The properties of 3 binary mixtures containing piperazine were investigated in this work. In a first step, the densities for the two binary mixtures (piperazine + methanol) and (piperazine + acetone) were measured in the temperature range of 293.15 to 328.15 K and 293.15 to 323.15 K, respectively, at atmospheric pressure by using a Rudolph research analytical density meter (DDM 2911). The concentration of piperazine in the (piperazine + methanol) mixture was varied from 0.6978 to 14.007 mol/kg, and the concentration of piperazine in the (piperazine + acetone) mixture was varied from 0.3478 to 1.8834 mol/kg. On the other hand, the density data for the (piperazine + water) mixture were taken from the literature in the temperature range of 298.15 to 328.15 K. In a second step, for the 3 investigated systems, the apparent molar volume (Vϕ) and the limiting apparent molar volume (Vϕ0) at infinite dilution were calculated using the Redlich–Mayer equation. The limiting apparent molar volumes (Vϕ0) were used to study the influence of the solute-solvent and solute-solute interactions. The temperature dependency of the apparent molar volumes was used to estimate the apparent molar expansibility, Hepler’s constant ∂2Vϕ0/∂T2P, and isobaric thermal expansion coefficients αP.

No abstract

The present study was conducted to evaluate the risk associated to human health by heavy metals through the intake of beverages (fruit juices, soft and energy drinks) excessively used in city Lahore, Pakistan. The concentration in ppm of heavy metals (Pb, Cr, Co, Cd, Zn and Ni) in 17 popular beverages has been investigated by using Flame Atomic Absorption Spectrophotometer (AAnalyst 400-PerkinElmer). A range of standard solutions were prepared according to the standard methods governed by American Public Health Association. It has been observed that concentration of some heavy metals (i.e Pb, Cr, Co, Zn and Ni) in all collected samples (i.e 17) were found close to the Standard permissible limits provided by World Health Organization, United Sates Environmental Protection Agency, and Pakistan Standards Quality Control Authority. However, all samples were free from any detectable concentration levels of Cd.