This paper describes a method for the determination of heterocyclic aromatic amines (HAs; DMIP, IQ, MeIQ, MeIQx, 4,8-DiMeIQx, 7,8-DiMeIQx, AalphaC, PhIP) by high-performance liquid chromatography (HPLC) with coulometric electrode array detection. The compounds are separated on reversed phase columns (LiChroCart Superspher 60 RP-select B, 250 mm x 2 mm, 4 microm and LiChrospher 60 RP-select B, 250 mm x 4 mm, 5 microm) using mobile phases consisting of acetonitrile/buffer/distilled water and detected at eight working electrodes at potentials between +190 and +680 mV against modified palladium electrodes. In the context of an EU-interlaboratory exercise, the method was applied to analyse a standardised test solution and--after isolation of the analytes by several clean-up steps--for the analysis of standardised beef extract and grilled meat. Further, the method could be applied for the analysis of HAs in suspensions of bacteria and rat urine without any sample preparation step beyond sample dilution. The data obtained show that HPLC with coulometric electrode array detection gives accurate results.
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http://dx.doi.org/10.1016/j.jchromb.2003.10.063 | DOI Listing |
ChemistryOpen
November 2024
Energy engineering, Division of Energy Science, Luleå, University of Technology, 97187, Luleå, Sweden.
We report the synthesis of two pyridinium-based room temperature protic ionic liquids (PILs), pyridinium bisulfate, [HPyr][HSO] and pyridinium sulphate, [HPyr][SO] and investigation of the kinetics of their water sorption behaviour and its influence on their density, ionic conductivity, and potential windows. The PILs were synthesized by the reaction of pyridine base with an acid, HSO, under solventless conditions, and confirmed by FTIR spectroscopy and 1H NMR spectra. The appearance vibration bands in the 3095-3252 cm range for -NH stretching in the FTIR spectra and a peak at a chemical shift of 8.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
October 2024
Department of Applied Chemistry, Graduate School of Science and Technology, Tokushima University, Tokushima 770-8506, Japan. Electronic address:
A capillary high-performance liquid chromatography (HPLC) system equipped with a dual-electrode detector utilizing track-etched membrane electrodes (TEMEs) was combined with a microdialysis sampling setup. The electrochemical detector benefits from the high electrolysis efficiency of TEMEs, allowing for calibration-free coulometric detection and simplifying data analysis to determine the dopamine recovery through a dialysis probe. Additionally, this system was used for in vivo monitoring of dopamine in the right striatum of a mouse brain.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2024
Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
Mixed ionic-electronic conductors are widely used as electroactive materials in energy applications. The contact of a mixed conductor with another phase plays a crucial role in charge storage and transport in energy devices. However, the interfacial chemistry at the heterojunctions comprising mixed conductors and its interplay with the bulk chemistry remains imperative yet inadequately understood.
View Article and Find Full Text PDFTalanta
December 2024
Palacký University, Faculty of Science, Department of Analytical Chemistry, 17. listopadu 1192/12, 771 46, Olomouc, Czech Republic.
The pungency of chili peppers, the most popular hot spice used worldwide, is caused by capsaicinoids (CPDs), the content of which can vary greatly due to varietal differences and growing conditions. For the first time, a novel simple method for the fast determination of CPDs in chili peppers and chili products was developed based on adsorptive transfer cyclic square-wave voltammetry (AdTCSWV), using adsorption of lipophilic CPDs on an unmodified glassy carbon electrode surface from methanolic extracts of chili pepper samples. The CSWV is based on short oxidation of adsorbed CPDs to quinoid products, and their subsequent reduction and re-oxidation to provide specific analytical signals with a linear range from 0.
View Article and Find Full Text PDFMikrochim Acta
February 2024
Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China.
An enzyme immunoassay was developed based on the coulometric measurement of immunoglobulin M (IgM) against Hantaan viruses (HTNV) by using virus-like particles (VLPs) as recognition molecules. The surface functionalization of screen-printed carbon electrodes (SPCEs) was achieved through paste-exfoliated graphene that was modified with a COOH group and a thionine mediator through supramolecular-covalent scaffolds, on SPCEs by using the binder contained in the ink. After the covalent immobilization of the antibody, the sensor was used for the sandwich enzyme immunoassay of IgM against HTNV.
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