Simultaneous determination of three strong polarity herbicides in tea by ion chromatography-triple quadrupole mass spectrometry.

Due to lack of chromogenic groups and fluorescence groups, high boiling point, high polarity, low volatility, and small molecular weight of glyphosate, glufosinate and bentazone, the detection of three analyses were limited in all kinds of food. Herein, a method for the simultaneous determination of glyphosate, glufosinate and bentazone in tea by ion chromatography tandem triple quadrupole mass spectrometry (IC-MS) was developed, which is without organic solvent and complex derivatization. The recoveries of three compounds in different teas (black tea, green tea, white tea) ranged from 80.40 % to 107.00 %, and the intraday precision (n = 6) ranged from 0.57 % to 9.90 %, the daytime precision ranged from 1.00 % to 5.30 %, the quantitative limit (LOQ) ranged from 0.36 to 1.30 µg/L, and the detection limit (LOD) ranged from 0.11 to 0.39 µg/L. Furthermore, the detection limit and quantitative limit of glyphosate, glufosinate and bentazone by this method are lower than other methods in real samples. Meanwhile, the established method was successfully applied to determine the terminal residues of the three analytes in twelve tea samples from commercial market. Therefore, this method can provide reliable technical support for the study of residue status in vegetables and fruits.

[Determination of fluoroacetic acid in human blood and urine by accelerated solvent extraction-ion chromatography-mass spectrometry].

Fluoroacetic acid is a highly polar poison used for rodent control. When ingested by the human body, it seriously damages nerve cells and heart tissues and even causes death by cardiac arrest or respiratory failure. Common detection methods for fluoroacetic acid include gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, both of which require complex pretreatment methods, such as derivatization. In this study, a method to determine fluoroacetic acid in human blood and urine based on accelerated solvent extraction-ion chromatography-mass spectrometry (ASE-IC-MS) was established. Two pretreatment methods, namely, acetonitrile precipitation and accelerated solvent extraction, were compared. Furthermore, the effects of different extraction conditions, such as the extraction time, extraction temperature, and number of cycles, were investigated. The most suitable chromatographic separation conditions, such as the chromatographic column, column temperature, and elution procedure, were determined, and the MS conditions, such as the collision energy (CE) and declustering potential (DP) of the ion pairs of the target compound, were investigated. Based on the experimental results, the optimal pretreatment methods and detection conditions were obtained, and reliable data were collected. Deionized water was used as the extraction solvent, and blood and urine samples were processed by accelerated solvent extractor. The supernatant was sequentially collected via centrifugal ultrafiltration and 0.22 µm membrane filtration, diluted 50 times, and then injected into the chromatographic column for detection. An Ion Pac AS20 IC column was used for isocratic elution with 15.0 mmol/L KOH solution as the eluent. The effluent was passed through a suppressor and into a triple quadrupole mass spectrometer, which was used to perform MS/MS (ESI-) in multiple reaction monitoring (MRM) mode. The quantitative ion was m/z 77.0>57.0 when the CE and DP were -15.0 eV and -20.0 V, respectively. An external standard method was used for quantitative analysis. The results showed a good linear relationship for fluoroacetic acid in the range of 0.5-500.0 µg/L (r>0.999), with limits of detection (LOD) and quantification (LOQ) of 0.14 and 0.47 µg/L, respectively. The recoveries of fluoroacetic acid in blood and urine were 93.4%-95.8% and 96.2%-98.4%, respectively. The intra-day RSDs for blood and urine were 0.8%-1.6% and 0.2%-1.0%, respectively, while the inter-day RSDs were 2.3%-3.8% and 3.9%-6.9%, respectively. Further investigation revealed that the matrix effects of this method in blood and urine, at -7.4% and -3.0%, respectively, were fairly weak. The established method was successfully applied to detect fluoroacetic acid in human blood and urine obtained from a poisoning case, and the results obtained provided crucial clues that led to swift case resolution. The efficiency of the method was significantly higher than that of conventional detection methods. In conclusion, the developed method has high sensitivity and good repeatability and is suitable for the rapid detection of fluoroacetic acid in human blood and urine. Moreover, because this method does not require derivatization, it is simple and efficient.

