Electrochemical Detection of Hydrazine by Carbon Paste Electrode Modified with Ferrocene Derivatives, Ionic Liquid, and CoS2-Carbon Nanotube Nanocomposite.

The electrocatalytic performance of carbon paste electrode (CPE) modified with ferrocene-derivative (ethyl2-(4-ferrocenyl[1,2,3]triazol-1-yl)acetate), ionic liquid (n-hexyl-3-methylimidazolium hexafluorophosphate), and CoS2-carbon nanotube nanocomposite (EFTA/IL/CoS2-CNT/CPE) was investigated for the electrocatalytic detection of hydrazine. CoS2-CNT nanocomposite was characterized by field emission scanning electron microscopy, X-ray powder diffraction, and transmission electron microscopy. According to the results of cyclic voltammetry, the EFTA/IL/CoS2-CNT-integrated CPE has been accompanied by greater catalytic activities for hydrazine oxidation compared to the other electrodes in phosphate buffer solution at a pH 7.0 as a result of the synergistic impact of fused ferrocene-derivative, IL, and nanocomposite. The sensor responded linearly with increasing concentration of hydrazine from 0.03 to 500.0 μM with a higher sensitivity (0.073 μA μM-1) and lower limit of detection (LOD, 0.015 μM). Furthermore, reasonable reproducibility, lengthy stability, and excellent selectivity were also attained for the proposed sensor. Finally, EFTA/IL/CoS2-CNT/CPE was applied for the detection of hydrazine in water samples, and good recoveries varied from 96.7 to 103.0%.

Introduction

Hydrazine enjoys a multitude of industrial deployments today, although in the 1960s, it found predominant application as one of the propellants for spacecrafts and rockets.[1] However, it presently contributes significantly to industries and is utilized as corrosion inhibitor, catalyst, reducing agent, blowing agents, and so forth. Moreover, its derivatives find widespread usage in the agriculture sector as one of the insecticides. In addition, numerous hydrazine-based drugs exist in the pharmaceutical sector. Nonetheless, it suffers from detrimental impacts on the terrestrial as well as aquatic organisms so that the prolonged exposures to it at lower concentration can seriously hurt the respiratory system, livers, skin, kidneys, central nervous system (CNS), cardiovascular system, and the human DNA.[2] In addition, hydrazine has been listed as a carcinogen by the US Environmental Protection Agency,[3] thus making its accurate determination imperative.

Some analytical techniques have been applied to detect hydrazine, including luminescence,[4] spectrophotometry,[5] capillary electrophoresis,[6] spectrofluorimetry,[7] high-performance liquid chromatography (HPLC),[8] flow-injection analysis,[9] and gas chromatography-mass spectrometry.[10] These methods have proven to be sensitive and accurate, but their higher costs, usage of larger amounts of the environmentally unfriendly solvents, longer working time, the necessity of laborious pretreatment, etc. limit their application.[11] In addition, electrochemical techniques have a widespread utilization in analytical chemistry due to the simplified preparation process, faster responses, affordability, higher sensitivity and selectivity, and feasible miniaturization.[12−16] Consequently, they have been extensively utilized for the determination of hydrazine.[17−24]

Nevertheless, larger oxidation overpotential as well as poorer voltammetric response over the conventional bare electrode (unmodified electrode) surface has been considered as one of the prime challenges for detecting analytes directly and sensitively. The other problem pertaining to the analyte direct oxidation at bare electrode has been proposed; electrode surface passivation through an oxide film is created at the high anodic potential. Hence, in the electrochemistry field, modifying the electrodes has been considered as the special and prime phase that allows solving or diminishing the above problems.[25−31] Consequently, it is of high importance to choose substances to modify electrodes for fabricating an electrochemical sensor with enhanced performance and sensitivity.

Considering the accelerated advances in nanoscience, nanomaterials have garnered immense attention for creating newer electrochemical sensors due to their very good electrical conductivity, larger surface areas, and acceptable biocompatibility.[32−35] For example, transition-metal sulfides are proposed as one of the active nanomaterials due to their prominent features appropriate for uses in catalysis, energy, and so forth. Particularly, cobalt disulfide (CoS2) is one of the potent materials for electrode modification due to its higher catalytic abilities.[36,37] Furthermore, conductivity for sulfides is commonly greater than the corresponding oxides because of their abilities to facilitate the transfer of electrons;[38] additional advantages include higher active-edge position and larger specific surface area for CoS2.[39,40] To enhance the electronic conductivity and electrochemical performance of CoS2, the combination of CoS2 with carbon nanomaterials is a useful strategy;[41,42] CNTs are often deployed to fabricate the composite substances for the new electrode modifiers because of their excellent mechanical features, acceptable physical features, wider potential window, and increased catalytic activities.[43,44]

