A cost-saving preparation of nickel nanoparticles/nitrogen-carbon nanohybrid as effective advanced electrode materials for highly sensitive tryptophan sensor

Preparation of the Ni NPs/N-C nanohybrid and construction processes of the proposed Ni NPs/N-C/CPE-based electrochemical Trp sensor. [Display omitted] •Cost-saving preparation of Ni NPs/N-C was simply prepared as advanced electrode materials.•Electrochemical sensor for tryptophan detection by Ni NPs/N-C/CPE was fabricated.•The sensor shows high electrochemical performance and good sensitivity for Trp.•Low-cost, high stability and repeatability of Ni NPs/N-C/CPE were witnessed. Here we report a facile and cost-effective preparation of nickel nanoparticle S/Nitrogen-carbon nanohybrid (Ni NPS/N-C) based on formamide condensation and carbonization, used for highly sensitive and selective electrochemical determination of tryptophan (Trp) in practical samples. The crystallographic phase, surface morphology, elemental distribution, and chemical state of the Ni NPS/N-C nanohybrid were analyzed by XRD, SEM, TEM, EDS, XPS, FTIR, TGA and Raman spectra. The results show that high content of Ni NPs (6.62 wt%) were distributed in the nanohybrid, and a large number of bamboo-like nanotubes were formed during pyrolysis, which dramatically increases the specific surface area, and remarkably promotes the electrical conductivity as well as the catalytic activity of the nanohybrid. The electrochemical behavior of Trp was investigated on the nanohybrid modified carbon paste electrode (Ni NPS/N-C/CPE) and the measurement parameters were optimized. As expected, the modified electrode can remarkably enhance the electrochemical oxidation signal of Trp. Under the optimal experimental conditions, a linear relationship in the range of 0.01–20 μM and 20–80 μM for Trp was established with detection limit of 5.7 nM (S/N = 3). Finally, the proposed sensor was practically applied by evaluation and determination of Trp from various sourcing samples including human serum and pharmaceutical samples.