Carbon and Tin-Based Polyacrylonitrile Hybrid Architecture Solid Phase Microextraction Fiber for the Detection and Quantification of Antibiotic Compounds in Aqueous Environmental Systems

In this study, the detection and quantification of multiple classes of antibiotics in water matrices are proposed using a lab-made solid phase microextraction (SPME) fiber coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The lab-made fiber was prepared using a graphene oxide (G), carbon nanotubes (C), and tin dioxide (T) composite, namely GCT, with polyacrylonitrile (PAN) as supporting material. The detected antibiotics were enrofloxacin, sulfathiazole, erythromycin, and trimethoprim. The custom-made fiber was found to be superior compared with a commercial C18 fiber. The excellent reproducibility and lower intra-fiber relative standard deviations (RSDs 1.8% to 6.8%) and inter-fiber RSDs (4.5% to 8.8%) made it an ideal candidate for the detection of traces of antibiotics in real environmental samples. The proposed validated method provides a satisfactory limit of detection and good linear ranges with higher (>0.99) coefficient of determination in the aqueous system. Application of the method was made in different real water systems such as river, pond and tap water using the standard spiking method. Excellent sensitivity, reproducibility, lower amount of sample detection and higher recovery was found in a real water sample. Therefore, the extraction method was successfully applied to the detection and quantification of multiple classes of antibiotics in different aqueous systems with satisfactory results

Recent developments on solid phase microextraction (SPME) coatings for in vivo analysis

In vivo solid phase microextraction (in vivo SPME) has been regarded as a promising high-throughput sample preparation technique for bioanalysis fields in recent years due to its simplicity, great sensitivity and low invasiveness. Therefore, as the key driving force of the development of this technique, many important advances have been also made in biocompatible coating materials. In view of this, this review here focused on various types of materials that are currently popular as in vivo SPME coating for both the targeted and untargeted analysis in living system. The main performance of each exemplary material and its current application as an in vivo SPME extraction phase were summarized in detail. As was shown, the development and the improvement of coating materials make in vivo SPME display a great potential for the targeted and untargeted screening of small molecules in living organisms. Finally, it was emphasized that the implementation of in vivo SPME in the fields of bioanalysis should be more concerned as long as suitable coating materials are available

Enhanced Performance and Stability of a Trimetallic CuZnY/SiBEA Catalyst in Ethanol to Butadiene Reaction by Introducing Copper to Optimize Acid/Base Ratio

Bioethanol to butadiene is currently the most promising non-oil-based butadiene production route. Here, copper is introduced into the conventional bimetallic zeolite catalyst to partially substitute for zinc; the isolated tetracoordinated Cu(II) species are formed, with weak and strong basic sites transformed into medium acid sites in trimetallic CuZnY/SiBEA catalyst. A partial substitution of zinc by copper increases the dispersion of metal, reduces the formation of ZnO clusters, decreases the pore blockage, and enhances the total pore volume of catalyst. The Cu1Zn2Y5/SiBEA catalyst with an appropriate 0.33 Cu/(Cu + Zn) mass ratio, a highest medium acid sites/(weak + strong) basic sites value of 6.17, and largest total pore volume of 0.251 cm3/g in all samples presents excellent catalytic performance in the ethanol to butadiene reaction: 99.01% ethanol conversion and 73.36% butadiene selectivity, higher than most reported ethanol to butadiene catalysts. The isolated tetracoordinated Cu(II) structure is stable, which is beneficial to the stability of trimetallic catalyst; when the reaction time is 60 h, the butadiene selectivity is 45.95%, 14% higher than corresponding bimetallic catalyst. The butadiene productivity of Cu1Zn2Y5/SiBEA catalyst reaches up to 1.68 gBD·gcat−1·h−1 at WHSV = 6 h−1 and time-on-stream = 8 h. Increasing reaction temperature could linearly increase the ethanol conversion, while the butadiene selectivity increases first and then decreases, the suitable temperature is 375 ℃ for the highest butadiene yield

Applications of in vivo SPME based on mass spectrometry for environmental pollutants analysis and non-target metabolomics: A review

In vivo analysis of environmental organic pollutants and endogenous metabolites has great impacts on understanding their environmental behavior and exposure risks. This calls for the development of convenient and reliable analytical methods with either high specificity or wide coverage of target compounds in complex matrixes. Different from traditional solvent extraction, solid-phase microextraction (SPME) has emerged as an integrated sample preparation technique by combining sampling, extraction, and cleanup into one step, which exerts great potential on in vivo sampling due to its high sensitivity and low invasiveness. In this view, the design principles of SPME fibers for in vivo sampling, novel SPME fibers, and devices over recent years are summarized for the guidance of SPME fiber design. The applications of in vivo SPME on monitoring uptake, translocation, and degradation of environmental organic pollutants in organisms, as well as non-target metabolomics in environmental toxicology and clinical analysis based on mass spectrometry, are described. SPME fiber directly coupled with mass spectrometry for in vivo analysis has been introduced. The practical limitations and prospects of further research are also discussed. We conceive that in vivo SPME will promote the development of environmental analysis and toxicity assessment in a high-efficiency and high-throughput manner

Enhanced Performance and Stability of a Trimetallic CuZnY/SiBEA Catalyst in Ethanol to Butadiene Reaction by Introducing Copper to Optimize Acid/Base Ratio

Bioethanol to butadiene is currently the most promising non-oil-based butadiene production route. Here, copper is introduced into the conventional bimetallic zeolite catalyst to partially substitute for zinc; the isolated tetracoordinated Cu(II) species are formed, with weak and strong basic sites transformed into medium acid sites in trimetallic CuZnY/SiBEA catalyst. A partial substitution of zinc by copper increases the dispersion of metal, reduces the formation of ZnO clusters, decreases the pore blockage, and enhances the total pore volume of catalyst. The Cu1Zn2Y5/SiBEA catalyst with an appropriate 0.33 Cu/(Cu + Zn) mass ratio, a highest medium acid sites/(weak + strong) basic sites value of 6.17, and largest total pore volume of 0.251 cm3/g in all samples presents excellent catalytic performance in the ethanol to butadiene reaction: 99.01% ethanol conversion and 73.36% butadiene selectivity, higher than most reported ethanol to butadiene catalysts. The isolated tetracoordinated Cu(II) structure is stable, which is beneficial to the stability of trimetallic catalyst; when the reaction time is 60 h, the butadiene selectivity is 45.95%, 14% higher than corresponding bimetallic catalyst. The butadiene productivity of Cu1Zn2Y5/SiBEA catalyst reaches up to 1.68 gBD·gcat−1·h−1 at WHSV = 6 h−1 and time-on-stream = 8 h. Increasing reaction temperature could linearly increase the ethanol conversion, while the butadiene selectivity increases first and then decreases, the suitable temperature is 375 ℃ for the highest butadiene yield