摘要：
A highly sensitive Surface Plasmon Resonance (SPR) sensor coupled magnetic molecularly imprinted polymers nanoparticles (MMIPs NPs) was developed and validated for the determination of 6-benzylaminopurine (6-BA) in vegetables. MMIPs NPs were synthesized using methacrylic acid (MAA) and sodium p-styrene sulfonate (SSS) as functional monomers. The SPR exhibited a linear dependence on 6-BA concentration in the range 5-300pg/mL with a low limit of detection (3.02pg/mL) and limit of quantitation (10.08pg/mL). The SPR signal of 6-BA-captured MAA/SSS-MMIPs NPs is higher than those of the structural analogues (6-KT and 2-IP: 1.72 and 2.12 times) and the non-structural analogues (2, 4-D and NAA: 2.31 and 2.57 times), indicating the SPR sensor has good selectivity for 6-BA. The recovery of the established method was between 93.8% and 108.6% with a coefficient of variation less than 9.2% in four vegetables. This SPR sensor shows great potential in detecting 6-BA in more vegetables.
通讯机构：
[Xia Liu] H;Hunan Provincial Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
<jats:p>Long-term use of norfloxacin (NOR) will cause NOR residues in foods and harm human bodies. The determination of NOR residues is important for guaranteeing food safety. In this study, a simple, selective, and label-free colorimetric chemosensor for in situ NOR detection was developed based on Fe3O4 magnetic molecularly imprinted nanoparticles (Fe3O4 MMIP NPs). The Fe3O4 MMIP NPs showed good peroxidase-like catalytic activity to 3,3′,5,5′-tetramethylbenzidine (TMB) and selective adsorption ability to NOR. The colorimetric chemosensor was constructed based on the Fe3O4 MMIP NPs-H2O2-TMB reaction system. The absorbance differences were proportional to the concentrations of NOR in the range of 10–300 ng/mL with a limit of detection at 9 ng/mL. The colorimetric chemosensor was successfully applied to detect NOR residue in milk. The recovery range was 78.2–95.81%, with a relative standard deviation of 2.1–9.88%. Together, the proposed colorimetric chemosensor provides a reliable strategy for the detection of NOR residues in foods.</jats:p>
摘要：
<jats:title>Abstract</jats:title><jats:p>This study evaluated the interaction of <jats:italic>Chrysanthemum indicum</jats:italic> (CI) flavonoids (luteolin, acacetin, and buddleoside) with α‐amylase. Surface plasmon resonance (SPR) assay showed their equilibrium dissociation constants (<jats:italic>K<jats:sub>D</jats:sub></jats:italic>) are 1.9695±0.12, 2.9240±0.20, and 3.2966±0.08mM at pH 6.0, respectively. Furthermore, their binding affinities were influenced by KCl, MgCl<jats:sub>2</jats:sub>, and CaCl<jats:sub>2</jats:sub>. Enzymatic kinetic studies revealed that three flavonoids exhibited noncompetitive α‐amylase inhibitory activity. The inhibitory sequence is luteolin>acacetin>buddleoside, which was in accordance with the results of binding affinity from SPR. 1,1‐diphenyl‐2‐picryl hydrazyl radical assay demonstrated that antioxidant activities of three flavonoids were inhibited significantly with α‐amylase. Meanwhile, the study reveals that hydroxyl on C′‐4, C′‐5, and C‐7 of flavonoids play an important role on the interaction of three flavonoids with α‐amylase. Also, SPR could be used as sensor for rapid screening inhibitors of α‐amylase and provide useful information for the application of <jats:italic>C.indicum</jats:italic> flavonoids in food and pharmaceutical area.</jats:p>
摘要：
A method is reported for in-situ detection of the antibiotic tetracycline (TC). It is based on a combination of extraction of TC by magnetic molecularly imprinted polymers nanoparticles (MMIPs NPs) and detection by surface plasmon resonance (SPR). The TC-captured MMIPs NPs were flowed over the surface of the SPR chip that was modified with mercaptoethylamine. The SPR signal undergoes a strong increase through the use of MMIPs NPs. It increases linearly in the 5.0-100 pg center dot mL(-1) TC concentration range, and the detection limit is as low as 1.0 pg center dot mL(-1) (at S/N = 3). This method shows selectivity to TC compared with structurally analogues. In order to demonstrate the power of the method, it was applied to the analysis of milk spiked with TC. These results were validated by comparing them to those of an enzyme-linked immunoassay. The average recovery is in the range of 95.7-104.6%. Graphical abstract Schematic representation of a surface plasmon resonance assay for the sensitive determination of tetracycline in milk using the magnetic molecularly imprinted polymers nanoparticles that can extract tetracycline and amplify the SPR signal.
