Simultaneous electrochemical detection of tryptophan and tyrosine using boron-doped diamond and diamond nanowire electrodes

•Detection of tryptophan/tyrosine with boron-doped diamond electrodes and nanowires.•Simultaneous detection of amino acids in mixtures with tryptophan/tyrosine ≤ 0.5.•Nanowires allow detection limits of 0.5 μM and 0.2 μM for tryptophan and tyrosine.•Tyrosine and tryptophan were simultaneously detected in spiked human serum.

The simultaneous detection of tryptophan and tyrosine by electrochemical means is not trivial as both amino acids display comparable oxidation potentials. Here, we show that simultaneous detection of both amino acids can be achieved on boron-doped diamond (BDD) electrodes and wires when the ratio of tryptophan/tyrosine is ≤ 0.5. The possibility to detect quantitatively tryptophan and tyrosine in human blood serum samples was investigated.