Migration analysis of Cr, Ni, Al, Fe, Mn, Cu, Zn, and Mo in internet-bought food serving stainless-steel utensils by ICP-MS and XRF

A total of 120 internet bought stainless-steel utensil samples intended for food serving were analysed for their release of Cr, Ni, Al, Fe, Mn, Cu, Zn, and Mo. Samples were extracted using simulants under continuous and discontinuous test conditions, extracts were analysed by ICP-MS, and metallic compositions of utensils were indicated by XRF analysis. r² values for all analytes were determined between 0.9982 and 0.9997. RSD and WRm values ranged between 4.5-8.5% and 80-107% for all analytes, respectively, and LOD was in the range of 0.11-25.8 µg/l. Migration results show that 35% of total sample types show non-compliance with the SMLs established by the Nordic guidelines. XRF data show good correlation between the metals' migration levels and their respective compositions in the utensil, and toxicological exposure estimates no significant adverse health effects from food served with articles exceeding the SMLs for Fe, Al, and Ni.

Asymmetric Three-Component Heck Arylation/Amination of Nonconjugated Cyclodienes

Substituted cyclohexylamines are becoming increasingly important in drug discovery. Asymmetric Heck insertion/amination of nonconjugated cyclodienes proceeds to give 5-aryl cyclohexenylamines with good enantioselectivity and exclusive trans configurations. Primary and secondary anilines, indoline, and benzylamines are suitable amines. The weakly donating diphosphite Kelliphite forms a deep unsymmetrical pocket, which is essential for stereoselective anti attack of amines.

Highly Stereoselective Synthesis of 1,3-Dienes through an Aryl to Vinyl 1,4-Palladium Migration/Heck Sequence

An efficient aryl to vinyl 1,4-palladium migration/Heck sequence was developed for the stereoselective synthesis of 1,3-dienes. High stereoselectivity was observed not only for 1,3-dienes bearing two similar aryl groups at terminal positions, but also for those with configurations shown to be unfavorable with previous methods.

Effect of electro-activated brine solution on the migration of metallic ions from the cans to the product in sterilized canned sweet corn

Tinplate cans were used to study if electro‐activated brine solution (EAS) is more corrosive than conventional one by ICP analysis. The results showed different effects of EAS on cans, alone or filled with product. Acidic EAS (pH 2–3) and Redox +900 to +1200 mV highly reacted with the cans. The concentrations of Zn, Fe, and Cu in the solution were 0.028, 28.81, and 0.022 ppm, respectively. No Sn migration was observed in this case. When neutral or acidic chlorine‐free EAS was used, no significant difference was observed in comparison with the corrosivity of standard NaCl brine. Alkaline EAS with pH>10 and negative E (≤−966 mV) did not affect Zn, Fe, and Cu migration. However, it affected tin migration. Nevertheless, it is important to mention that even if some corrosion was observed, it was in the limit of the permitted level of concentration when the cans were filled with a product.

Electrochemically induced surface metal migration in well-defined core-shell nanoparticles and its general influence on electrocatalytic reactions

Bimetallic nanoparticle catalysts provide enhanced activity, as combining metals allows tuning of electronic and geometric structure, but the enhancement may vary during the reaction because the nanoparticles can undergo metal migration under catalytic reaction conditions. Using cyclic voltammetry to track the surface composition over time, we carried out a detailed study of metal migration in a well-defined model Au-Pd core-shell nanocatalyst. When subjected to electrochemical conditions, Au migration from the core to the shell was observed. The effect of Pd shell thickness and electrolyte identity on the extent of migration was studied. Migration of metals during catalytic ethanol oxidation was found to alter the particle's surface composition and electronic structure, enhancing the core-shell particles' activity. We show that metal migration in core-shell nanoparticles is a phenomenon common to numerous electrochemical systems and must be considered when studying electrochemical catalysis.