•The matrix effect of the proposed method is significantly decreased by using MMIPs as sorbent.•MMIP can provide a rapid and easy way for separation due to its magnetism.•Extraction and enrichment were completed in a single step.In this paper, a simple and reproducible method for the determination of roxithromycin in human plasma samples is proposed. The surface magnetic molecularly imprinted polymers (MMIPs) were utilized as sorbent. Roxithromycin was used as imprinted compound. The experimental results showed that the MMIPs had high affinity and selectivity toward roxithromycin. The extraction process was carried out in a single step by mixing the extraction solvent, MMIPs and human plasma samples by vortex. When the extraction process was completed, the MMIPs adsorbed the analyte were separated from the sample matrix by an external magnet due to the magnetism. The analyte eluted from the MMIPs was analysed by liquid chromatography-tandem mass spectrometry. Some main factors affecting the extraction of roxithromycin such as the amount of MMIPs, extraction solvent, extraction time, washing and elution conditions were optimized in this study. The calibration curve obtained by analyzing matrix-matched standards showed excellent linear relationship (r2 = 0.9997) in the concentration range of 10–1000 ng mL−1. The limit of detection and quantification obtained were 3.8 and 9.8 ng mL−1, respectively. The relative standard deviations of intra- and inter-day obtained were in the range of 3.9 %–5.5 % and 2.9 %–4.6 % with the recoveries ranging from 86.5 % to 91.5 %.

A simple and effective method based on magnetic separation has been developed for the extraction of sulfonamides (SAs) from egg samples using magnetic multiwalled carbon nanotubes (MMWCNTs) as an adsorbent. The MMWCNTs were simply prepared by depositing Fe3O4 onto MWCNTs that had been previously oxidised. The extraction procedure was carried out in a single step by blending and subsequently stirring the mixture of MMWCNTs and aqueous egg samples. The SAs were first extracted as described above, adsorbed onto the MMWCNTs directly and finally analysed by liquid chromatography–tandem mass spectrometry. The limits of detection obtained are in the range of 1.4–2.8 ng g−1. The proposed method was successfully applied in determining SAs in the eggs obtained from laying hens fed with SA standards, and compared to eggs purchased from local markets. The results demonstrate that SAs were detectable in the incurred egg samples.Highlights► Using magnetic multiwalled nanotubes as adsorbents. ► Easier preparation and regeneration of the adsorbents. ► Simpler sample handling procedure due to the application of magnetic separation technology. ► Extraction and enrichment procedures could be fulfilled simultaneously. ► Less solvent consumption and higher extraction efficiency.

The objective of conducting experiments in a laboratory is to gain data that helps in designing and operating large-scale biological processes. However, the scale-up and design of industrial-scale biohydrogen production reactors is still uncertain. In this paper, an established and proven Eulerian–Eulerian computational fluid dynamics (CFD) model was employed to perform hydrodynamics assessments of an industrial-scale continuous stirred-tank reactor (CSTR) for biohydrogen production. The merits of the laboratory-scale CSTR and industrial-scale CSTR were compared and analyzed on the basis of CFD simulation. The outcomes demonstrated that there are many parameters that need to be optimized in the industrial-scale reactor, such as the velocity field and stagnation zone. According to the results of hydrodynamics evaluation, the structure of industrial-scale CSTR was optimized and the results are positive in terms of advancing the industrialization of biohydrogen production.

An automated on-line solid-phase extraction–liquid chromatography–tandem mass spectrometry (SPE–LC–MS/MS) system was developed for the determination of macrolide antibiotics including erythromycin (ETM), roxithromycin (RTM), tylosin (TLS) and tilmicosin (TMC) in environmental water samples. A Capcell Pak MF Ph-1 column packed with restricted access material (RAM) was used as SPE column for the concentration of the analytes and clean-up of the sample. One milliliter water sample was injected into the conditioned SPE column and the matrix was washed out with 3 mL high purity water. By rotation of the switching valve, macrolides (MLs) were eluted in the back-flush mode and transferred to the analytical column by the chromatographic mobile phase. The matrix effect was evaluated by the directly injection LC–MS and on-line SPE–LC–MS methods. The limits of detection (LODs) and limits of quantification (LOQs) obtained are in the range of 2–6 and 7–20 ng L−1, respectively, which means that the proposed method is suitable for trace analysis of MLs at low level concentration. The intra- and inter-day precisions are in the range of 2.9–7.2% and 3.3–8.9%, respectively. In the three fortified levels (20, 200 and 2000 ng L−1), recoveries of MLs ranging from 86.5% to 98.3% are obtained.

In this work, the effects of different parameters on co-culture hydrogen production using Clostridium Butyricum and immobilized Rhodopseudomonas faecalis RLD-53 were investigated. The maximum hydrogen yield of 4.134 mol H2/mol glucose was obtained using 6 g/l glucose, 50 mmol/l phosphate buffer, initial pH of 7.5, the ratio of dark to photo bacteria of 1:10 and light intensity of 8000 lux. The maximum hydrogen production rate was 33.85 ml H2/l/h. Phosphate buffer concentration was the most important parameter influencing hydrogen production in this co-culture. The ratio of acetate to butyrate increased from 0.74 to 1.82 in the soluble metabolites from C. butyricum with phosphate buffer concentration of 10–50 mmol/l. Experimental results could be of great significance for further pilot studies of co-culture hydrogen production.

Understanding how a bioreactor functions is a necessary precursor for successful reactor design and operation. This paper describes a two-dimensional computational fluid dynamics simulation of three-phase gas–liquid–solid flow in an expanded granular sludge bed (EGSB) reactor used for biohydrogen production. An Eulerian–Eulerian model was formulated to simulate reaction zone hydrodynamics in an EGSB reactor with various hydraulic retention times (HRT). The three-phase system displayed a very heterogeneous flow pattern especially at long HRTs. The core-annulus structure developed may lead to back-mixing and internal circulation behavior, which in turn gives poor velocity distribution. The force balance between the solid and gas phases is a particular illustration of the importance of the interphase rules in determining the efficiency of biohydrogen production. The nature of gas bubble formation influences velocity distribution and hence sludge particle movement. The model demonstrates a qualitative relationship between hydrodynamics and biohydrogen production, implying that controlling hydraulic retention time is a critical factor in biohydrogen-production.