Evaluation of mepiquat in malted barley and beer using LC-MS/MS

Abstract

Following recent studies that showed that the agrochemical mepiquat (1,1-dimethylpiperidinium) forms during the roasting of coffee beans and barley, this work investigates the presence of mepiquat in malted barley and commercially available beers. Liquid chromatography-tandem mass spectrometry was used to develop a sensitive and precise analytical method, with detection limits of 0.031 ng/g in malted barley and 0.014 ng/g in beer. Mepiquat was detected in nine out of 10 malted barley samples, with all results under the Canadian maximum residue limit (100 ng/g). The data suggest a relationship between perceived malted barley colour and mepiquat concentration. The concentration of mepiquat in the beers analysed was also below the maximum residue limits in Canada (100 ng/g) and in the EU (600 ng/g), suggesting that mepiquat is not a regulatory concern in finished beers.