determination of 2,4-dinitrophenylhydrazine using carbon paste modified with nanoparticles by cyclic voltammetry, high-performance liquid chromatography and spectrophotometry methods

The research deals with the manufacture of an electrode using modified carbon paste to determine 2,4-dinitrophenylhydrazine (2,4-dnphz), the modified carbon paste electrode (nio-ncqd/g-c3n4/mcpe). the results show the presence of oxidation and reduction peaks, and it is subject to a quasi-reversible system; the best value ​​of ph is (1) using sulfuric acid with a concentration of (0.1m), and scan rate is 100 mv sec-1, it was linearity range of (1-1000) µm for oxidation, and (100-1000) µm for reduction, with correlation coefficient (r2=0.9717) and (r2=0.9914) for each of them, respectively. the proposed electrochemical method was compared with two methods they are spectrophotometry at a wavelength 360)  nm( and high-performance liquid chromatography (hplc) at wavelengths (340 and 250) nm. it turned out that the electrochemical method (nio-ncqd/g-c3n4/mcpe) was superior to the spectrophotometry method in terms of the detection limit. it turns out that there is no significant difference between (hplc) and (nio-ncqd/g-c3n4/mcpe) in terms of accuracy.  the proposed electrochemical method is a new analytical method characterized by accuracy, repeatability, and reliability.