Headspace single drop microextraction based visual colorimetry for highly sensitive, selective and matrix interference-resistant determination of sulfur dioxide in food samples

•A sensitive, selective and matrixinterference-resistant SO2 analytical method.•A miniaturized and portable device for detection of SO2 in food samples.•A simple TMB-based visual colorimetry that could be easily read out by naked eye.•A low-cost and efficient combination of single drop and headspace microextraction.