Electrochemical oligonucleotide-based biosensor for the determination of lead ion.

The possibility of utilization of gold electrodes modified with short guanine-rich ssDNA probes for determination of Pb(2+) was examined. Interaction between guanine residues and lead ion followed by formation of G-quadruplex structures was confirmed by electrochemical impedance spectroscopy investigations. An external cationic redox label, methylene blue, was employed in voltammetric measurements for analytical signal generation.

[Calcium in the diet of selected groups of people].

Calcium-content was determined in 23,557 daily food rations of the individuals fed individually or in sets of food or meals prepared in various institutions (3,298) in 1975-1987. Calcium deficit in daily food of girls and adult women has ranged from 50% to 6.2% in comparison with daily intakes recommended in Poland.

[Nitrates and nitrites in the environment and their effect on human health].

The review was made on the major sources of human exposure to nitrates and nitrites, metabolism of these chemicals and their content in different body fluids. The health consequences of ingestion of nitrates and nitrites were presented. The methods of determination of nitrates, nitrites and nitrosamines were discussed.