Structural and temporal dynamics analysis on drug-eluting stents: History, research hotspots and emerging trends.

Purpose: This review aims to explore the history, research hotspots, and emerging trends of drug-eluting stents(DES)in the last two decades from the perspective of structural and temporal dynamics. Methods: Publications on DES were retrieved from WoSCC. The bibliometric tools including CiteSpace and HistCite were used to identify the historical features, the evolution of active topics, and emerging trends on the DES field. Results: In the last 20 years, the field of DES is still in the hot phase and there is a wide range of extensive scientific collaborations. In addition, active topics emerge in different periods, as evidenced by a total of 41 disciplines, 511 keywords, and 1377 papers with citation bursts. Keyword clustering anchored five emerging research subfields, namely #0 dual antiplatelet therapy, #3 drug-coated balloon, #4 bifurcation, 5# rotational atherectomy, and 6# quantitative flow ratio. The keyword alluvial map shows that the most persistent research concepts in this field are thrombosis, restenosis, etc., and the emerging keywords are paclitaxel eluting balloon, coated balloon, drug-eluting balloon, etc. There are 7 recent research subfields anchored by reference clustering, namely #2 dual antiplatelet therapy, #4 drug-coated balloon, #5 peripheral artery disease, #8 fractional flow reserve, #10 bioresorbable vascular scaffold, # 13 intravascular ultrasound, #14 biodegradable polymer. Conclusion: The findings based on the bibliometric studies provide the current status and trends in DES research and may help researchers to identify hot topics and explore new research directions in this field.

Effects of intracoronary low-dose prourokinase administration on ST-segment elevation in patients with myocardial infarction and a high thrombus burden: a randomized controlled trial.

OBJECTIVE: To evaluate the efficacy and safety of low-dose prourokinase (pro-UK) administration during primary percutaneous coronary intervention (PCI) for the treatment of acute ST-segment elevation myocardial infarction (STEMI) in patients with a high thrombus burden. METHODS: A prospective, randomized controlled trial was conducted at the Inner Mongolia People's Hospital, China. Patients with STEMI and a high thrombus burden who underwent thrombus aspiration and primary PCI were randomly allocated to pro-UK administration or control groups. The primary endpoint was corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC). RESULTS: There were no significant differences in the baseline demographics or clinical characteristics of the two groups. The CTFC, tissue myocardial perfusion grade, ST-segment resolution, and myocardial blush grade of the pro-UK group were significantly better than those of the control group. In addition, after 30 days of follow-up, the pro-UK group had better cardiac function and perfusion than the control group. There were no differences in the clinical outcomes or incidence of hemorrhage. CONCLUSIONS: Intracoronary low-dose pro-UK improves myocardial perfusion and cardiac function in patients with a high thrombus burden. Major hemorrhages still occur in patients administered pro-UK, but are no more frequent.Study registration: Chinese Clinical Trial Registry (ChiCTR1900022290).

Hedgehog-like Bi2S3 nanostructures: a novel composite soft template route to the synthesis and sensitive electrochemical immunoassay of the liver cancer biomarker.

An effective electrochemical immunosensor for detecting the liver cancer biomarker was developed based on the hedgehog-like Bi2S3 nanostructure, which was synthesized using novel CTAB-trimellitic acid as a composite soft template and thiourea as the sulfur source by a simple hydrothermal method with 20-fold sensitivity enhancement and one order of magnitude increase of linear range. The electrochemical immunosensor presented excellent performance, and could be applied to detect the cancer biomarker in clinical serum samples.

Facile synthesis of a nanorod-like MoS2 nanostructure for sensitive electrochemical biosensing application.

