Twenty-four-hour duplicate diet study 1994; nitrate and nitrite: method development and intake per person per day.

In spring and autumn of 1994 duplicates of 24-h diets were collected from 123 consumers (respondents). One goal of this study is to determine the amount of nitrite and nitrate in the duplicates of 24-h diets in order to establish the oral daily intake of these analytes. For this purpose a HPIC/UV method for the determination of nitrate and nitrite in duplicate diets was developed and validated. The mean intake of nitrate is 80 mg NO3- ion/person per day and the median intake of nitrite is 0.1 mg NO2- ion/person per day. The daily intake for nitrate as well nitrite is higher than found in the duplicate diets collected in the 1984/1985 study.