查找使用阿拉丁产品的科研文献

Combined use of analyte protectants and precolumn backflushing for a robust, high-throughput quantitative determination of aroma compounds in cigarette mainstream smoke by gas chromatography-tandem mass spectrometry

Qiong Guo,Lining Pan,Yaqiong Qin,Fuwei Xie,Xiaoyu Wang,Xiaodong Zhao,Li Chen,Bing Wang,Junlan Cai,Huimin Liu

Trace analysis of multi-targets in complex matrices such as cigarette smoke has always been a great challenge for analysts. In this paper, a high-throughput qualitative and quantitative method was developed and validated to determine 559 aroma compounds in mainstream smoke using gas chromatography-tandem mass spectrometry. Among four commonly used extraction solvents, dichloromethane showed obvious advantages in extracting the target aroma compounds with different polarity. An analyte protectant mixture consisting of 3-methoxy-1,2-propanediol, 1,2-octandiol, 1,2-nonanediol, and 1,2-tetradecanediol was first presented to compensate for the matrix effect, which was suitable for solvents of a wide polarity range such as hexane, dichloromethane, acetone, acetonitrile, and methanol. Moreover, the introduction of precolumn backflushing markedly improved the instrument robustness in analyzing complex cigarette smoke. The results showed that the system retained good stability after 30 days of injection. The proposed method performed well in terms of key validation parameters: accuracy (70.3–118.8% for 552 compounds), inter/intraday precision (0.1–10.7% and 0.2–18.2%), and sensitivity (limit of detection 0.12–102.54 ng/mL). Finally, this method was successfully applied to analyze 12 different commercial cigarette brands. The proposed method has good application prospects based on its robustness and may be used as a potential tool to transfer the cigarette design from an experience-dependent mode to a digital design mode. This method also shows potential in assaying aroma compounds in essentials, food or plant-based substrates.

Predictive metabolic signatures for the occurrence and development of diabetic nephropathy and the intervention of Ginkgo biloba leaves extract based on gas or liquid chromatography with mass spectrometry

Yan Du,Bing-ju Xu,Xu Deng,Xiao-wen Wu,Yin-jie Li,Shi-rui Wang,Yi-nan Wang,Shuai Ji,Meng-zhe Guo,Dong-zhi Yang,Dao-quan Tang

Diabetic nephropathy (DN) is one of the leading causes of death in diabetes mellitus (DM). Early warning and therapy has significant clinical value for DN. This research sought to find biomarkers to predict the occurrence and development of DN and the intervention of Ginkgo biloba leaves extract (GBE) by quantifying fatty acids, amino acids, and nucleosides and nucleobases in rat plasma. Samples were respectively collected at the weekend of 5–10 weeks after diabetic rats induced by streptozotocin were defined. Plasma fasting blood-glucose, kidney index, blood urea nitrogen, creatinine, urine albumin excretion and ultrastructural morphology of kidney were measured or observed. Fatty acids, amino acids and nucleosides and nucleobases in rat plasma were analyzed by gas chromatography or liquid phase chromatography and mass spectrometry, respectively. From the biochemical index and morphological change of kidney, the rats from the 5th to 7th week were in the stage of DM while from the begin of 8th week the rats were suggested in the early stage of DN. The results of quantitative metabolomics showed that 16 differential metabolites were related to the progression of DN, and oleic acid, glutamate and guanosine might be the potential biomarkers of kidney injury. 14 differential metabolites were related to GBE against the progression of DN, while oleic acid and glutamate might be the potential biomarkers of GBE against kidney injury. Those findings potentially promote the understanding of the pathogenic progression of DN and reveal the therapeutic mechanism of GBE against DN.

Preparation of phenothiazine bonded silica gel as sorbents of solid phase extraction and their application for determination of nitrobenzene compounds in environmental water by gas chromatography–mass spectrometry

Xi-Tian Peng,Xing Zhao,Yu-Qi Feng

In this paper, two phenothiazine bonded silica (PTZ-Si) sorbents were prepared and used as sorbents of solid-phase extraction (SPE) for the determination of nitrobenzene compounds in environmental water samples by gas chromatography–mass spectrometry (GC–MS). Different synthesis routes were proposed to obtain high bonded amount of PTZ on the surface of silica gel . PTZ molecule was derived to its amino or acyl chloride derivatives for reacting with isocyanate or amino silane coupling agent, which was further reacted with the surface silanol groups of silica gel to obtain the PTZ-Si sorbents. The resultant PTZ-Si sorbents were characterized by nitrogen sorption porosimetry (NSP), Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (EA) to assure the successful bonding of PTZ on the surface of silica gel. Then the PTZ-Si sorbents were served as SPE sorbents for the enrichment of nitrobenzene compounds. Several parameters affecting the extraction performance were investigated. Under the optimized conditions, the proposed method was applied to the analysis of six nitrobenzene compounds in environmental water samples. Good linearities were obtained for all nitrobenzene compounds with R 2 larger than 0.9958. The limits of detection were found to be in the range of 0.06–0.3   ng/mL. The method recoveries of nitrobenzene compounds spiked in water samples were from 71.4% to 124.3%, with relative standard deviations (RSDs) less than 10.1%.

