In this work, norepinephrine (NE) was determined by an electrochemical sensor represented by a carbon paste electrode boosted using nitrogen-doped porous carbon (NDPC) derived from Spirulina Platensis microalga anchored CoFe2O4@ NiO and 1-Ethyl-3-methylimidazolium acetate (EMIM Ac) ionic liquid. The morphological characteristics of the catalyst were recorded by field emission scanning electron microscope (FE-SEM) images. Moreover, the electrochemical behavior of norepinephrine on the fabricated electrode was checked using various voltammetric methods. All tests were done at pH 7.0 as the optimized condition in phosphate buffer solution. The results from linear sweep voltammetry revealed that the electro-oxidation of norepinephrine was diffusion, and the diffusion coefficient value was obtained by chronoamperometry (D⁓6.195 × 10– 4). The linear concentration of the modified electrode was obtained from 10 to 500 μM with a limit of detection of 2.26 μM using the square wave voltammetry (SWV) method. The sensor selectivity was investigated using various species, and the results from stability and reproducibility tests showed acceptable values. The sensor's efficiency was tested in urine and pharmaceutical as real samples with recovery percentages between 97.1% and 102.82%.

A novel and reusable sensing platform for electrochemical detection of norepinephrine based on nitrogen-doped porous carbon anchored CoFe2O4@NiO nanocomposite
    Abstract
    1 Introduction
    2 Experimental
        2.1 Reagent and apparatus
        2.2 Nitrogen-doped porous carbon synthesis
        2.3 Nitrogen-doped porous carbon -CoFe2O4@NiO Nanocomposite procedure
        2.4 Electrode preparation
        2.5 Real sample preparation
    3 Results and discussion
        3.1 Characterization of nitrogen-doped porous carbon-CoFe2O4@NiO nanocomposite
        3.2 Sensor optimization
        3.3 Electrochemical studies
        3.4 Selectivity, stability and reproducibility
        3.5 Real sample evaluation
    4 Conclusions
    References

• Reza Mostafazadeh(Faculty of Pharmacy, Department of Analytical Chemistry, Ankara University, 06560 Ankara, Turkey)
• Yasamin Hamidian(Faculty of Pharmacy, Department of Analytical Chemistry, Ankara University, 06560 Ankara, Turkey)
• Nevin Erk(Faculty of Pharmacy, Department of Analytical Chemistry, Ankara University, 06560 Ankara, Turkey)
• Elena Niculina Dragoi(Cristofor Simionescu, Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, Bld. D. Mangeron, No 73, 700050 Iasi, Romania)