Notes

The intestine microbiota and also microbe metabolites are usually connected with butt biting in pigs.
Glycerol is widely used as humectant in cosmetics to improve skin's smoothness and moisture. However, its level must be controlled in cosmetics at the risk of causing irritation or allergy. Therefore, determining glycerol concentration in environmental waters with more advanced, inexpensive and accurate sensing systems is of great importance. In this work, a fast, simple, portable and cheap molecular imprinted polymer (MIP) approach is used to develop an electrochemical sensor for glycerol determination. The MIP based screen-printed gold electrode (Au-SPE) is prepared by electro-polymerizing Acrylamide/Bisacrylamide (AAM/NNMBA) and gold nanoparticles (AuNPs) in the presence of glycerol as a template. Techniques, such as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) are used for electrochemical measurements. Energy-dispersive X-ray spectroscopy (EDS) is utilized to characterize the chemical composition analysis. In contrast to its high response towards glycerol, the electrochemical sensor exhibits negligible responses when exposed to interfering species, such as glycolic acid, glycerol monostearate, tartaric acid, sodium citrate, ammonium sulfate, decyl-glucoside, caprylyl glucoside and glutamic acid. Under optimal experimental conditions, a detection limit (LOD) as low as 0.001 μg/mL (signal-to-noise ratio S/N = 3) is calculated over a linear concentration range (20.00-227.81 μg/mL). Interestingly, the sensor was successfully applied to wastewater samples relating to glycerol determination with a relative standard deviation (RSD) less than 4%. Besides, the reproducibility, the working and storage stabilities of the sensor were proven. According to these outcomes, the electrochemical MIP sensor could be viable enough to detect the presence and levels of pollutants in real water samples.A flow-based method for the spectrophotometric determination of iron in recreational waters, both fresh and marine (variable salinity content), was developed. For that purpose, 3-hydroxy-4-pyrydinone ligand functionalized with an ether function was synthetized and used as chromogenic chelator (1-(3'-methoxypropyl)-2-methyl-3-benzyloxy-4-(1H)pyridinone - MRB13) for iron quantification. This water-soluble reagent was previously reported as a greener alternative to quantify iron, due to its low toxicity and a more environmental friendly synthesis. Furthermore, it also displayed a high affinity and specificity for iron. With the main objective of quantifying iron in a variety of water types (different matrices and iron content), two strategies were developed, one of them including on-line solid-phase extraction (SPE), and the other without resorting to a SPE process. Water matrix clean-up and iron enrichment was achieved using a nitrilotriacetic acid resin column. The potential interference of metal ions usually present in water samples was assessed and no significant interference ( less then 10%) was observed. The limits of detection were 11 and 2.9 μg L-1 without and with SPE, respectively. For one determination (three replicates), the corresponding consumption of MRB13 is 90 μg, sodium hydroxide is 1.4 mg, and boric acid is 5.6 mg. The method was applied to certified water samples and the results were in agreement with certified values. The developed method was also applied to fresh and marine water, and recovery ratios of 103 ± 4 and 101 ± 7 without and with SPE, respectively, were achieved.A porous polymer membrane-based d-amino acid oxidase (DAAO) reactor was developed that mimicked enzymatic activity in a renal ischemia model. Using glycidyl methacrylate as a biocompatible reactive monomer, poly(styrene-glycidyl methacrylate) was synthesized via a reversible addition fragment chain transfer polymerization technique. The prepared porous polymer membrane was used as a support to effectively immobilize DAAO. Compared to DAAO modified on nonporous polymer membrane and free DAAO in solution, the constructed porous polymer membrane-based DAAO enzyme reactor displayed 3-fold and 19-fold increase in enzymolysis efficiency, respectively. In addition, a chiral ligand exchange capillary electrophoresis system for DAAO was used to study DAAO enzymatic kinetics with d,l-methionine as the substrate. The proposed porous polymer membrane-based enzyme reactor showed excellent performance both on reproducibility and stability. Moreover, the enzyme reactor was successfully applied to mimic DAAO activity in a renal ischemia model. These results demonstrated that the enzyme could be efficiently immobilized onto a porous polymer membrane as an enzyme reactor and has great potential in mimicking the enzymatic activity in kidney.This work reports the development of an electrochemical immunosensor for rapid, specific and decentralized detection of the invasion-associated protein p60 secreted by Listeria monocytogenes, a life-threatening foodborne pathogen. A disposable screen-printed electrode was used as transducer surface and monoclonal and polyclonal antibodies that specifically recognize Listeria monocytogenes p60 protein and Listeria spp. p60 proteins, respectively, were used as the sandwich immuno-pair. The reaction was detected with the aid of an additional secondary antibody conjugated with the enzyme reporter (alkaline phosphatase) and using 3-indoxyl phosphate/silver ions as the mixture substrate. The analytical signal was acquired through the voltammetric stripping of the enzymatically deposited silver, which was directly correlated to p60 concentration in the sample. In optimized conditions, a limit of detection and quantification of 1.5 ng mL-1 and 5.1 ng mL-1 were achieved, respectively, in a useful time ( less then 3 h). selleck kinase inhibitor As proof-of-concept, the proposed immunosensor was successfully applied to spiked milk samples, demonstrating to be a suitable device for further use in real sample detection of Listeria monocytogenes in food products.A cost-effective, automated and portable IC has been developed for in-situ analysis of nitrite and nitrate in natural waters. The system employed 3D printed pumps for eluent delivery and a deep-UV LED based optical detector. Isocratic separation and selective detection of nitrite and nitrate was achieved in under 3 min. The total weight of the analyser was ~11 kg, and included electronics along with a sample intake system for automated analysis. Linear calibration ranges were generated using different sample injection loops. Using a 150 μL loop, an analytical range (0.05-30 mg L-1 NO2-, 0.10-75 mg L-1 NO3-) suitable for freshwater analysis was generated, while using a 10 μL loop an analytical range (0.30-100 mg L-1 NO2-, 2.5-500 mg L-1 NO3-) suitable for effluent and domestic wastewater analysis was achieved. Chromatographic repeatability demonstrated by the system is graphically presented and RSD values of less then 4% were obtained in terms of peak area and retention time over 82 sequential runs. The system was deployed in-situ at multiple sites for varying deployment periods analysing septic tank water, effluent from a waste water treatment plant and stream water.
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