PL
Oznaczono zawartość azotanów(V) oraz azotanów(III) w 10 warzywach pochodzących z upraw ekologicznych i konwencjonalnych. Przeprowadzone badania wykazały znacząco wyższą zawartość azotanów(V) w warzywach z upraw konwencjonalnych - ziemniakach, kapuście białej i pekińskiej oraz selerze. Oznaczane zawartości azotanów(V) w obu badanych grupach, za wyjątkiem pomidorów, marchwi oraz sałaty z upraw ekologicznych przekraczały wartości dopuszczone limitami. Zawartość azotanów(III) w warzywach konwencjonalnych, jak i ekologicznych była poniżej wartości 0,5 mg NO2-/kg.
EN
Nitrates and nitrites content in ten selected vegetables from conventional and ecological farms was estimated. Vegetables were bought in late June and in July. 2003 in seven shops or supermarkets selling conventionally grown crops, and in seven special shops offering certified, organically grown vegetables. The content of nitrates and nitrites was determined by high performance liquid chromatography (a Gilson HPLC apparatus with a Supelco analytical column and guard column) after prior protein precipitation by Carrez solution. The mobile phase consisted of acetonitrile and 0.05 M KH2PO4 (at 20:80 ratio). The flow rate was 1.5 cm3/min. Peaks were measured at 214 nm. Results were reported in mg/kg fresh weight as mean ± SD and compared to the admissible limits. Significantly higher levels of nitrates was found in conventionally grown vegetables, such as potatoes, china cabbage, white cabbage and celery. Amounts of nitrates in both groups of vegetables (except for tomato, carrot and lettuce from the ecological farming) exceed the admissible limit values. Nitrites content of the conventional- and organic-grown vegetables was below 0.5 mg NO2-/kg