Coupling of solid phase microextraction with electrospray ionization ion mobility spectrometry and direct analysis of venlafaxine in human urine and plasma

The capability of electrospray ionization-conventional ion mobility spectrometry (ESI–IMS) for direct analysis of the samples extracted by solid phase microextraction (SPME) was investigated and evaluated for the first time. To that end, an appropriate new desorption chamber was designed and constructed, resulting in the possibility of direct exposure of the SPME fiber to the electrospray solvent flow. Two different elution methods in dynamic and static modes were exhaustively investigated. The results indicated that the interface could help us to have an accurate and sensitive analysis without disturbing the electrospray process, in static elution method. Venlafaxine as a test compound was extracted from human urine and plasma by a convenient headspace SPME method. The positive ion mobility spectrum of the extracted drug was obtained and the analyte responses were calculated. The coupled method of SPME–ESI–IMS was comprehensively validated in terms of sensitivity, dynamic range, and recovery percentage. Finally, various real samples of human urine and plasma were analyzed, all verifying the feasibility and success of the proposed method for the easy routine analysis.     

Fabrication of the Metal-Organic Framework Membrane with Excellent Adsorption Properties for Paraben Based on Micro Fibrillated Cellulose

A kind of novel environmental-friendly composite absorbent material was designed and prepared in this paper. Nanoscale metal-organic frameworks(MOFs) were embedded in the skeleton of cotton micro fibrillated cellulose. By scanning electron microscope(SEM), we observed that a large number of MOFs were attached to the cellulose skeleton. In addition, under the condition of 1800 r/min vortex, the structure of the composite material was stable and was not easily damaged by external forces. The water contact angle test showed that the composite material had excellent hydrophilicity and could be used for the adsorption of pollutants. Then, the material was characterized by energy dispersive X-ray spectroscopy(EDX), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR) and BET adsorption. Through verification, the material had very stable reusability(n=10). The composite material was applied to the solid phase extraction of water samples, such as rain water, toning water and fruit juice, and was quantitatively analyzed by high performance liquid chromatography(HPLC)-UV. This method was then applied to the extraction of four parabens(methyl-, ethyl-, propyl-, and butyl-paraben) from real samples, yielding limits of detection(LODs) of 0.29-0.58 ng/mL. The linear range was 2-500 ng/mL. The inter-day and intra-day recoveries were 90.7%-106.0% and 87.1%-109.3%, respectively(relative standard deviation<10.8%).     

An insight on sampling,identification, quantification and characteristics of microplastics in solid wastes

Microplastics (MPs) have attracted wide attention all over the world as a remarkable pollutant. While MPs are spreading throughout several complex environmental matrices, various experiments till date have been preliminary concentrate on aquatic ecosystems. Terrestrial sources namely solid waste-origin have remains unexplored, although they contribute largely for aquatic microplastics origin. Simultaneously, terrestrial systems under human activity, like healthcare units, are likely to be polluted by various plastic ingredients. Solid waste MPs sources primarily include sanitary landfilling, food waste, wastewater treatment end-product (sludge), tire wear, textile washing and paint failure. These microplastics caused adverse impacts on ecosystem, environment, and health. Accordingly, the present study addressed solid waste MPs’ occurrence and sources, identification, quantification, characterization, fate, and degradation pathways for developing comprehensive management strategies following the principles of circular economy. In particularly, this paper critically demonstrated solid waste MPs sources, solid waste MPs sampling followed by identification and quantification by adopting combined chemical (e.g., spectroscopy viz., Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy), physical (e.g., microscopy such as transmission or scanning electronic microscopy, TEM or SEM) and thermal analyses. Additionally, the strengths and limitations of each analytical technique are discussed critically with practical aspect. Further, the MPs related national and international regulations or laws and their subsequent relevance to solid waste MPs management with future challenges are discussed very critically. Finally, the outcomes of the review paper will be valuable to different stakeholders for effective policy implementation.     

介孔SO42-/Zr-SBA-15催化废弃油制生物柴油

采用廉价的无机锆源(无水硝酸锆)通过一步法合成表面含强Lewis酸位的SO₄^2-/Zr-SBA-15,该催化剂材料在废弃食用油和甲醇酯交换制生物柴油过程中表现出良好的催化活性和选择性. 实验考察了酯交换反应的最佳条件为：反应温度160 oC、反应时间12 h、催化剂Zr:Si为0.11、催化剂用量为10%、醇油比30:1. SO₄^2-/Zr-SBA-15在最佳反应条件下可使甘油三酯的转化率达到92.3%,脂肪酸甲酯的产率为91.7%. SO₄^2-/Zr-SBA-15具有高比表面积的介孔结构和表面酸性,且具有良好的反应稳定性和重复性,反应7次后的脂肪酸甲酯的产率仍稳定保持在74 ±1%.     

