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A fully automated photocolorimetric method for dissolved silica in oil well water rich in sulfide and bicarbonate is proposed; the method is based on yellow silicomolybdic heteropolyacid. To eliminate the interference of sulfide a treatment with bromate is utilized. The analytical range is 1–30mgL −1 ; with the automatically performed dilution it extends up to 300mgL −1 , RSD 5.5%.
The medicinal use of different chemovars and extracts of Cannabis sativa L. requires standardization beyond ∆9-tetrahydrocannabinol (THC) with complementing methods. We investigated the suitability of 1 H NMR key signals for distinction of four chemotypes measured in deuterated dimethylsulfoxide together with two new validated HPLC/DAD methods used for identification and extract profiling...
The abundance of lipids in plants is influenced by genotype and phenotype. Despite being a very important class of plant metabolites, knowledge of grape lipids is still very limited to date, with the exception of those located in seeds. Few investigations of grape lipids have shown that their profile depends on grape maturity, the variety and their location in the berry. Recent advances in liquid...
3-Nitrotyrosine (3-NT) has been widely adopted as a biomarker of oxidative stress. However, an enormous range of reported concentrations of 3-NT in biological matrices indicated an underlying methodological problem. Consequently, our understanding of tyrosine nitration in vivo and its significance as a biomarker may have been confounded. Here we report a fast, specific and sensitive LC–MS/MS method...
Monochloramine (MCA) may enter the aquatic environment through three main sources: wastewater treatment plant effluents, industrial effluents and thermal power plant wastes. Up to date, there are no available data about the concentration levels of this chemical in river water due to lack of appropriate analytical methods. Therefore, sensitive and selective analytical methods for monochloramine analysis...
Numerical simulation can provide valuable insights for complex microfluidic phenomena coupling mixing and diffusion processes. Herein, a novel finite element model (FEM) has been established to extract chemical reaction kinetics in a microfluidic flow injection analysis (micro-FIA) system using high throughput sample introduction. To reduce the computation burden, the finite element mesh generation...
In this work, we suggest a chitosan-modified popcorn-like Au–Ag nanoparticles (CSPNPs) based assay for high sensitive detection of melamine, in which CSPNPs not only provide with an intrinsic peroxidase-like activity but also act as surface enhanced Raman scattering (SERS) substrates. CSPNPs can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H 2 O 2 to the charge...
One of the hypotheses that may help explain the loss of honey bee colonies worldwide is the increasing potential for exposure of honey bees to complex mixtures of pesticides. To better understand this phenomenon, two multi-residue methods based on different extraction and cleanup procedures have been developed, and compared for the determination of 11 relevant pesticides in honey bees, pollen, and...
Polyethyleneimine (PEI)-grafted and 3-acrylamidophenylboronic acid (AAPBA)-functionalized SiO 2 boronate affinity materials were synthesized for the selective enrichment of cis-diol-containing compounds. Characterization results of scanning electron microscopy, Fourier transform infrared spectroscopy, elemental analysis, zeta potential, and X-ray photoelectron spectroscopy indicated the successful...
An improved decontamination method and ultraclean analytical procedures have been developed to minimize Pb contamination of processed glacial ice cores and to achieve reliable determination of Pb isotopes in North Greenland Eemian Ice Drilling (NEEM) deep ice core sections with concentrations at the sub-picogram per gram level. A PL-7 (Fuso Chemical) silica-gel activator has replaced the previously...
An important trend in the extraction of chemical compounds is the application of new environmentally friendly, food grade solvents. Ethyl lactate (ethyl 2-hydroxypropanoate), produced by fermentation of carbohydrates, is miscible with both hydrophilic and hydrophobic compounds being a potentially good solvent for bioactive compounds. Despite its relatively wide use as a general solvent, the utilization...
A new method for real-time detection of carcinoembryonic antigen (CEA) in human serum with high sensitivity and selectivity using surface plasmon resonance (SPR) biosensor was developed. Two kinds of antibodies were used to recognize CEA at different epitopes with high affinity and specificity. Gold nanoparticles (GNPs) modified with streptavidin (SA) were used to further enhance signal specifically...
Nitrogen dioxide (NO 2 ) is an important indicator of atmospheric pollution that is mainly derived from combustion processes. The gas is often present at undesirable levels in both open and closed environments worldwide, requiring monitoring under a variety of different conditions. This work describes the development of a sensitive, selective, and inexpensive method for the determination of...
The introduction of new compact systems for sensitive, fast and simplified analysis is currently playing a substantial role in the development of point-of-care solutions aimed to assist both prognosis and diagnosis. Here we report a simple and low cost biosensor based on Surface Plasmon Resonance (SPR) taking advantage of a plastic optical fiber (POF) for the detection of Vascular endothelial growth...
The gas phase ion chemistry for an ion mobility spectrometer (IMS) based explosive detector has been elucidated using tandem mass spectrometry. The IMS system, which is operated with hexachloroethane and isobutyramide reagent gases and an ion shutter type gating scheme, is connected to the atmospheric pressure interface of a triple quadrupole mass spectrometer (MS/MS). Product ion masses, daughter...
The present study (1) reports on the synthesis of two hybrid silica monoliths functionalized with aminopropyl or cyanopropyl groups by the sol–gel process; (2) evaluates these monoliths as selective stationary phase for microextraction by packed sorbent (MEPS) to determine drugs in plasma samples via liquid chromatography–tandem mass spectrometry (LC–MS/MS) in the multiple reactions monitoring (MRM)...
H3K14ac (acetylation of lysine 14 of histone H3) is one of the most important epigenetic modifications in cells. Aberrant changes in H3K14ac are commonly found in various types of cancers and neurological disorders. Current detection approaches for histone modifications, however, require either tedious sample pre-treatments or lack the quantitative accuracy required for biochemical and biomedical...
In order to suppress the fragmentation and improve the sensitivity for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs), the mechanism of multiphoton ionization was studied for the following representative NPAHs, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene. The analytes were extracted from the PM 2.5 on the sampling filter ultrasonically, and were measured using...
An ultrasensitive electrochemical immunosensor for detection of Salmonella has been developed based on using high density gold nanoparticles (GNPs) well dispersed in chitosan hydrogel and modified glassy carbon electrode. The composite film has been oxidized in NaCl solution and used as a platform for the immobilization of capture antibody (Ab 1 ) for biorecognition. After incubation in Salmonella...
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