JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2015
·
IF 3.564
Zhongping Huang,Peipei Zhang,Yang Sun,Yilei Huang,Zaifa Pan,Lili Wang
A novel method on basis of thin layer chromatography (TLC) combined with on-line pyrolytic methylation gas chromatography (OPM–GC) in the presence of trimethylsulfonium hydroxide (TMSH) was developed and applied to the determination of glyceride and free fatty acid residuals in biodiesel. Both glycerides and free fatty acids in biodiesel were separated by TLC alumina sheets, and then the cut spots were analyzed directly by pyrolytic methylation gas chromatography method in a pyrolyzer at 350 °C without complex pretreatment. In this process, glycerides and free fatty acids were converted into their corresponding fatty acid methyl esters, and quantified well by the total peak areas of formed esters. Thus obtained calibration curves of monostearin, distearin, tristearin and oleic acid exhibited good linearity with the regression coefficients from 0.9766 to 0.9950 at the concentrations ranged from 300 to 5000 mg L −1 . The limits of detection were in the range of 100–200 mg L −1 , and the RSDs ( n = 3) ranged from 3.7% to 12.5%, calculated for monostearin, distearin, tristearin and oleic acid at the concentration level of 2000 mg L −1 . The potential of the proposed method was assessed by the determination of glycerides and free fatty acids in real biodiesel samples. The results prove that this TLC–OPM–GC technique is a simple, accurate and low solvent consuming method for the simultaneous determination of glyceride and free fatty acid residuals in biodiesel.
研究领域:
分析化学
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环境科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Tiantian Zhang,Haonan Mi,Shichao Wei,Yuan Xu,Zhao Yang,Shuai Liang,Xuelu Ding
A novel, compact, and automated laser ablation dielectric barrier discharge thin layer chromatography-mass spectrometry (LA-DBD-TLC-MS) device was developed for the rapid detection of biogenic amines (BAs) in fishery products. This plug-and-play system integrates thermal desorption via diode laser, DBD plasma ionization, and tandem MS detection, with key operational parameters optimized through experimental and computational methods. Utilizing nanoscale carbon black as a matrix, the device achieved a detection limit of 0.230 pg/mm 2 . It demonstrated comparable efficacy to HPLC-MS/MS in screening six BAs and enabled species discrimination and spoilage assessment in fish with machine learning algorithms (PCA, RF, SVM, MLP), yielding high accuracies. A multi-linear regression model predicted salmon spoilage with a strong correlation (R 2 = 0.974). This study confirms the LA-DBD-TLC-MS device as a reliable, precise, and high throughput tool for rapid BA analysis in fishery products, with potential for direct trace analysis of organic compounds in food matrices.
研究领域:
食品科学
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分析化学
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人工智能
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2020
·
IF 3.594
Zhengdong Shen,Haiying Wang,Qian Yu,Qiang Li,Xiaomin Lu,Xianming Kong
The accumulated polycyclic aromatic hydrocarbons (PAHs) in edible oil can bring serious health concerns because of their carcinogenic features. PAHs could accumulate in edible oil from contaminated environment or food stuff. In this study, the combination uses of on-site thin layer chromatography and surface enhanced Raman scattering (SERS) spectroscopy has been successfully displayed to identify PAHs from edible oil samples. Diatomite which is a kind of porous biosilica was used to construct stationary phase on TLC plate, the photonic crystal feature of diatomite is beneficial for SERS enhancement. The highly-porous stationary phase composed of porous diatomite with void shell structure could promote mobile phase interaction with the stationary phase, which leading to improved mass transfer, uniformity and analyte resolution compare with the conventional silica gel plate. The edible oil (1 µL) was directly applied to the diatomite plate without pretreatment, and subjected to TLC separation. The polarity of target analytes was calculated for eluent optimization, on which four compounds of PAHs(benzo[a]pyrene, pyrene, anthracene and indeno[1,2,3-cd] pyrene) were successfully separated by using hexane/chloroform (15/1, v/v) as eluent, including compounds with similar polarity(benzo[a]pyrene 0.0477, indeno[1,2,3-cd] pyrene 0.6545, pyrene and anthracene are 0). 2 µL of Au colloid at 2.4 × 10 −7 M were transferred onto the diatomite plate for the SERS measurement. The limit of detection was found to be nearly at 1 ppm. The obtained results can easily identify the four compounds of PAHs in edible oil by their own characteristic Raman peaks. This proposed method provides a simple, instant and effective strategy for on-site identification PAHs from food samples.
