Role of surfactant headgroups on the toxicity of SLES-LAS mixed micelles: A case study using microtox test.

Mixtures containing ether sulfate based surfactants (SLES) and linear alkylbenzene sulfonic acid (LAS) are relatively common in personal care and household products. When in mixture, they form mixed micelles, which act as reservoirs for the cleaning process. The increase of ethylene oxide (EO) units in the head of SLES lowers the critical micelle concentration, meaning that less quantity of each surfactant is needed to form the micelles.

NMR, DFT and luminescence studies of the complexation of Zn(II) with 8-hydroxyquinoline-5-sulfonate.

Multinuclear ((1)H, (13)C) magnetic resonance spectroscopy, DFT calculations and luminescence techniques have been used to study 8-hydroxyquinoline-5-sulfonate (8-HQS) and its complexes with Zn(ii), in aqueous solution. The study combines the high sensitivity of luminescence techniques, the selectivity of multinuclear NMR spectroscopy with the structural details accessible through DFT calculations, and aims to obtain a detailed understanding of the complexation between the Zn(2+) ion and 8-HQS. In addition to a complete assignment of the (1)H and (13)C NMR signals of 8-HQS, a full speciation study has been performed.