CO2对Ba0.5Sr0.5Co0.8Fe0.2O3−δ表面氧交换的影响

采 用 了 一 种 新 的 脉 冲 同 位 素 交 换 技 术 , 研 究了CO₂对Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3?δ(BSCF)的表面氧交换动力学的毒害作用．当BSCF暴露于CO₂时,由于在材料表面形成了碳酸盐,其表面交换率严重降低．在低CO₂浓度(1%)时,毒害作用从375 oC开始,并且随着温度的上升而变得更加明显．同时,表面交换动力学的下降导致BSCF在CO₂条件下氧渗透性能快速下降．     

Discrimination between 2AP producing and non‐producing rice rhizobacterial isolates using volatile profiling: a chemometric approach

2‐Acetyl‐1‐pyrroline (2AP) is known as a principal basmati aroma compound. The present study aims at discriminating rhizobacteria isolated from soils cultivated with basmati and non‐basmati rice for long duration. Volatile profiling was used as marker to discriminate the rhizobacterial isolates. Quantification of 2AP and other volatile compounds (VCs) produced by rhizobacteria was undertaken using HS‐SPME coupled with GC‐MS. Chemometrics tools such as hierarchical cluster analysis (HCA), principle component analysis (PCA) and multi dimensional scaling (MDS) were applied for volatile profiling of different isolates. Results showed significant discrimination of all 2AP producing (AP‐P) and non‐producing rhizobacterial isolates (AP‐NP) on the basis of their VC profile. This was validated by bacterial identification data as well. The frequency distribution for 2AP levels indicates that basmati isolates had higher frequency for 2AP production as compared to non‐basmati control. AP‐P and AP‐NP isolates have different VC profiling pattern irrespective of their origin. These isolates were found belonging to different groups when identified using 16S rDNA sequencing data. Chemometric analysis (PCA, HCA and MDS) helped to identify volatiles, which could be used as biomarker in discriminating the AP‐P and AP‐NP isolates. VC pattern of rhizobacteria could be used as volatile markers to distinguish between AP‐P and AP‐NP rhizobacterial isolates. Copyright © 2015 John Wiley & Sons, Ltd.     

Growth of epitaxial TmFeCuO4 thin films by pulsed laser deposition

Epitaxial thin films of TmFeCuO₄ with a two-dimensional triangular lattice structure were successfully grown on yttria-stabilized-zirconia substrates by pulsed laser deposition and ex situ annealing in air. The films as-deposited below 500 °C showed no TmFeCuO₄ phase and the subsequent annealing resulted in the decomposition of film components. On the other hand, as-grown films deposited at 800 °C showed an amorphous nature. Thermal annealing converted the amorphous films into highly (0 0 1)-oriented epitaxial films. The results of scanning electron microscopic analysis suggest that the crystal growth process during thermal annealing is dominated by the regrowth of non-uniformly shaped islands to the distinct uniform islands of hexagonal base.     

Impact of amorphous Ge thin layer at the amorphous Si/Al interface on Al-induced crystallization

We investigated the impact of an amorphous Ge (a-Ge) thin layer inserted at the amorphous Si (a-Si)/Al interface on Al-induced crystallization. In situ observation of the growth process clarified that the nucleation rate is drastically reduced by insertion of a-Ge, which led to increase in the average size of crystal grains. This was interpreted as resulting from decrease in the driving force of crystallization, mainly due to the larger solubility of Ge in Al than that of Si in Al. The obtained films were SiGe alloys with lateral distribution of Ge content, and its origin is discussed based on the two-step nucleation process.     

Preparation and physical properties of (PVA)0.75(NH4Br)0.25(H2SO4)xM solid acid membrane

In this work, solid acid membrane consisting of poly(vinyl alcohol) (PVA), ammonium bromide (NH₄Br) and sulfuric acid (SA) has been prepared by a solution casting technique method. X-ray diffraction of the (PVA)_0.75(NH₄Br)_0.25(H₂SO₄)_xM polymer matrix and pure (PVA)_0.75(NH₄Br)_0.25 revealed the difference in crystallinity between them. The effect of different amounts of SA on the conductivity of the polymer electrolytes was studied. The ionic conductivity of the prepared electrolytes can reach 3.1 × 10⁻² S cm⁻¹ at room temperature. The conductivity measurements carried out at different temperatures indicate that all the films follow Arrhenius behavior and that the activation energy decreases with the increase in SA concentration. The a.c. conductivity seems to follow the universal power law.     

纳米二氧化钛富集-分光光度法测定水体中痕量5-磺基水杨酸

采用纳米TiO2化学吸附法富集水样中痕量5-磺基水杨酸。5-磺基水杨酸含有酚羟基(OH)和羧基(COOH)可与TiO2表面上的羟基(OH)发生酯化反应,形成稳定的六元环结构。纳米TiO2对5-磺基水杨酸的吸附量≤18.47mg/g,在pH2.5、吸附时间20min、吸附剂用量1.80g/L的条件下,纳米TiO2对试样中5-磺基水杨酸的吸附率达到99.0%,以5mL2mol/L NaOH为洗脱液,洗脱率达99.8%,对试样中5-磺基水杨酸的富集倍数达50倍,检出限(3σ,n=11)为26.7μg/L。本法操作简便,直接用于九龙江和海水中痕量5-磺基水杨酸的测定,结果准确,回收率达到95.5%～98.5%。