A three-dimensional composite film-modified electrode based on polyoxometalates and ionic liquid-decorated carbon nanotubes for the determination of L-tyrosine in food.

A stable and innovative composite film-modified electrode based on Dawson polyoxometalates H 8 P 2 Mo 16 V 2 O 62 (P 2 Mo 16 V 2 ) and ionic liquid (BMIMBr)-decorated carbon nanotubes, annotated as PEI/(P 2 Mo 16 V 2 /BMIMBr-CNTs) 8 , has been constructed by using the layer-by-layer self-assembly (LBL) method for the determination of L-tyrosine. The combination of three active components not only offers higher conductivity to facilitate rapid electron transfer, but also avoids the accumulation of P 2 Mo 16 V 2 to expand the contact area and increase the reactive active sites. The modified electrode exhibits outstanding sensing performance for determination of Tyr with wide linear determination range of 5.8×10 -7 M ~ 1.2×10 -4 M, low determination limit of 1.7×10 -7 M (S/N=3), high selectivity for common interferences, and excellent stability at the potential of +0.78 V (vs. Ag/AgCl (3 M KCl)). The relative standard deviation (RSD) of 4.3% for five groups of parallel experiments shows the satisfactory repeatability of PEI/(P 2 Mo 16 V 2 /BMIMBr-CNTs) 8 . In addition, for determination of Tyr, the PEI/(P 2 Mo 16 V 2 /BMIMBr-CNTs) 8 shows good recoveries of 98.8-99.8% in meat floss, which can be feasible in practical application.