A dynamic gas extraction-assisted paper-based method for colorimetric determination of bromides†
A new method for selective determination of bromides in natural waters, foodstuffs and pharmaceuticals has been developed. It is based on oxidation of bromides with dichromate, dynamic gas extraction of molecular bromine with an air flow and sensing by paper modified with silver triangular nanoplates (AgTNPs) as a colorimetric reagent. Interaction of AgTNPs with bromine resulted in the discoloration of the AgTNP-modified paper, which was monitored using a scanner. The high selectivity of the dynamic gas extraction for volatile bromine enabled the direct determination of bromides in mineral water, river and sea water, alga, shrimps, fish, bread and pharmaceuticals with minimal sample pretreatment. The limit of detection of bromide was found to be 0.02 mg L−1. The determination range was 0.05–1.5 mg L−1.