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Abstract: Densities, conductivity, fluorescence and UV–vis absorption spectroscopy of glycyl dipeptide+ionic liquid (1-dodecyl-3-methylimidazolium bromide ([C12mim]Br))+water mixtures have been measured at different temperatures. From density data, the standard partial molar volume , standard partial molar volume of transfer for three glycyl dipeptides from water to aqueous [C12mim]Br solutions (Δt V o), partial molar expansibility and Hepler's constant have been calculated. Through the electrical conductivity measurements, the critical micellar concentration (c cmc) and a series of thermodynamic parameters of micellization of [C12mim]Br in aqueous glycyl dipeptide solutions are evaluated. Effects of temperature and hydrocarbon chain length of the glycyl dipeptides on the volumetric properties of dipeptides and critical micelle concentration (c cmc) of [C12mim]Br were examined. The pyrene fluorescence spectra were used to study the change of micropolarity produced by the interactions of [C12mim]Br with glycyl dipeptides, and the aggregation behavior of [C12mim]Br. From the results of UV–vis absorption spectra, the binding constant between dipeptide and [C12mim]Br above the c cmc was determined. [Copyright &y& Elsevier]

Highlights: [•] The values of and Δt V° are positive. [•] Interactions of Triton X-100 with charged and polar groups of dipeptides dominate. [•] Addition of dipeptide in water decreases the c cmc and the aggregation number of Triton X-100. [•] The affinity between dipeptide and Triton X-100 micelle increases with the increase in the length of alkyl chain of peptides. [•] Triton X-100 interacts with dipeptides more weakly than SDS. [ABSTRACT FROM AUTHOR]

A new aluminium (III) polymeric membrane electrode containing (E)-N′-(4-(dimetlylamino)benzylidene)-1H-benzo[d]midazobe-2-hydrazide (L) as a carrier has been prepared. The influence of membrane ingredients including ionophore, PVC, plasticizers and anionic excluders (NaTPB and KTpClPB) on the electrode response has been investigated. The best performance was obtained with a membrane composition of carrier L:DBP:PVC ratio of 1.00:65.99:33.01 (%, w/w). The sensor exhibited a Nernstian response for Al3+ ion ranging from 1.0×10−7 to 1.0×10−1 M with a detection limit of 5.6×10−8 M and a slope of 20.7mV/decade. It showed a relatively fast response time (10s), suitable reproducibility and stability, and good selectivity towards Al3+ ion. The prepared electrode was used as an indicator electrode in potentiometric titration of Al3+ with EDTA and in the determination of Al3+ ion in waste water and vermicelli. [ABSTRACT FROM AUTHOR]