Rapid and direct electrochemical determination of Ni(II) in industrial discharge water.

Industrial water contains a number of contaminants, such as organic pollutants and heavy metals, which can significantly affect the quality of soil, ground and environmental waters. We have successfully optimized and tested an electrochemical method and sensor modified with dimethylglyoxime for monitoring of nickel(II). The detection limit was 0.03mg/L and determination limit was 0.09mg/L. Linear concentration range was observed from 0.06 to 0.5mg/L Ni(II) and it is suitable for the analysis of environmental waters. The effect of all parameters important for on-site measurements (such as interferences, presence of dissolved oxygen, temperature) was investigated and considered in the analysis of mine discharge water. Water samples were analyzed without any pretreatment or filtration. A low level of error (5.6%) was observed for analysis demonstrating the usability of the optimized sensor and method for on-site measurements.

The binding of synthetic retinoids to lipocalin beta-lactoglobulins.

The binding of therapeutically relevant synthetic retinoid derivatives to bovine and reindeer beta-lactoglobulin (betaLG) is demonstrated using fluorescence quenching and ultrafiltration/HPLC methods. Furthermore, synthesis of methyl (E)-3-[4-[(E)-2-(2,6,6-trimethylcyclohex-1-enyl)vinyl]phenyl]-acrylate 4 and (E)-3-[4-[(E)-2-(2,6,6-trimethylcyclohex-1-enyl)vinyl]phenyl]acrylic acid 5 is described. All studied compounds bind to both betaLG homologues with nanomolar K(d) values, and the interaction diminishes the pH-dependent aggregation of retinoids. Thus, betaLG may show benefits in improving the bioavailability of retinoid derivatives.

Binding of phenolic compounds and their derivatives to bovine and reindeer beta-lactoglobulin.

In plant-based food, phenolic compounds usually do not exist in their native form, but as esters, glycosides, or polymers. The native forms, however, require deglycosylation for their intestinal absorption, and aglycone has been considered to be the potential health-protecting/promoting form. The binding of the aglycones of phenolic compounds to bovine and reindeer beta-lactoglobulins (betaLG) using fluorescence quenching was studied. The effects of pH and storage were also studied. Of the compounds investigated, the majority of flavones, flavonols, flavanones, and isoflavones were bound to betaLG. In the pH studies, no significant effects were found. The fact that the phenolic compounds were not released at pH 2 might indicate that they bind to an external part rather than to the central cavity. Studies implicated that betaLG could act as a binder or carrier for phenolic compounds in acidic, basic, or neutral conditions and that the ligand/betaLG complex can remain stable during storage.