查找使用阿拉丁产品的科研文献

Ratiometric fluorescence detection of tetramethylpyrazine in complex matrices using a Tb-EDTA probe based on LMCT modulation

Haiyan Cao,Bin Yang,Wenfei Dong,Wenbing Shi

Background The accurate detection of 2,3,5,6-tetramethylpyrazine (TMP) in complex matrices is significant for food quality control and biomedical analysis. Despite this need, a dedicated optical sensing platform for TMP has not been reported to date. Results Here, we present a novel ratiometric fluorescent probe based on a Tb–EDTA complex, which introduces a sensing strategy founded on coordination-induced modulation of the ligand-to-metal charge transfer (LMCT) process. Specific coordination of TMP's pyrazine nitrogen atoms to the Tb 3+ center results in a characteristic ratiometric response: quenching of the emission at 548 nm and concomitant enhancement at 650 nm. The probe exhibits excellent analytical performance with a linear range of 0.1―40 μM, a detection limit of 0.038 μM, and high selectivity over structurally similar interferents. Its practical applicability is demonstrated by reliable quantification of TMP in real samples, including sauce-flavor Baijiu, sake, and human urine, with recoveries of 94.54–104.82% and relative standard deviations below 10.57%. Significance This work establishes a pioneering optical sensing approach for TMP detection, providing a valuable analytical tool for flavor assessment in alcoholic beverages and pharmacological monitoring in biological systems.

From isostructural to hetero-structural one-dimensional coordination polymers adjusted by changing the ligand substituent group from pyrazine to furan

LI-Juan Zhao,Meng-Ru Yin,Guo-Ping Yong

Comparison of pyrazines formation in methionine/glucose and corresponding Amadori rearrangement product model

Shibin Deng,Heping Cui,Khizar Hayat,Yun Zhai,Qiang Zhang,Xiaoming Zhang,Chi-Tang Ho

The generation of pyrazines in a binary methionine/glucose (Met/Glc) mixture and corresponding methionine/glucose-derived Amadori rearrangement product (MG-ARP) was studied. Quantitative analyses of pyrazines and methional revealed that MG-ARP generated more methional compared to Met/Glc, whereas lower content and fewer species of pyrazines were observed in the MG-ARP model. Comparing the availability of α -dicarbonyl compounds generated from the Met/Glc model, methylglyoxal (MGO) was a considerably effective α -dicarbonyl compound for the formation of pyrazines during MG-ARP degradation, but glyoxal (GO) produced from MG-ARP did not effectively participate in the corresponding formation of pyrazines due to the asynchrony on the formation of GO and recovered Met. Diacetyl (DA) content was not high enough to form corresponding pyrazines in the MG-ARP model. The insufficient interaction of precursors and rapid drops in pH limited the formation of pyrazines during MG-ARP degradation. Increasing reaction temperature could reduce the negative inhibitory effect by promoting the content of precursors.

Characterization of the Key Aroma-Active Compounds in Yongchuan Douchi (Fermented Soybean) by Application of the Sensomics Approach

Shuqi Wang,Yuan Chang,Bing Liu,Haitao Chen,Baoguo Sun,Ning Zhang

Yongchuan douchi is a traditional fermented soya bean product which is popular in Chinese dishes due to its unique flavor. In this study, the key aroma-active compounds of Yongchuan douchi were characterized by the combined gas chromatography–olfactometry (GC–O) and gas chromatography−mass spectrometry (GC–MS) with sensory evaluation. In total, 49 aroma compounds were sniffed and identified, and 20 of them with high flavor dilution factors (FD) and odor activity values (OAVs) greater than one were screened by applied aroma extract dilution analysis (AEDA) and quantitated analysis. Finally, aroma recombination and omission experiments were performed and 10 aroma-active compounds were thought to have contributed significantly including 2,3-butanedione (butter, cheese), dimethyl trisulfide (garlic-like), acetic acid (pungent sour), acetylpyrazine (popcorn-like), 3-methylvaleric acid (sweaty), 4-methylvaleric acid (sweaty), 2-mehoxyphenol (smoky), maltol (caramel), γ-nonanolactone (coconut-like), eugenol (woody) and phenylacetic acid (flora). In addition, sensory evaluation showed that the flavor profile of Yongchuan douchi mainly consisted of sauce-like, sour, nutty, smoky, caramel and fruity notes.Keywords:douchi;aroma-active compounds;AEDA;OAV;GC–MS;GC–O

Molecularly imprinted electrochemical sensor to sensitively detect tetramethylpyrazine in Baijiu

Yating Rui,Jianfeng Wu,Qunyong Tang,Juan Pu,Wanpeng Wang,Shou-Nian Ding

Tetramethylpyrazine (TMP) is a compound known for its natural health benefits, but current detection methods for TMP are overly expensive and time-consuming. In this study, we developed functional materials with TMP molecular recognition properties using molecularly imprinted technology. As TMP does not produce electrochemical signals in the detection potential range, hexacyanoferrate was selected as a redox probe, combined with the highly conductive polymer PEDOT:PSS to enhance electrode conductivity. When coupled with the TMP-specific functional materials prepared through molecular imprinting, an electrochemical sensor specifically recognizing TMP was successfully developed, and this was confirmed through characterization techniques such as ultraviolet spectroscopy and scanning electron microscopy. Additionally, the crucial experimental parameters were optimized for improved performance. Under optimal conditions, the use of differential pulse voltammetry (DPV) to measure the peak currents of hexacyanoferrate showed a linear relationship with TMP concentrations from 0.50 × 10−6 to 5.00 × 10−3 M, achieving a detection limit of 2.1 × 10−7 M. This method proved effective for quantifying TMP in Baijiu samples, demonstrating good precision with relative standard deviations (RSD) ranging from 2.71% to 3.28%, and recovery percentages between 95.77% and 101.88%. These results indicate the potential of the molecularly imprinted polymer (MIP) sensor for accurately measuring TMP in actual samples.