Chungburke3463

For spiked samples of hair hydrolyzate, recovery was between 88 and 120%, whereas precision and intermediate precision were below 10.1%. The high sensitivity of the method made it possible to reduce sample preparation to a 10000-fold dilution of the raw hydrolyzate. The wide linear range displayed by the method allowed the simultaneous quantification of minor (0.3 μmol/g of hair) and major (up to 1000 μmol/g of hair) components of the biological fiber. Apoptozole clinical trial This method was successfully applied to the analysis of real hair samples submitted to six different treatments. Statistical data analysis by means of t-test and principal component analysis (PCA) showed a clear discrimination of the treated from the untreated hair samples and of the different treatments. Since these hair treatments can interfere with hair drug testing, the method possesses the ability of identifying hair samples with potential for attempted drug test evasion. In addition, lanthionine emerged as a new biomarker for heat damaged hair.Carbon nanospheres (CNSs) were derived hydrothermally from biomass (orange peels) and decorated by manganese dioxide (MnO2) nanosheets. The MnO2/CNSs nanocomposite was intercalated into polypyrrole (PPy) during flow-through in-situ electropolymerization of pyrrole on the surface of the inner wall of a stainless-steel needle to prepare an inside-needle capillary adsorption trap (INCAT) device. The surface morphology, thermogravimetric behavior, sorption characteristics, and structure of the MnO2/CNSs@PPy nanocomposite were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), nitrogen physisorption by the Brunauer-Emmett-Teller (BET) method, dynamic light scattering (DLS) size distribution, and Fourier-transform infrared spectrometry (FT-IR). The INCAT device was coupled with GC-FID and applied for dynamic headspace analysis of linear alkyl benzenes (LABs) in wastewater samples. The effective experimental variables on the extraction efficiency was optimized using a central composite design (CCD) based on response surface methodology (RSM). Under the optimal conditions, the limits of detection (LODs) were in the range of 0.5-1.0 ng mL-1. The calibration plots were linear over the range of 0.01-10 μg mL-1. The relative standard deviations (RSDs%) for intra-day, inter-day, and inter-INCAT precision were calculated 5.3-8.3%, 9.4-13.5%, and 13.6-16.9%, respectively. The developed technique was employed successfully for the analysis of LABs in water and wastewater samples with average recovery values ranging from 92 to 109%. A single INCAT device was used more than 90 times without significant change in its extraction capability.Isoflavones are a group of phytoestrogens of important environmental concern due to their endocrine disrupting effects. This article presents a rapid, green, and sustainable method for determining four isoflavones (daidzein, genistein, formononetin, and biochanin A) in environmental waters complying with current trends in Analytical Chemistry. The method consists of in-syringe dispersive solid-phase extraction (DSPE) as the extraction approach, using carbon fibers as extraction material. The synthesis of carbon fibers is simple and sustainable, since it only requires a natural product such as raw cotton as precursor, which is thermally treated (600 °C for 30 min) in an inert (Ar) atmosphere to convert it into carbon fibers. After extraction, the final eluate is analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proposed methodology allows the determination of the four isoflavones in water samples at the ng L-1 range, with limits of detection in the range from 17 to 25 ng L-1, relative standard deviations (RSD) from 2.8 to 10.1%, and good batch-to-batch repeatability (RSD less then 13%). The method was finally applied to six environmental water samples from different sources and two swimming pool waters, and concentrations of all analytes up to 490 ng L-1 were found. The highest concentrations were found in those samples close to crop fields. Relative recovery values (80-121%) showed that the aqueous matrices considered in this work did not significantly affect the extraction process. This method overcomes the drawbacks of the previous works with the same purpose, such as consuming large volumes of organic solvents or prolonged extraction times. Moreover, this procedure would allow the extraction stage to be carried out in situ, since only the sorbent material (previously synthesized in the laboratory) and disposable syringes are required.A novel near-infrared-emitting aza-BODIPY-based fluorescent probe with two tellurium atoms at two upper benzyl rings has been prepared and explored for its fluorescent sensing properties towards hypochlorous acid/hypochorite (HClO/ClO-), which showed high selectivity and absolutely fluorescent "turn-on" phenomenon at 738 nm. The fluorescence of this probe was sufficiently quenched due to photoindued electron transfer by two tellurium atoms. Upon exposure to HClO/ClO-, a strong near-infrared emission at 738 nm appeared with fluorescence quantum yields changing from 0 to 0.11. This remarkable fluorescence change was ascribed to the oxidation of both electron-rich tellurium atoms. The detection limit of this probe towards HClO/ClO- was calculated to 0.09 μM in acetonitrile aqueous solution by the linear fluorescence change at 738 nm in the HClO/ClO--concentration range of 0-30 μM. Interestingly, this probe was found to be applicable in a broad pH range (2-10). Meanwhile, the oxidized probe could be further responsive to biothiols with substantial fluorescence disappearance. The bioimaging experiments in RAW264.7 cells showed the appearance of intracellular near-infrared fluorescence after addition of HClO/ClO- and PMA, and the fluorescence could also be reversed to be silenced by further introduction of GSH, confirming its potential application for exogenous and endogenous detection of HClO/ClO- in living cells.Current miniature mass spectrometers were usually designed for the detection of small and medium size molecules, including volatile (semi-volatile) compounds, drugs and lipids. In this study, a miniature protein mass spectrometer was developed in this work, which could serve as a biosensor for the rapid identification of proteins as well as their conformations. A linear ion trap with a field radius of 2.5 mm was designed to extend mass range of the instrument to over 6500 Th. Mass resolution and sensitivity of the instrument were also optimized for protein ions by increasing the buffer gas pressure and using a high-gain Faraday detector. It is then demonstrated that the mass spectra of native proteins, such as IgG1, could be acquired by coupling the instrument with a soft electrospray ionization source. As a proof-of-concept demonstration, results suggest that the current instrument could be used to identify target proteins and probe/distinguish their conformations in solutions.