinetic constant was in the range between 0.47 and 0.86 min-1 wherein before mode presented a higher value. The lowest glucose release was observed in the RO_BC sample, whereas the highest complexing index was observed in the RO_AC sample, indicating that the dense molecular configuration of complexes that could resist enzymatic digestion was more critical than the quantity of complex formation. Despite the damage caused by mass and heat transfer, physical barrier, intact granule forms, and strengthened dense structure were the central contributors affecting the digestion characteristics of lipid-starch complexes.

Evaluation of the cytotoxic activities of the essential oil from Pistacia atlantica Desf. oleoresin on human gastric cancer cell lines.

Numerous herbal products have been the subject of research regarding their potential role in cancer prevention or adjuvant therapy. Pistacia atlantica and its main phytochemicals have garnered significant attention for their potential anti-cancer effects. The study aimed to assess the growth inhibitory effects of P. atlantica essential oil (PAEO) on MKN-45 and AGS cells. This study quantified the volatile compounds in PAEO using Gas Chromatography-Mass Spectrometry (GC-MS). Subsequently, MKN-45 and AGS cells were treated with varying concentrations of PAEO (5%, 2.5%, 1.25%, 0.625%, 0.3125%, 0.156%, 0.0781%, 0.0391%, 0.0195%) for 24 h. Cell viability was evaluated through the MTT assay. The impact of PAEO on gene expression was investigated by quantifying the mRNA levels of Bax and Bcl2 in the various experimental groups using quantitative Real-Time PCR (qRT-PCR) analysis. Additionally, flow cytometry was utilized to evaluate apoptosis in the treated cells. The analysis of PAEO revealed that α-pinene was the predominant monoterpene, constituting 87.9% of the oil composition. The cytotoxic effects of PAEO were evaluated, and it was found that the oil significantly reduced the viability of MKN-45 and AGS cells. The IC50 for MKN-45 cells was determined to be 1.94 × 10-3% after 24 h of treatment, while for AGS cells the IC50 was 2.8 × 10-3% after 24 h. Additionally, the research revealed that PAEO triggered a notable rise in apoptotic cells in both AGS and MKN-45 cell lines. Moreover, at the molecular level, the findings indicated an increase in Bax expression and a decrease in Bcl2 mRNA expression, providing further evidence of the induction of apoptosis in both MKN-45 and AGS cell lines following PAEO treatment. The findings of this study offer evidence supporting the cytotoxic effects of PAEO on gastric cancer cell lines by promoting apoptosis. The findings suggest that PAEO may offer potential as a therapeutic candidate in managing and treating gastric cancer.

HS-SPME-GC-MS and Chemometrics for the Quality Control and Clustering of Monovarietal Extra Virgin Olive Oil: A 3-Year Study on Terpenes and Pentene Dimers of Italian Cultivars.

Terpenes and pentene dimers are less studied volatile organic compounds (VOCs) but are associated with specific features of extra virgin olive oils (EVOOs). This study aimed to analyze mono- and sesquiterpenes and pentene dimers of Italian monovarietal EVOOs over 3 years (14 cultivars, 225 samples). A head space-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method recently validated was used for terpene and pentene dimer quantitation. The quantitative data collected were used for both the characterization and clustering of the cultivars. Sesquiterpenes were the molecules that most characterized the different cultivars, ranging from 3.908 to 38.215 mg/kg; different groups of cultivars were characterized by different groups of sesquiterpenes. Pentene dimers (1.336 and 3.860 mg/kg) and monoterpenes (0.430 and 1.794 mg/kg) showed much lower contents and variability among cultivars. The application of Kruskal-Wallis test-PCA-LDA-HCA to the experimental data allowed defining 4 clusters of cultivars and building a predictive model to classify the samples (94.3% correct classification). The model was further tested on 33 EVOOs, correctly classifying 91% of them.

[Rapid determination of 15 N-nitrosamines in air-dried yak meat using one-step QuEChERS-gas chromatography-triple quadrupole mass spectrometry].

A method based on gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) coupled with one-step QuEChERS technique was developed for the simultaneous determination of 15 N-nitrosamines in air-dried yak meat. The hydration volume, extraction solvent, extracting salt, and cleaning material were optimized according to the characteristics of the N-nitrosamines and sample matrix. The optimized conditions were as follows: 10 mL of purified water for sample hydration, acetonitrile as the extraction solvent for the sample after hydration, 4.0 g of anhydrous MgSO4 and 1.0 g of NaCl as extracting salts, 500 mg of MgSO4+25 mg of C18+50 mg of PSA as cleaning materials. Favorable recoveries of the 15 N-nitrosamines were obtained when the extraction solution was incompletely dried. Thus, the final extract was dried to below 0.5 mL under a mild nitrogen stream and then redissolved to 0.5 mL with acetonitrile. After filtration, 200 µL of the sample was transferred to an autosampler vial for GC-MS/MS analysis. The 15 N-nitrosamines were determined using GC-MS/MS on a DB-HeavyWAX column (30 m×0.25 mm×0.25 µm) with an electron impact ion source in multiple-reaction monitoring (MRM) mode, and quantified using an external standard method. Under the optimized experimental conditions, the results showed that the calibration curves exhibited good linearities for the 15 N-nitrosamines, with correlation coefficients (r2) greater than 0.9990. The limits of detection (LODs) and the limits of quantification (LOQs) ranged from 0.05 to 0.20 µg/kg and from 0.10 to 0.50 µg/kg, respectively. At spiked levels of 1LOQ, 2LOQ, and 10LOQ, the average recoveries were 79.4%-102.1%, 80.6%-109.5%, and 83.0%-110.6%, respectively, and the relative standard deviations were in the range of 0.8%-16.0%. The low matrix effects of the 15 N-nitrosamines indicated the high sensitivity of the proposed method. The method was applied to detect representative commercial air-dried yak meat samples obtained using different processing techniques. Seven N-nitrosamines, including N-nitrosodimethylamine, N-nitrosodiisobutylamine, N-nitrosodibutylamine, N-methyl-N-phenylnitrous amide, N-ethyl-N-nitrosoaniline, N-nitrosopyrrolidine, and N-nitrosodiphenylamine were detected in all samples. The average contents of the seven N-nitrosamines was 0.08-20.18 µg/kg. The detection rates and average contents of the N-nitrosamines in cooked air-dried yak meat samples were higher than those in traditional raw air-dried yak meat samples. Compared with the manual QuEChERS method, the one-step QuEChERS method developed integrated the extraction and clean-up procedures into one single run, and the detection efficiency was considerably improved. The developed method is simple, rapid, highly sensitive, and insusceptible to human errors. Thus, it is useful for the determination of N-nitrosamines in air-dried yak meat and can be extended to the qualitative and quantitative analysis of N-nitrosamines in other meat products. It also provides method support and a data reference for the general determination of N-nitrosamines, which is of great significance for food safety.