Сloud point extraction coupled with HPLC-UV for the determination of ibuprofen residues on stainless steel surface of pharmaceutical manufacturing equipment.

A new application of cloud point extraction coupled with HPLC-UV was developed for the determination of ibuprofen residues on stainless steel surface of pharmaceutical manufacturing equipment. Some parameters with an effect on the cloud point extraction of ibuprofen, such as the concentration of Triton X-114, pH influence, incubation time, equilibration temperature, and centrifuging parameters, were studied and optimized. For optimal cloud point extraction solution of Triton X-114 with concentration 0.

Lyophilic properties of surfactant-rich phases of polyethoxylated alkylphenols formed at cloud point temperature.

The influence of the concentration conditions, solutions acidity, and electrolyte additions on the lyophilic properties of the surfactant-rich phases of polyethoxylated alkylphenols OP-7 and OP-10 formed at cloud point temperature were studied. The lyophilic properties of surfactant-rich phases were determined by estimating of their effective hydration values and solvation free energy of methylene and carboxyl groups at cloud point extraction of aliphatic monocarboxylic acids. It was shown that the surfactant-rich phases formed from the dilute surfactant solutions have more hydrophobic properties than the phases formed from the high concentrated solutions.