This paper describes the development of a new method for the quantification of bumetanide in urine samples from athletes and in pharmaceutical formulations to detect doping, using a biomimetic sensor based on a biomimetic catalyst of the P450 enzyme.

Metribuzin is a widely used pesticide with a half-life of up to 2 months and high affinity to organic matter that should be carefully monitored. Here is reported the development of a modified carbon paste electrode using cobalt phthalocyanine as a biomimetic catalyst for the determination of metribuzin. The diffusion coefficient of metribuzin at room temperature was (59 � 16) � 10 −6 cm 2 s −1 and the apparent Michaelis-Menten constant (K ap M) was (7.4 � 0.6) � 10 −6 mol L −1. Electroanalytical measurements were performed by amperometry and the following figures of merit were obtained: limit of detection of 5.3 � 10 −6 mol L −1 (1.14 mg L −1), linear range up to 2.0 � 10 −4 mol L −1 , recoveries above 93% (performed on spiked water samples), interday repeatability of 4.5% and intraday repeatability of 3.5%, and suitable selectivity.