摘要：
An adulteration of high-price oil has been an important concern in agri-food fraud problems. Triacylglycerols are the main components of edible plant oils, which play an important role as target for adulteration detections. The objective is to evaluate the utility of triacylglycerol profiles in the detection of adulteration in high priced oils. An effective method is established to detect adulteration of high priced oils based on triacylglycerol profiles and chemometrics. Triacylglycerol profiles of edible oils are analyzed by an APCI-MS3-IT-MS. All triacylglycerol compounds are quantified by normalization of the chromatographic peak area in selected reaction monitoring (SRM) mode based on MS3 fragment ion pairs, which are used to eliminate interference from the isobaric species of triacylglycerol. The results of the hierarchical cluster analysis (HCA) and random forest (RF) classification algorithm indicated that peanut, soybean, sesame, sunflower seed, and linseed oils are completely classified into five groups based on their triacylglycerol profiles. Finally, a recursive support vector machine (R-SVM) discriminant model is established, which can successfully identify adulteration of high priced oil with cheaper edible oils at a concentration of as low as 4% with an accuracy of 93.7%. Practical Applications: The triacylglycerol profiles of edible plant oils are analyzed by RPLC-APCI-IT-MS. The SRM scan mode based on MS3 fragment ion pairs can eliminate interference of triacylglycerol isomers. The discriminant model for adulterated high-price oils is established by R-SVM. HCA, and RF can classify the five kinds of edible plant oil. The triacylglycerol of five edible plant oils is analyzed by RPLC-APCI-MS3-IT-MS. The triacylglycerol data matrix is submitted using unsupervised (HCA) and supervised (RF) chemometric methods to classify five kinds of edible plant oil. A discriminant model established with the R-SVM can be used to identify adulterated linseed oil samples (>= 4%) with an accuracy of 93.7%.
摘要：
A novel lysosome-targetable phthalimide fluorescent probe was designed for detecting palladium based on ESIPT for signal transduction. The fluorescent probe conjugating with allylcarbamate displayed weak fluorescent due to the ESIPT process hinder by allylcarbamate. But with the addition of palladium, the ESIPT emission was recovery though the palladium-catalyzed deallylation reaction and the fluorescence intensity exhibited 40-fold enhancement at 511 nm. In addition, the probe showed excellent selectivity, high sensitivity, fast responds and low limit detection for palladium with a larger Stoke-shift. Moreover, the targetable probe was also successfully applied for detecting palladium in lysosomes of living cells. Hence, the probe though ESIPT modulation is a promising for monitoring palladium in practical samples. (C) 2018 Published by Elsevier B.V.
摘要：
This study evaluated the interaction of Chysanthremum indicum flavonoids(luteolin,acacetin and buddleoside)with starch by surface plasmon resonance(SPR).Their equilibrium dissociation constant(KD)were(4.822 4依0.06),(3.441 3依0.06)and(2.367 6依0.25)mmol/L,respectively.On this basis,it was found that three flavonoids had inhibitory effect on the digestion of starch.when the concentration was 100滋mol/L,the inhibition rate was 10.92%,16.02%and 26.71%,respectively.Moreover,the antioxidant activity of Chysanthremum indicum flavonoids was inhibited after the interaction with starch.The results showed that the number and position of hydroxyl groups played an important role in the interaction between the three flavonoids and starch.In addition,SPR can be used as a rapid method to study the interaction of flavonoids and starch,and provide useful information for the application of Chrysanthemum indicum flavonoids in food and pharmaceutical area.