研究领域:
食品安全
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分析化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
PHYTOCHEMICAL ANALYSIS
·
2024
·
IF 3
Yangling Li,Ying Su,Yongjuan Liang,Fangchan Li,Ning Lin,Lin Jiang,Qinghua Lin,Qing Chen
Introduction Kidney tea is an essential herbal medicine. It is widely used to treat conditions such as urinary stones, gallstones, and rheumatoid arthritis. There is currently no standardized or widely accepted research strategy for evaluating the quality of kidney tea granules (KTGs) after granulation. Objectives In this study, we aim to establish a comprehensive strategy for evaluating the quality of KTGs produced from different sources of kidney tea. Methods A TLC combined with HPLC method was established to identify the chemical components in KTGs, and HPLC method was used to determine the contents of rosmarinic acid of KTGs. In order to distinguish samples and identify differential components, similarity analysis, hierarchical cluster analysis (HCA), principal component analysis (PCA), and orthogonal partial least squares discriminant analysis (OPLS-DA) were conducted. Results TLC and HPLC detection confirmed three chemical components of KTGs, which are rosmarinic acid, caffeic acid, and lithospermic acid. HPLC fingerprint analysis revealed a total of seven common peaks in 15 batches of KTGs. Similarity analysis showed that the similarity of all 15 batches of KTGs was greater than 0.969. The peak areas of the seven common peaks were identified by chemical pattern recognition, and the results showed that most of the KTGs from different origins were clustered together, with small differences between them. The PCA and OPLS-DA results showed that two principal components can represent 82.638% of the common peaks of KTGs, among which peak 5 represents rosmarinic acid, which is the main differential biomarker of KTGs from different regions. Quantitative analysis of rosmarinic acid in KTG samples was performed using HPLC fingerprint conditions and the content of rosmarinic acid in 15 batches of KTGs samples was measured to be between 8.01–14.61 mg/g. Conclusion This study combines TLC, HPLC, and chemometrics to establish a stable and reliable method that can quickly and effectively identify the components of KTGs, accurately quantify known components in KTGs, and provide reference for the quality evaluation of KTGs.
研究领域:
中药学
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2014
·
IF 5.825
Zong-Mian Zhang,Jing-Fu Liu,Rui Liu,Jie-Fang Sun,Guo-Hua Wei
By coupling surface-enhanced Raman spectroscopy (SERS) with thin layer chromatography (TLC), a facile and powerful method was developed for on-site monitoring the process of chemical reactions. Samples were preseparated on a TLC plate following a common TLC procedure, and then determined by SERS after fabricating a large-area, uniform SERS substrate on the TLC plate by spraying gold nanoparticles (AuNPs). Reproducible and strong SERS signals were obtained with substrates prepared by spraying 42-nm AuNPs at a density of 5.54 × 1010 N/cm2 on the TLC plate. The capacity of this TLC-SERS method was evaluated by monitoring a typical Suzuki coupling reaction of phenylboronic acid and 2-bromopyridine as a model. Results showed that this proposed method is able to identify reaction product that is invisible to the naked eye, and distinguish the reactant 2-bromopyridine and product 2-phenylpyridine, which showed almost the same retention factors (Rf). Under the optimized conditions, the peak area of the characteristic Raman band (755 cm–1) of the product 2-phenylpyridine showed a good linear correlation with concentration in the range of 2–200 mg/L (R2 = 0.9741), the estimated detection limit (1 mg/L 2-phenylpyridine) is much lower than the concentration of the chemicals in the common organic synthesis reaction system, and the product yield determined by the proposed TLC-SERS method agreed very well with that by UPLC-MS/MS. In addition, a new byproduct in the reaction system was found and identified through continuous Raman detection from the point of sample to the solvent front. This facile TLC-SERS method is quick, easy to handle, low-cost, sensitive, and can be exploited in on-site monitoring the processes of chemical reactions, as well as environmental and biological processes.
研究领域:
分析化学
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材料科学
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化工
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环境科学
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生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2017
·Vol. 183
·期 4
·1488-1502
·
IF 1.751
Wang Liming,Chen Yan
Cycloastragenol (CA), an exclusive telomerase activator, was derived from the Astragali Radix which is widely distributed in Turkey. Until now, there is no report to produce CA with effective and environment-friendly methods. Biotransformation is considered to be a promising technology. Thus, the present study was aimed to establish a biotransformation technology that could efficiently produce CA. In this paper, a microorganism, LG-502, was used to successfully transform astragaloside IV (ASI) to CA by analysis of thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The phylogenetic analysis of the 16S rRNA indicated that this strain belongs to Bacillus sp. Three metabolites were separated during the fermentation and characterized to be cyclogaleginoside B, CA, and 20 R , 24 S -epoxy-6 α , 16 β , 25-trihydroxy-9, 19-cycloartan-3-one based on NMR and MS spectroscopic analyses. The conversion rate of ASI and yield rate of CA were achieved as high as 89 and 84%, respectively, under optimized conditions. Enzymatic analysis showed that the glycosidases were mainly located inside the bacterial body, and the activities of glucosidases were much higher than the xylosidases under the experimental conditions. This study provides a feasible, effective, and eco-friendly way to prepare CA from ASI, which might greatly contribute to the applications of ASI.
研究领域:
药学
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生物技术
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微生物学
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有机化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）