Efficient concentrations antioxidant extraction

With low detection limit techniques, the identity, migration levels and accumulation of antioxidants and their degradation products in food, in hquids and in pharmaceutical solutions can be controlled. HPLC or GC-MS offers functional methods together with, e.g., hquid-liquid extraction (LLE). Recently, solid phase extraction (SPE) has been used successfully with lower detection hmits and smaller errors than LLE. SPE is a technique that uses a small amount of solvent and that efficiently concentrates solutions of analytes depending on, e.g., polarity. 

In the present work an attempt has been made to optimize the parameters related to the extraction of antioxidants (with ASE) from Spirulina platensis using only environmentally clean solvents such as water, ethanol and mixtures. Thus, as a first approach, a study about different sample pre-treatments and how these affect both, the extraction yield and the final antioxidant activity has been performed. Moreover, a relationship between the efficient concentration (ECso) and the final composition of the solvent (as a function of the dielectric constant) has been studied and a preliminary characterization of the chemical composition of one of the best antioxidant extract has been done using an optimised CE-DAD method. 

Macromolecular stabilizers are immobile in the polymer matrix [284], This is unfavourable for applications where surface concentration of stabilizers in thick-walled products should remain high. It was reported [34] that rubber-bound derivatives of PD provide only very poor antiozonant protection. Their antioxidant efficiency was only comparable with that of conventional HMW PD. This indicates that application of polymer-bound amines in rubbers has the prospect of exclusive long-term use in extracting media. 

To add extra value to discarded chicken carcasses and utilize them, efficiency of a membrane process for purification and concentration of antioxidative dipeptides contained in chicken extract was investigated. 

The majority of the indirect methods used for the analysis of antioxidants in plastic materials utilize some type of extraction process in order to separate the additive from the polymer matrix. Once the desired analyte has been extracted, its concentration level can be readily determined by a variety of techniques. The goal of any extraction technique is to obtain an extraction efficiency for the analyte which meets the analytical requirements in the shortest time possible. The extraction process should be selective so that only the analytes of interest are removed from the polymer. In addition, the actual extraction step should not degrade, modify or adulterate the additives in any way. 

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