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The aim of this study was to introduce a novel, simple, and highly sensitive preparation method for determination of tylosin in different milk samples. In the so-called functionalized TiO2 hollow fiber solid/liquid-phase microextraction method, the acceptor phase is functionalized TiO2 nanoparticles that are dispersed in the organic solvent and held in the pores and lumen of a porous polypropylene hollow fiber membrane. An effective functionalization of TiO2 nanoparticles has been done in the presence of aqueous H2 O2 and a mild acidic ambient under UV irradiation. This novel extraction method showed excellent extraction efficiency and a high enrichment factor (540.2) in comparison with conventional hollow fiber liquid-phase microextraction. All the experiments were monitored at λmax = 284 nm using a simple double beam UV-visible spectrophotometer. A Taguchi orthogonal array experimental design with an OA16 (4(5) ) matrix was employed to optimize the factors affecting the efficiency of hollow fiber solid/liquid-phase microextraction such as pH, stirring rate, salt addition, extraction time, and the volume of donor phase. This developed method was successfully applied for the separation and determination of tylosin in milk samples with a linear concentration range of 0.51-7000 μg/L (r(2) = 0.991) and 0.21 μg/L as the limit of detection.

The adsorption of C.I. Basic Yellow 2 (BY2) from aqueous solutions on to hardened paste of Portland cement (HPPC) as a low-cost adsorbent and its adsorption kinetics at different conditions were studied. The adsorption process was followed by an online spectrophotometric analysis system, which consisted of a UV-Vis spectrophotometer, a designed spectrophotometric cell, a peristaltic pump and a glass reactor. The effect of experimental parameters, including initial dye concentration, mass of HPPC, initial pH and temperature, on adsorption was studied over a 30 miin adsorption period. For the kinetic study, the obtained data were treated according to various kinetic models. The results revealed that the experimental data were better fitted to the first-order kinetics model than to the second-order and intraparticle diffusion models. Equilibrium isotherms for the adsorption of BY2 on HPPC were analysed by Freundlich and Langmuir isotherms equations using the linear correlation coefficient. The Freundlich isotherm gave the best correlation of adsorption.

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