A new application of bromopyrogallol red as a selective and sensitive competition assay for recognition and determination of acetate anion in DMSO/water media

Bromopyrogallol red, BPR, (2-(2,7-dibromo-4,5,6-trihydroxy-3-oxo-3H-xanthen-9-yl) benzenesulphonic acid, Scheme 1) as a new chromogenic anion receptor, can selectively and efficiently be applied for detection of AcO− over wide range of anions such as BzO−, F−, Cl−, Br−, OH−, I−, NO3−, HSO4−, CN− and CO32− in mixed DMSO/H2O media. Increasing the amount of H2O up to 50% (v/v) caused a dramatic development in selectivity of AcO−. The developed BPR enabled the determination of acetate in the linear concentration range of 19.0–42.0 μM (1.12–24.8 μg mL−1) with the detection limit of 2.5 μM (0.147 μg mL−1) and the relative standard deviation (RSD, C = 19.4 μM, n = 5) of less than 1%. This enables the design and development of reusable optical receptors for monitoring trace amounts of acetate ion in vinegar samples and the values agreed with those mentioned by the manufacturers.

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► The ability to apply this receptor in the presence of water.
► The great selectivity toward AcO− over F− and BzO− which are usual interferences.
►  The simplicity of the BPR, which allows so-called “naked-eye” detection.
► Successful detection and determination of acetate in real samples.
►  Availability of pure BPR.