Figure 6

Evaluation of the optimal enzyme ratio (3.05 mm graphite electrodes, -50 mV vs. Ag/AgCl). 1 μL HRP/1 μL of cell suspension - (■), 1.5 μL HRP/1 μL of cell suspension - (●), 2 μL HRP/1 μL of cell suspension - (▲). HRP and cell suspension were entrapped behind the dialysis membrane (cut off 10 kDa). Testing solution: 30 mM Tris-HCl (pH 8.9); working volume: 20 mL; stock solution of uric acid: 10 mM in 30 mM Tris-HCl (pH 8.9).