Space-confined growth of lead-free halide perovskite Cs3Bi2Br9 in MCM-41 molecular sieve as an efficient photocatalyst for CO2 reduction at the gas−solid condition under visible light

Zihao Cui,Peng Wang,Yaqiang Wu,Xiaolei Liu,Guoqiang Chen,Peng Gao,Qianqian Zhang,Zeyan Wang,Zhaoke Zheng,Hefeng Cheng,Yuanyuan Liu,Ying Dai,Baibiao Huang

A facile and effective impregnation method is employed to synthesize the space-confined growth of lead-free halide perovskite Cs 3 Bi 2 Br 9 in MCM-41 molecular sieve. This MCM-41 @CBB (Cs 3 Bi 2 Br 9 ) composite shows an outstanding performance for the photocatalytic reduction of CO 2 to CO at the gas−solid condition under visible-light irradiation. The CO production rate of the MCM-41 @ 50 wt% CBB is determined to be 17.24 μmol g −1 h −1 , which greatly exceeds that of pure CBB (1.89 μmol g −1 h −1 ). The composite is highly stable showing no apparent decrease in the catalytic activity after 8 cycles of repeated experiment. The performance of space-confined growth of CBB nanoparticles in the serial molecular sieve exhibits 2.97–13.4 fold higher than that of pure CBB, respectively, which is superb than CPB (CsPbBr 3 ) and MCM-41 @CPB prepared in the same condition. The results are comparable with those reported for many lead halide perovskites, and are in the top among the lead-free perovskites, especially bismuth halide perovskites.

Headspace solid-phase microextraction and on-fiber derivatization for the determination of 3-/2-MCPDE and GE in breast milk and infant formula by gas chromatography tandem mass spectrometry

Shihuan Li,Jinhui Li,Senwei Feng,Linlin Bian,Zhuoting Liu,Yunfang Ping,Xu Wang,Ann Van Schepdael

The presence of fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPDE), 2-monochloropropane-1,3-diol (2-MCPDE) and glycidyl (GE) in foods is a potential concern due to their toxicity, especially for infants. This study proposed a rapid, sensitive and environmentally friendly method for simultaneous determination of the 3-/2-MCPDE and GE in breast milk and infant formula using headspace solid-phase microextraction (SPME) and on-fiber derivatization combined with gas chromatography-tandem mass spectrometry (GC-MS/MS). The approach proved high sensitivity with detection limits of 0.10 μg/L and 0.15 μg/kg for MCPDEs in breast milk and infant formula, respectively. Mean recoveries were obtained ranging from 79.9 to 111.2% for breast milk and from 82.1 to 106.7% for infant formula, with relative standard deviation (RSD) of less than 9.5%. According to the levels of 3-MCPDE and GE determined in 30 breast milk and 23 infant formulas, the exposure to 3-MCPDE and GE may pose a potential health risk for infants from birth to <12 months fed by breast milk and infants from birth to 6 months fed by infant formula.

Ag/APTES/CuxO (x = 1, 2)-MGS-Coated No-Core Fiber Surface Plasmon Resonance Gas Sensor and Its Application in Hydrogen Sulfide Detection

Cheng Li,Liu Xiao,Xiaozhan Yang,Wenlin Feng

Eco-friendly miniaturized kapok-fiber supported liquid-phase extraction coupled with gas chromatography-flame ionization detector for high-throughput edible oil preparation and low-cost determination of synthetic antioxidants

Yongyue Chen,Wenxuan Li,Yuwei Liu,Yifeng Lou,Jiaqi Chen,Xia Xu,Xuezhong Shi,Lei Ma,Yongli Yang,Di Chen

