A Polarographic Method for Bromide Residue Determination

Abstract

SUMMARY— A polarographic analytical procedure has been developed to give specific and quantitative responses based on the bromide content of food crops and other media. Improved extraction, ashing and oxidizing systems are used to improve recovery and reliability. The bromides present in plant material can be quantitatively removed with an aqueous‐alcohol solution, leaving the major portions of fats, protein and sugars undissolved. The ashing of the residue from this extract is simplified and allows larger samples to be processed. An absorption‐reaction train is used, first to oxidize the bromide to bromine and second from bromine to bromate. The bromate is measured for quantitation by polarography in a 1 M NH4OH/NH4CI solution. The polarogram is recorded using an applied voltage of −1 to −2 volts using the potential measured across the DME vs. a mercury pool. Application of this procedure has been made to 40 crops during the past three years. A mean recovery of 88.8 per cent has been calculated from fortified samples of every crop analyzed.

The occurrence of bromine in some Finnish and imported vegetables determined by a polarographic method

“…It has good sensitivity and specifity and is quickly performed (Beckman et al 1967). The modified polarographic technique used in the present experiments was found to be well suited for the purpose over a wide range of concentrations.…”

“…The bromine was determined polarographically according to a method developed by Beckman et al (1967). The cleaning-up procedure by which bromine was isolated and oxidized to bromate was adopted with only minor modifications.…”

“…On the other hand, high concentrations of bromine are found in lettuce and certain other vegetable grown on a soil fumigated with methyl bromide (Hoffmann andMalkomes 1974, Van Wambeke 1974). The purpose of this investigation was to determine the bromide contents of certain Finnish and imported vegetables, using a polarographic method developed by Beckman et al (1967) and modified by the authors.…”

Simplified Conversion of a Direct-Current Polarograph to a Low Frequency, Alternating-Current Instrument.

“…Physik 64, 547 (1930). (2) ttihe alternating current polaro--L graphic method described in this article is limited only to the use of low frequency (60 c.p.s. ), constant a.c. voltage of a relatively small value.…”