Peroxyoxalate chemiluminescence in aqueous solutions: coupling of immobilized enzyme reactors and 1,1'-oxalyldiimidazole chemiluminescence reaction to flow-injection analysis and liquid chromatographic systems.

A highly sensitive method for the determination of enzymatically generated hydrogen peroxide in flow-injection analysis (FIA) and liquid chromatography (LC) has been developed. A dual-line flow system is used, one carrier (or eluent) delivering the analyte and the other one the chemiluminescent reagent 1,1'-oxalyldiimidazole (ODI). The results show that the composition of the analyte flow line is not critical for the chemiluminescence detection step; even purely aqueous buffers, as generally applied if immobilized enzyme reactors (IMERs) are involved in FIA and LC, can be used without loss of sensitivity. IMERs containing either glucose oxidase or acetylcholine esterase/choline oxidase were incorporated in this flow line and favourable detection limits (S/N = 3) were obtained, i.e. 3 nM for glucose and 50 nM for acetylcholine and choline. The performance of the approach in real-sample analysis was tested by determining glucose and choline in urine samples

A phosphotyrosine-imprinted polymer receptor for the recognition of tyrosine-phosphorylated peptides.

Synthesis of a molecularly imprinted polymer (MIP) for selective SPE extraction of peptides hyperphosphorylated at tyrosine. Proof of concept is presented by using HPLC and microLC on models such as phosphorylated angiotensin II in the presence of an excess of its non-phosphorylated counterpart. This approach appears suited for targeting disease biomarkers. One of the first MIPs capable to recognize peptides or protein epitopes thus advocating the usage for the recognition of biotechnological drugs. Sintesi di un materiale per estrazione in fase solida (SPE) altamente specifico per l’analisi qualitativa (riconoscimento) di peptidi iperfosforilati alla tirosina. Verifica mediante HPLC e microLC su modelli quali l’angiotensina II fosforilata e non fosforilata. Applicazione per l’analisi qualitativa di sostanze aventi attività biologica o tossicologica e per la diagnostica di patologie tumorali. Uno dei primi esempi di MIPs in grado di riconoscere peptidi o epitopi di proteine, preconizza l’impiego per il riconoscimento di farmaci biotecnologici

Chromatographic comparison of bupivacaine imprinted polymers prepared in different formats: crushed monolith, microsphere, silica-based composite and capillary monolith formats

A comprehensive comparison of five chromatographic stationary phases based on molecularly imprinted polymers is presented. Efficiency, imprinting factors, water compatibility and batch-to-batch reproducibility are discussed for crushed monolith, microspheres, two silica-based composites and capillary monoliths, all imprinted with the local anaesthetic bupivacaine. Synthesis protocol and chromatographic test conditions have been kept fixed within certain limits, in order to provide further insight into the strengths and weaknesses of the different formats. Excluding microparticles, all formats give satisfactory performance, especially in aqueous mobile phases. An assessment of batch-to-batch reproducibility in different mobile phases adds further value to this comparison study

First intercomparison study on the analysis of oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) and nitrogen heterocyclic polycyclic aromatic compounds (N-PACs) in contaminated soil

Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) and nitrogen heterocyclic polycyclic aromatic compounds (N-PACs) are toxic, highly leachable and often abundant at sites that are also contaminated with PAHs. However, due to lack of regulations and standardized methods for their analysis, they are seldom included in monitoring and risk-assessment programs. This intercomparison study constitutes an important step in the harmonization of the analytical methods currently used, and may also be considered a first step towards the certification of reference materials for these compounds. The results showed that the participants were able to determine oxy-PAHs with accuracy similar to PAHs, with average determined mass fractions agreeing well with the known levels in a spiked soil and acceptable inter- and intra-laboratory precisions for all soils analyzed. For the N-PACs, the results were less satisfactory, and have to be improved by using analytical methods more specifically optimized for these compounds.JRC.D.2-Standards for Innovation and sustainable Developmen