Mccallkamp0104

1 ng/mL and 28.6 ng/mL respectively. Selected substances and drugs, known to react positively to Marquis and Mandelin reagents (used in AMP and MAMP presumptive testing) and well-known adulterants, were tested for their affinity to react with the aptamer-based GO-CTAB-AuNP-hemin peroxidase mimic biosensor. The deep blue colorimetric reaction, specific to AMP and MAMP detection, was used as the basis to affirm the selectivity of the aptamer-based GO-CTAB-AuNP-hemin peroxidase mimic biosensor. We believe the colorimetric biosensor developed in this work demonstrates a promising new direction in presumptive testing for AMP and MAMP.Challenged by the detection of trace amounts of mutants and disturbance from endogenous substances in clinical samples, herein, we present a novel electrochemical biosensor based on ligase chain reaction (eLCR) via the thermostable ligase with high mutation recognizing ability. The lengthened double-stranded DNAs exponentially generated via LCR were uniformly distributed on a bovine serum albumin-modified gold electrode, in which the phosphate buffer was tactfully added to remove adsorbed uninterested-probes, and thereafter the amperometry current was collected for the specific binding of streptavidin-poly-HRP and subsequent catalysis in the 3, 3', 5, 5'-tetramethylbenzidine substrate that contained hydrogen peroxide. It found that, under optimized conditions, the proposed biosensor exhibited a high selectivity of mutant targets from the 104-fold excess of co-existent wild targets within a detection limit of 0.5 fM. Impressively, without the involvement of pre-PCR, the homozygous mutants were specifically distinguished from the wild genotype of CYP2C19*2 allele in human whole blood samples. Therefore, the proposed eLCR, due to its advantages in simple primer design, operational ease and ease of miniaturization, has demonstrated its considerable potential for point-of-care testing in the diagnosis of point mutation-related diseases and personalized medicine.Edible oil adulteration is a main concern for consumers. This paper presents a study on the use of smartphone, coupled with image processing and chemometrics, to quantify adulterant levels in extra virgin olive oil. A sequence of light with varying colours is generated on the phone screen, which is used to illuminate oil samples. Videos are recorded to capture the colour changes on sample surface and are subsequently converted into spectral data for analysis. To evaluate the performance of this video approach, partial least squares regression models constructed from such video data as well as near-infrared, ultraviolet-visible and digital imaging data are compared in the task of quantifying the level of vegetable oil in extra virgin olive oil in the range 5%-50% (v/v). The results show that the video approach (R2 = 0.98 and RMSE = 0.02) yields comparable performance to baseline spectroscopy techniques and outperforms computer vision system approach. Since the smartphone-based sensor system is low-cost and easy to operate, it has high potential to become a consumer-oriented solution for detecting edible oil adulteration.Biomarkers of oxidative stress are generally measured in blood and its derivatives. However, the invasiveness of blood collection makes the monitoring of such chemicals during exercise not feasible. Saliva analysis is an interesting approach in sport medicine because the collection procedure is easy-to-use and does not require specially-trained personnel. These features guarantee the collection of multiple samples from the same subject in a short span of time, thus allowing the monitoring of the subject before, during and after physical tests, training or competitions. The aim of this work was to evaluate the possibility of following the changes in the concentration of some oxidative stress markers in saliva samples taken over time by athletes under exercise. To this purpose, ketones (i.e. acetone, 2-butanone and 2-pentanone), aldehydes (i.e. propanal, butanal, and hexanal), α,β-unsaturated aldehydes (i.e. acrolein and methacrolein) and di-carbonyls (i.e. glyoxal and methylglyoxal) were derivatized with 2,4-drease, approaching baseline values, of these compounds was observed in the recovery phase. This study opens up a new approach in the evaluation of oxidative stress and its relation to aerobic activity.As one of the transition metal dichalcogenide, CoSe2 has received much attention because of its superior physicochemical properties. In this work, a self-templated approach was proposed for constructing CoSe2 hollow microspheres by utilizing ZIF-67 hollow sphere as a template. In the followed selenylation process, selenium vapor reacts with cobalt ion in ZIF-67 to form CoSe2 microspheres. The obtained CoSe2 microspheres retain the cavity of the ZIF-67 and massive uniformly dispersed CoSe2 nanoparticles are embedded throughout carbon walls. The hollow interior and porous structure of CoSe2 microspheres provide an enhanced surface-volume ratio and short charge/mass transfer distance. The CoSe2 microspheres show a typical oxidase-like property able to promote 3,3',5,5'-tetramethylbenzidine (TMB) oxidation by dissolved oxygen to produce an intensive color reaction. Reactive oxygen species trials demonstrate that ·OH, 1O2 and O2•- radicals coexist in the TMB-CoSe2 system. Based on its inhibitive role, a rapid and ultrasensitive determination of glutathione was reached, showing four orders of magnitude linear range from 0.005 to 10 μM and a limit of detection of 4.62 nM (S/N = 3). The assay has been successfully used to glutathione determination in practical samples.Gadolinium-based contrast agents (GBCA) are widely used to enhance tissue contrast during magnetic resonance imaging (MRI) procedures. However, free Gadolinium (Gd) is undesirable as a drug substance, due to its high toxicity. Consequently, a coordinating ligand is required to keep it in solution and to increase tolerance. In order to achieve an adequate performance, GBCA must be administered in relatively large amounts. Chelate amounts are around 13-20 g and for Gd alone, this may amount to 3.3 g. Taking into account the route of administration, impurities in GBCA may be significant. Gadolinium occurs in nature along with 16 other elements known collectively as rare earth metals (RE), which are found throughout the earth's crust in minerals such as monazite. Gadolinium oxide corresponds to 0.7-4.0% of the RE present in minerals, and the sum concentration of RE in minerals is around 4%. Rare earth metals are difficult to separate, as the chemical and physical properties of one RE are significantly similar to (mean of 0.64 mg/L). Although the RE are chemically similar, the other RE do not perform as Gd as a contrast agent; therefore, their presence in formulations may be a matter of concern.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. Fasudil manufacturer 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.