Copper determination in beer by flame atomic absorption spectrometry after extraction and preconcentration by dispersive liquid–liquid microextraction

•A simple extraction and preconcentration method was proposed for Cu determination in beer samples.•The single vessel principle was applied combined with a low-cost detection technique.•Low reagent amounts were required for Cu extraction and determination by FAAS.•The LOD/LOQ values by DLLME/FAAS were fit for purpose and lower than the obtained by MAD/ICP-MS and MAD/ICP-OES.•Results by DLLME/FAAS were in agreement with those after beer digestion and determination by ICP-MS and ICP-OES.