[Comparison of various technics for determining nitrates in soil and vegetables].

In order to compare results obtained from various analytical techniques, nitrate determinations in soils and vegetables were made by four usual methods. These are a selective electrode, an autoanalyser with dialyser that determines nitrites following a nitrate reduction step by hydrazine sulfate, another autoanalyser that reduces nitrates with cadmium metal, and the usual DEVARDA method. Interferences and limitations of these techniques are discussed.