The addition of synthetic phenolic antioxidants can effectively delay or prevent oxidation of edible oils . However, excessive use of these antioxidants can have negative impacts, which emphasizes the importance of accurate analysis methods to determine their presence in edible oils. Given the large number of food samples involved in regulatory purposes, there is a need to develop high-throughput and cost-effective detection methods for routine analysis. However, the existing methods are not suitable, indicating a need for further improvement. This study presents a technique that combines miniaturized-kapok fiber-supported liquid-phase extraction (mini-KF-SLE) with gas chromatography-flame ionization detection (GC-FID) to determine synthetic antioxidants like 3- tert -butyl-4-hydroxyanisole, 3,5-di- tert -butyl-4-hydroxytoluene, and tert -butylhydroquinone in edible oils. The mini-KF-SLE device consists of 20 mg of kapok fibers placed in a 1 mL pipette tip attached to a pipette. The extraction procedure involves three simple steps: loading the oil sample (150 mg), adding the extractant (150 µL of ACN), and eluting the extractant by applying air pressure using a pipette. The developed mini-KF-SLE-GC-FID method shows satisfactory quantitation ability (R 2 >0.99) and detection limits of 0.4–0.5 µg/g. Moreover, the relative standard deviations for all analytes were below 9.2%, indicating good precise of the method for routine analysis. The proposed method also exhibits excellent environmental friendliness , as evidenced by three widely recognized metrics. Overall, the mini-KF-SLE-GC-FID method provides a convenient, low-cost, environmentally friendly, and easy to automate alternative for routinely determining synthetic antioxidants in edible oils.

Decoding the evolution of aromatic volatile compounds and key odorants in Suancai (a Chinese traditional fermented vegetable) during fermentation using stir bar sorptive extraction–gas chromatography–olfactometry–mass spectrometry

Yuan Mei,Lihong Ge,Haimei Lai,Yali Wang,Xueqing Zeng,Yuli Huang,Menglu Yang,Yongqing Zhu,Huajia Li,Juan Li,Chuanchuan Guo,Tao Hu,Nan Zhao

This study aimed to reveal the evolution of volatile compounds and key odorants in Suancai during two-stage fermentation using stir bar sorptive extraction–gas chromatography–olfactometry–mass spectrometry (SBSE–GC–O/MS). In total, 138 volatile compounds were identified, and 53 aroma-active compounds were detected. The ester composition and alkane and alcohol contents were different in fresh leaf mustard and Suancai in various fermentation stages. During pre-salting, the aroma profile transformed from pungent to salty as the isothiocyanate level decreased. During secondary fermentation, isothiocyanate levels were further reduced, and esters and alcohols with mild aroma were produced, causing the rich and mild aroma of Suancai. Based on the reduced isothiocyanate content and transformed aroma, isothiocyanate may be a key marker for estimating the maturity degree of Suancai. This study provides a theoretical basis for improving the aromatic quality of fermented vegetables.

Combining gas chromatography-ion mobility spectrometry and olfactory analysis to reveal the effect of filled-N2 anaerobic treatment duration on variation in the volatile profiles of gabaron green tea

Dongzhu Huang,Mengru Li,Hong Wang,Maoyin Fu,Shaode Hu,Xiaochun Wan,Zhuochen Wang,Qi Chen

Gamma-aminobutyric acid green tea (GAGT) is a tea with health benefits by a special anaerobic process to increase the GABA content. However, the effect of this special processing on tea flavor during processing has been rarely reported. In this study, GC-IMS was combined with principal component analysis (PCA) to clarify the effects of different times of anaerobic treatment on the volatile profiles in finished GAGT. GC-O-MS and quantitative descriptive analysis (QDA) were used to investigate the flavor characteristics of GAGT infusion. The results showed that the aroma abundance of GAGT peaked at about 8 h after anaerobic treatment, and then the GAGT flavor delayed. At this point, the differential compounds including nonanal, octanal, heptanal and linalool could be perceived by panalists. Other compounds that didn't change very much in content during processing but had high FD factors, such as β -damascenone, ( E )- β -ionone, 1-octen-3-ol and 1-octen-3-one, were also screened as odor-active compounds. Together, they constitute the characteristic flavors of “sweet”, “ketchup” and “slightly fermented” of GAGT infusion. This study will help to better understand the mechanism of GAGT aroma generation and improve the processing.

