Synthesis, Kinetic Study, and Spectroscopic Analysis of Peroxidase-like Pinch-Porphyrin Fe(III) Complexes.

In the present manuscript, we report the kinetic and spectroscopic analysis of six new pinch-porphyrins: protoporphyrin-picpenta , mesoporphyrin-picpenta , deuteroporphyrin-picpenta , protoporphyrin-picocta , mesoporphyrin-picocta , and deuteroporphyrin-picocta . The Michaelis-Menten enzymatic pathway and the guaiacol test confirmed the ability of the compounds to function like new peroxidase models. UV-vis, H NMR, and electron spin resonance studies are in accordance with porphyrin-Fe(III) molecules with the quantum phenomena called quantum mixed spin (qms, = 3/2, = 5/2).

Spectroscopic and Kinetic Characterization of Peroxidase-Like π-Cation Radical Pinch-Porphyrin-Iron(III) Reaction Intermediate Models of Peroxidase Enzymes.

The spectroscopic and kinetic characterization of two intermediates from the H₂O₂ oxidation of three dimethyl ester [(proto), (meso), (deuteroporphyrinato) (picdien)]Fe(III) complexes ([FePPPic], [FeMPPic] and [FeDPPic], respectively) pinch-porphyrin peroxidase enzyme models, with s = 5/2 and 3/2 Fe(III) quantum mixed spin (qms) ground states is described herein. The kinetic study by UV/Vis at λmax = 465 nm showed two different types of kinetics during the oxidation process in the guaiacol test for peroxidases (1-3 + guaiacol + H₂O₂ → oxidation guaiacol products). The first intermediate was observed during the first 24 s of the reaction.

Determination of moderately polar arsenolipids and mercury speciation in freshwater fish of the River Elbe (Saxony, Germany).

Arsenic and mercury are frequent contaminants in the environment and care must be taken to limit their entrance into the food chain. The toxicity of both elements strongly depends upon their speciation. Total amounts of As and Hg as well as their species were analyzed in muscle and liver of 26 fishes of seven freshwater fish species caught in the River Elbe.

Mass spectrometric detection, identification, and fragmentation of arseno-phytochelatins.

Phytochelatins (PC) are cystein-rich oligopeptides in plants for coordination with toxic metals and metalloids via their thiol groups. The composition, structure, and mass spectrometric fragmentation of arseno-PC (As-PC) with PC of different degree of oligomerization (PC2-PC5) in solution were studied using liquid chromatography coupled in parallel to inductively coupled plasma mass spectrometry and electrospray ionization quadrupole time-of-flight mass spectrometry. As-PC were detected from As(PC2) to As(PC5) with an increasing number of isomers that differ in the position of thiol groups bound to As.

Species determination of Culicoides biting midges via peptide profiling using matrix-assisted laser desorption ionization mass spectrometry.

Background: Culicoides biting midges are vectors of bluetongue and Schmallenberg viruses that inflict large-scale disease epidemics in ruminant livestock in Europe. Methods based on morphological characteristics and sequencing of genetic markers are most commonly employed to differentiate Culicoides to species level. Proteomic methods, however, are also increasingly being used as an alternative method of identification.

Determination and identification of hydrophilic and hydrophobic arsenic species in methanol extract of fresh cod liver by RP-HPLC with simultaneous ICP-MS and ESI-Q-TOF-MS detection.

The present study was focused on the determination and identification of arsenic species in methanolic extracts of cod liver. Arsenic species were fractionated and the fractions analysed by RP-HPLC-ICP-MS coupled with ESI-Q-TOF-MS. The total concentration of arsenic in the fresh cod liver was analysed by ICP-MS to be 1.

Different strategies of cadmium detoxification in the submerged macrophyte Ceratophyllum demersum L.

The heavy metal cadmium (Cd) is highly toxic to plants. To understand the mechanisms of tolerance and resistance to Cd, we treated the rootless, submerged macrophyte Ceratophyllum demersum L. with sub-micromolar concentrations of Cd under environmentally relevant conditions.

Identification of degradation products of phenylarsonic acid and o-arsanilic acid in contact with suspensions of soils of volcanic origin.

A set of organoarsenicals were identified in aqueous phenylarsonic acid (PA) and o-arsanilic acid (AA) solutions treated with soil of volcanic origin in batch systems. The transformation products were separated by liquid chromatography (RP-LC) and identified with element selective inductively coupled plasma-mass spectrometry (ICP-MS) as well as molecular selective electrospray ionization-mass spectrometry (ESI-MS) detection after their HPLC separation. The identification of the main degradation products by means of ESI-MS, ESI-MS/MS and ESI-TOF-MS showed the occurrence of nitrophenylarsonic acid and methylphenylarsinic acid in the solutions containing AA and PA in contact with soils, respectively.

Formation of sulfonyl aromatic alcohols by electrolysis of a bisazo reactive dye.

Five sulfonyl aromatic alcohols, namely 4-((2-hydroxyethyl)sulfonyl)phenol, 4-((2-(2-((4-hydroxyphenyl)sulfonyl)ethoxy)vinyl)sulfonyl)phenol, 4-(ethylsulfonyl)phenol, 4-(vinylsulfonyl)phenol and 5-((4-aminophenyl)sulfonyl)-2-penten-1-ol were identified by LC-ESI-Qq-TOF-MS as products formed by electrolysis of the bisazo reactive dye Reactive Black 5 (RB5). Since electrolyses were performed in an undivided cell equipped with Ni electrodes in alkaline medium, amines like 4-(2-methoxyethylsulfonyl)benzene-amine (MEBA) with m/z 216 were also suspected to be formed due to the plausible chemical reaction in the bulk or the cathodic reduction of RB5 and its oxidation by-products. Aiming to check this hypothesis, a method was used for the preparation of MEBA with 98% purity, via chemical reduction also of the dye RB5.

Retention of phenylarsenicals in soils derived from volcanic materials.

Sorption of phenylarsenicals including 4-hydroxy-3-nitrophenylarsonic acid (roxarsone), an animal feed additive widely used for growth stimulation, on soils was investigated in batch systems. Phenylarsonic acid, o-arsanilic acid and roxarsone were retained differently by unpolluted, non-sterilized soils. Sorption isotherms were analyzed by the Henry, Tóth and Langmuir-Freundlich equations.