Lakhasly

Preparation of beer samples

Samples were prepared following a protocol from a previous stApparatus

SPCE systems, with graphite as working and counter elec- trode and Ag/AgCl as a reference electrode, were manufactured

Washing

V2

Buffer Substrate

Cavro

Waste

XLP 6000

1161

using a DEK 248 screen-printing system according to a proce- dure previously described [26] in a three-electrode configuration.The working electrode was a 4-mm diameter disk, the auxiliary electrode was 16mm x 1.5 mm curved line and the Ag/AgCl pseudo-reference electrode was a 5mmx 1.5 mm straight line.

Preparation of beer samples

Samples were prepared following a protocol from a previous stApparatus

SPCE systems, with graphite as working and counter elec- trode and Ag/AgCl as a reference electrode, were manufactured

Washing

V2

Buffer Substrate

Cavro

Waste

XLP 6000

1161

using a DEK 248 screen-printing system according to a proce- dure previously described [26] in a three-electrode configuration. The working electrode was a 4-mm diameter disk, the auxiliary electrode was 16mm x 1.5 mm curved line and the Ag/AgCl pseudo-reference electrode was a 5mmx 1.5 mm straight line. Autolab PGSTAT12 2 potentiostat (Metrohm, France) was used for the pretreatment of SPCE electrodes. Thermocycler mastercycler personal from Eppendorf (Le Pecq, France) was used for pre- heat treatment tof the aptamer. Magnetic beads were mixed by HulaMixer sample mixer from Invitrogen (USA). HPLC equipment consisted of an L-7110 LaChrom Hitachi pump (Merck, Germany) and an L-2485 Elite LaChrom Hitachi fluorescence detector (VWR, France). The HPLC Kinetex 2.6 mmC18 100A, 100 mm x 4.60 mm column was obtained from Phenomenex (USAudy (27). the spiked beer was passed through a filter (0.45 mm). The beer samples were spiked with the known con- centration of stock solution of OTA.