Comparative analysis of the liver-protective effects of raw and stir-fried semen of Hovenia dulcis in rats via gas chromatography–mass spectrometry–based serum metabolomic profiling and chemometrics

Pan Lv,Fei Zhu,Meiyan Lv,Jiaqi Bao,Linying Lv,Xiangwei Xu,Yi Tao

In this study, we used a serum metabolomics methodology based on GC coupled with MS (GC–MS) to investigate the liver-protective effects of raw and stir-fried semen of Hovenia dulcis in rats models of carbon tetrachloride–induced liver injury. Multivariate statistical analysis, such as principal component analysis and orthogonal partial least squares discriminant analysis, were performed to examine changes in the metabolic state of rats with carbon tetrachloride–induced liver injury, as well as the recovery pattern of rats pretreated with the raw and stir-fried semen of H. dulcis . Liver tissues were subjected to histopathological examination. A total of 47 biomarkers were predicted to contribute to the dynamic pathological processes in the liver injury, such as phenylalanine, glutamic acid, glycine, arachidonic acid and linoleic acid. Further analysis revealed that pathways associated with phenylalanine, tyrosine and tryptophan biosynthesis, and linoleic acid metabolism were altered in the injured liver, and that pretreatment with raw and stir-fried semen of H. dulcis abolished the changes in the aforementioned metabolic pathways.

A solid phase microextraction Arrow with zirconium metal–organic framework/molybdenum disulfide coating coupled with gas chromatography–mass spectrometer for the determination of polycyclic aromatic hydrocarbons in fish samples

Yongli Yuan,Xiaoting Lin,Tianhua Li,Tianyu Pang,Youren Dong,Rongjie Zhuo,Qiqin Wang,Yuting Cao,Ning Gan

Solid phase microextraction (SPME) Arrows with enlarged sorption phases and Arrow-shaped tips are good alternatives to classic SPME fibers. Developing SPME Arrows with functionalized coatings has become a growing area of SPME research. In this study, a zirconium metal organic framework/molybdenum disulfide (UiO-66/MoS 2 ) composite coating modified SPME Arrow was developed and coupled with gas chromatography-mass spectrometry for the headspace extraction and detection of 16 polycyclic aromatic hydrocarbons (PAHs). The coating preparation can be easily manipulated by the assembly strategy using silicone gels to adhere UiO-66/MoS 2 powder onto the surface of the Arrows. The prepared UiO-66/MoS 2 coated SPME Arrows exhibited clearly enhanced adsorption capacity (2.1–4.5 folds) and an improved degree of affinity to PAHs species when compared to commercial PDMS/CARS/DVB SPME Arrows or fibers. The improved mechanism may be due to the high specific area, hierarchical micropores and mesopores, and the largely increased and immobilized amount of UiO-66/MoS 2 coating on the stainless-steel Arrow. Under optimized conditions, the SPME Arrow-based assay was successfully applied to determine PAH levels in fish samples with satisfactory recoveries of 80.2–101% and relative standard deviations (RSDs) of less than 6%. The detection limits of PAHs were between 0.11–1.40 ng kg −1 . The coating showed satisfied reproducibility and repeatability (RSD <8.6%) with only 10 mL of 10% (v/v) acetone in water used as the extraction phase in an effort to be environmentally friendly. All of the results showed that the method is simple, sensitive, and robust. SPME Arrows with UiO-66/MoS 2 coatings can provide new opportunities for the efficient extraction of persistent organic pollutants in food safety applications.

An eco-friendly system of thermally regenerative battery-driven electrochemical CO2 reduction: In-situ harvesting of low-grade heat as electrical power for reducing CO2 emissions of flue gas

Si Li,Zhenchong Xiao,Yu Shi,Liang Zhang,Jun Li,Qian Fu,Xun Zhu,Qiang Liao

To realize the utilization of power energy from thermally regenerative batteries and treat flue gas, an eco-friendly coupled system of thermally regenerative battery-driven electrochemical reduction of carbon dioxide is proposed. This system recovers low-grade waste heat for electrical power while in-situ utilization for carbon dioxide reduction. The results show that carbon nanotubes-loaded silver catalyst enhances electrochemical carbon dioxide reduction performance due to increased active sites exposure. Output voltage and maximum power correlate linearly with the number of cell pairs in the thermally regenerative battery stack. Operating with 4 cell pairs, the eco-friendly coupled system achieves an average carbon monoxide Faradaic efficiency of 76.6 % and an average carbon monoxide Faradaic current density of 5.4 mA cm −2 . A minimum of 3 cell pairs is necessary for system operation. The increase of cell pairs in a certain range is beneficial for the performance improvement of electrochemical reduction of carbon dioxide. The eco-friendly coupled system attains an average Faradaic efficiency of 89.4 % and an average carbon monoxide Faradaic current density of 17.8 mA cm −2 with 8 cell pairs. This coupled system indicates a feasible and promising way to simultaneously reduce the emission of low-grade waste heat and carbon dioxide in flue gas without additional inputs.