A novel nanorod-like MoS2 semiconductor nanostructure was synthesized through a simple two-step method. The nanorod-like MoS2 nanostructure was exploited as an electrode material to immobilize enzymes and for electrochemical sensing application. Characterization of the nanorod-like MoS2 nanostructure and the resultant biosensor was performed by scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Enzyme molecules loaded at the MoS2 nanostructure retained their native structure and bioactivity. The direct electron transfer of glucose oxidase at the MoS2 nanostructure coated glassy carbon electrode was enhanced greatly. At an optimal potential of -0.45 V, the electrochemical glucose sensor had wide linear ranges of 1.5 × 10-5-3.25 × 10-4 M and 3.25 × 10-4-1.43 × 10-3 M, and a low detection limit of 0.005 mM (S/N = 3) with a high sensitivity of 25.06 ± 0.5 mA M-1 cm-2. At the same time, the present biosensor showed excellent selectivity, reproducibility and stability for glucose. What's more, the biosensor was successfully applied to the determination of practical samples.

Synthesis of a manganese dioxide nanorod-anchored graphene oxide composite for highly sensitive electrochemical sensing of dopamine.

In this research, a novel manganese dioxide nanorod-anchored graphene oxide (MnO2 NRs/GO) composite was synthesized by a simple hydrothermal method for electrochemical sensing application. A highly sensitive electrochemical sensor for dopamine (DA) was constructed by modifying glassy carbon electrode (GCE) with MnO2 NRs/GO. The morphology and performance of the composite material and modified GCEs were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and cyclic voltammetry (CV), respectively. The resultant MnO2 NRs/GO composite has a large electroactive area and shows excellent electrochemical activity toward DA. Under the optimal conditions, the DA sensor shows a linear response in the DA concentration ranges of 0.1 µM-0.08 mM and 0.08-0.41 mM with a low detection limit of 0.027 µM and a high sensitivity of 602.4 µA·mM-1·cm-2. The MnO2 NRs/GO composite provides a promising platform for the construction of a highly sensitive and selective sensor of DA.

Perovskite-type calcium titanate nanoparticles as novel matrix for designing sensitive electrochemical biosensing.

In this work, novel perovskite-type calcium titanate nanoparticles (CaTiO3NPs) were for the first time exploited for the immobilization of proteins and the development of electrochemical biosensor. The CaTiO3NPs were synthesized with a simple and cost-effective route at low temperature, and characterized by scanning electron microscopy, X-ray photoelectron spectroscopic spectrum, electrochemical impedance spectrum, UV-visible spectroscopy, Fourier transform infrared spectrum, and cyclic voltammetry, respectively. The results indicated that CaTiO3NPs exhibited large surface area, and greatly promoted the direct electron transfer between enzyme molecules and electrode surface. The immobilized enzymes on this matrix retained its native bioactivity and exhibited a surface controlled, quasi-reversible two-proton and two-electron transfer reaction with an electron transfer rate of 3.35s-1. Using glucose oxidase as model, the prepared glucose biosensor showed a high sensitivity of 14.10±0.5mAM-1 cm-2, a wide linear range of 7.0×10-6 to 1.49×10-3M, and a low detection limit of 2.3×10-6M at signal-to-noise of 3. Moreover, the biosensor also possessed good reproducibility, excellent selectivity and acceptable storage life. This research provided a new-type and promising perovskite nanomaterials for the development of efficient biosensors.

A streptavidin functionalized graphene oxide/Au nanoparticles composite for the construction of sensitive chemiluminescent immunosensor.

In this work, a novel streptavidin functionalized graphene oxide/Au nanoparticles (streptavidin/GO/AuNPs) composite is prepared and for the first time used to construct sensitive chemiluminescent immunosensor for the detection of tumor marker. The streptavidin/GO/AuNPs composite and the immunosensor are characterized using scanning electron microscopy, static water contact angle measurement and electrochemical impedance spectroscopy. The biofunctionalized composite has large reactive surface area and excellent biocompatibility, thus the capture antibody can be efficiently immobilized on its surface based on the highly selective recognition of streptavidin to biotinylated antibody. Using α-fetoprotein (AFP) as a model, the proposed chemiluminescent immunosensor shows a wide linear range from 0.001 to 0.1 ng mL(-1) with an extremely low detection limit down to 0.61 pg mL(-1). The resulting AFP immunosensor shows high detection sensitivity, fast assay speed, acceptable detection and fabrication reproducibility, good specificity and stability. The assay results of serum samples with the proposed method are in an acceptable agreement with the reference values. This work provides a promising biofunctionalized nanostructure for sensitive biosensing applications.