Determination of manganese with Methylene Blue in various vegetable crops

H.P. Beck, D. Kostova and B. Zhang

Inst. Inorg. Anal. Chem. Radiochem.,Saarland Univ. Saarbrucken, D-66123, Germany

Abstract:

A study was made of the manganese content in the crop production of 28 vegetable species, using the most common cultivars within the species. The manganese content was determined by a new extraction – spectrophotometric method using Methylene Blue (MB). The ion – associate of Mn(VII) was completely removed in a single extraction of only 5 s, and the 1,2-dichloroethane layer remained constant for 2 days under the usual laboratory conditions. To compare results, manganese was determined by the atomic – absorption method. The results obtained showed that the manganese content varies significantly in the different vegetable species and cultivars. The manganese content in more widely used varieties of tomatoes, peppers, head cabbage, melons, and radishes was studied in order to establish differences with respect to the level of this element in their production.

Key words:

Alliaceae, Apiacea, Brassicaceae, Cucurbitaceae, extraction – spectrophotometry, Fabaceae, Lamiacea, manganese determination, plants, Solanaceae