[Studies on the contents of nitrates and nitrites in selected fresh and heat processed vegetables].

The levels of nitrates and nitrites were determined in fresh vegetables and the same products subjected to culinary processing such as boiling. Nitrates were reduced on a cadmium column to nitrites, where upon they were determined colorimetrically using sulfanilic acid and N-1-naphthyl-ethylenediamine. Thermal processing of these vegetables reduced the level of nitrates by about 50% and the nitrites loss reached even 100%.

[Content estimation of nitrates and nitrites in vegetables from the province of Lodz].

The contents of nitrates and nitrites in selected vegetables reaped in summer and autumn in 1993 were investigated. The samples of vegetables were collected directly from the producers from area of Lódź and from outside of the city. Nitrates were reduced on a cadmium column to nitrites, where-upon they were determined colorimetrically using sulfanilic acid and N-1-Naphthylethylenediamine.