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In this study, an on-line stacking capillary electrophoresis (CE) method, reverse-mode field amplified sample injection equipped with sweeping micellar electrokinetic chromatography (RMFASI-sweeping MEKC), was established for direct determination of uroporphyrin and coproporphyrin in human urine. Porphyrins playing a very important role in the biosynthesis of heme, chlorophyll and other important...
Recently, the International Agency for Research on cancer classified outdoor air pollution and particulate matter from outdoor air pollution as carcinogenic to humans (IARC Group 1), based on sufficient evidence of carcinogenicity in humans and experimental animals and strong mechanistic evidence. In particular, a wide variety of volatile organic compounds (VOCs) are volatized or released into the...
The direct electron transfer and electrocatalysis of hemoglobin (Hb) immobilized on the phosphonate functionalized multi-walled carbon nanotubes (MWCNTs) are investigated. Fourier transform infrared (FT-IR) spectra, UV–vis spectra and cyclic voltammetry (CV) analyses reveal that the phosphonate functionalized MWCNTs have good biocompatibility for Hb immobilization, and promote the electron communication...
The rapid and solvent-free determination of organophosphate esters (OPEs) in aqueous samples via one-step microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) followed by gas chromatography–mass spectrometry (GC–MS) analysis is described. Tri-n-butyl phosphate (TnBP) and tris-(2-ethylhexyl) phosphate (TEHP) were selected as model compounds for the method of development and validation...
Nonenzymatic electrochemical determination of ethanol and glucose was respectively achieved using PdNi- and Pd-coated electrodes prepared by electrodeposition from the novel metal-free ionic liquid (IL); N-butyl-N-methylpyrrolidinium dicyanamide (BMP-DCA). BMP-DCA provided an excellent environment and wide cathodic limit for electrodeposition of metals and alloys because many metal chlorides could...
CdS quantum dots (∼5nm) are used as multifunctional nanoprobes as an effective matrix for large proteins, peptides and as affinity probes for the enrichment of tryptic digest proteins (lysozyme, myoglobin and cytochrome c) in laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS). The use of CdS quantum dots (CdS QDs) as the matrix allows acquisition of high resolution LDI mass...
The electrochemistry of a macrocyclic metal complex Fe(notpH 3 ) [notpH 6 =1,4,7-triazacyclononane-1,4,7-triyl-tris(methylene-phosphonic acid)] reveals that the protonation/deprotonation of the non-coordinated P–OH groups in Fe(notpH 3 ) affects its formal potential value (E 0 ′) considerably. Plotting E 0 ′ as function of solution pH gives a straight line with...
The surface coverage of 3-mercaptopropylphosphonic acid (HS–CH 2 CH 2 CH 2 –PO 3 H 2 , MPPA) self-assembled monolayers (SAMs) on gold surface can be controlled by the dissociation degree of phosphonic acid groups (–PO 3 H 2 ) in the bulk solution and adsorption time of MPPA molecules under the basic condition. Electrochemical measurements show...
The direct electrochemistry of cytochrome c (cyt c) on a gold electrode modified with 3-mercaptopropylphosphonic acid [HS–(CH 2 ) 3 –PO 3 H 2 , MPPA] self-assembled monolayers (SAMs) was for the first time investigated. Electrochemical measurements and surface-enhanced infrared absorption spectroscopic reveal that the adsorption kinetics of cyt c on the MPPA-SAMs is...
An integrated method of liquid chromatography–heated electrospray ionization/tandem mass spectrometry was evaluated for high throughput screening of various abused drugs in urine. Chromatographic analysis was performed on a C18 reverse phase column using a linear gradient of 10mM ammonium acetate containing 0.1% formic acid–methanol as mobile phase and the total separation time was 7min. A simple...
The voltammetric behavior of hexavalent chromium species (Cr(VI)) was respectively studied at ITO, bulk Au, and Au-electrodeposited electrodes in 0.01M NaCl aqueous solutions containing 0.01M HCl. It was found that performance degradation of the ITO electrodes toward the reduction of Cr(VI) can be suppressed by modifying the electrode surface with gold nanoparticles (AuNPs), which were formed on ITO...
We have developed an analytical method by using liquid chromatography–mass spectrometry (LC–MS) to determine ketamine and its metabolites in urine. The ionization efficiency between two ionization modes (ESI and APCI) of LC–MS was compared to each other. An easy and simple sample preparation of urine samples was made by passing samples through a 0.22μm PVDF syringe filter. The results indicated that...
An integrated method of combining solid-phase microextraction (SPME) with liquid chromatography–mass spectrometry (LC–MS) was evaluated for determination trace amount of sulfonamides in meat products. Eight commonly used sulfonamides, sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMT), sulfamonomethoxine (SMMX), sulfamethoxazole (SMXZ), sulfaquinoxaline (SQX) and sulfadimethoxine...
A real-time and labeling-free surface plasmon resonance (SPR) sensor was used to monitor the conformational changes of immobilized globule proteins (RNase A and lysozyme) in chemical unfolding and refolding. The effects of chemical denaturants on the protein structures were investigated. The methodology in protein conformational study on the solid surface is refined through the theoretic calculations...
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