Ferrocene and the respective derivatives have been proposed as one of the classes of electron mediators with very good redox electroactivities and improved electron-rich sandwich-type structure because of their reversible redox behavior of ferrocene to ferrocene+.[45] Moreover, faster transfer of electron as well as two-state redox stability have been considered the other promising electrochemical feature displayed by Ferrocene and the similar compounds, making them very good mediators.[46,47]

Ionic liquids (ILs) are the stable salts comprising organic or inorganic anion and organic cation and can be maintained in a liquid state within a broad range of temperatures.[48] They possess very good chemicophysical features like acceptable solvating features, high chemical and thermal stabilities, nonflammability, very little vapor pressure, higher conductivity, and wider electrochemical windows.[49] As green solvents, ILs are attractive and effective pasting binders rather than nonconductive organic binders to procure the carbon composite electrodes.[50−52]

Thus, the strategy presented here is based on the combination of ferrocene-derivative, IL, and CoS2-CNT nanocomposite to design a new voltammetric sensor for the electrochemical determination of hydrazine. The electrochemical studies revealed that this new sensor has an excellent electrocatalytic activity to oxidize hydrazine with numerous benefits like operational simplicity, higher sensitivity, prolonged stability, good reproducibility, and remarkable selectivity. Furthermore, the introduced electrochemical sensor has been substantially utilized for the detection of hydrazine in various water specimens.

Experimental Section

Apparatus and Chemicals

An Autolab potentiostat/galvanostat (PGSTAT 302N, Eco-Chemie; the Netherlands) has been employed to make the electrochemical measurements. General Purpose Electrochemical System (GPES) software has been applied for controlling the testing condition. In addition, a conventional three-electrode cell has been utilized at 25 ± 1 °C, with a platinum wire, EFTA/IL/CoS2-CNT/CPE, and Ag/AgCl/KCl (3.0 M) electrodes the as auxiliary, working, and reference electrodes, respectively. Finally, a Metrohm 710 pH meter has been used to measure the pH.

Hydrazine and other used reagents were of analytical grade. Merck (Darmstadt, Germany) supplied these materials. Ethyl2-(4-ferrocenyl[1,2,3]triazol-1-yl)acetate was synthesized in our laboratory as reported previously.[53] In addition, ortho-phosphoric acid as well as the respective salts (KH2PO4, K2HPO4, and K3PO4) with a pH ranging between 2.0 and 9.0 has been utilized to procure buffer solution. The CoS2-CNTs nanocomposite was prepared according to the description outlined earlier.[54]

Preparation of CoS2-CNT and Electrode

Commercialized CNT (Sigma-Aldrich) and CoS2 (Sigma-Aldrich) were mixed in a weight ratio of 5:2 by ball-milling with zirconia balls for 14 h to produce CoS2-CNT. EFTA/IL/CoS2-CNT/CPE was prepared via dissolution of 0.01 g of ferrocene-derivative in 3 mL of diethyl ether and subsequently a pestle and mortar were used to grind into 0.94 g of graphite powder and 0.05 g of CoS2-CNT nanocomposite. In the next step, 0.6 mL of paraffin and 0.3 mL of IL were poured into the obtained mixture and blended for 15 min until a uniformly moist paste was obtained. Next, this paste was packed at the bottom of a glass tube (3.4 mm i.d. and 10 cm in length) and a copper wire was placed on the carbon paste, to establish the electrical contact. To compare our results, controls were prepared by similar protocols such as ferrocene-derivative modified CPE (EFTA/CPE) without CoS2-CNT and IL, CoS2-CNT-modified CPE (CoS2-CNT/CPE) without ferrocene-derivative and IL, and unmodified CPE in the absence of ferrocene-derivative, IL, and CoS2-CNT.

The surface areas of the EFTA/IL/CoS2-CNT/CPE and the bare CPE were obtained by cyclic voltammetry (CV) using 1 mM K3Fe(CN)6 at different scan rates. Using the Randles–Sevcik formula[55] for EFTA/IL/CoS2-CNT/CPE, the electrode surface was found to be 0.306 cm2, which was ∼3.4 times greater than bare CPE.

Preparation of the Real Samples

According to the research design, we utilized various samples of water, river water, drinking water, and tap water (from the laboratory) as the real samples. The water samples were filtered three times prior to the analysis and varying amounts of hydrazine was added into the water samples for subsequent standard analysis method.

Results and Discussion

Characterization of the CoS2-CNT Nanocomposite

The field emission scanning electron microscopy (FESEM) images of CoS2 and CNT are shown in Figure a–c; CNT had ∼5 nm diameter size and CoS2 nanoparticles (NPs) show ∼100 nm diameter size, which could be confirmed with transmission electron microscopy (TEM) studies. The X-ray powder diffraction (XRD) results confirmed a single phase for the CoS2-CNT nanocomposite (Figure ). After the ball-milling process for the mixed CoS2 and CNTs, CoS2 NPs were trapped in the CNTs cluster. This sponge-like structure was favorable for the easier diffusion of ionic liquid electrolyte in a cathode material, making CoS2 more accessible as active sites (Figure ). As demonstrated in Figure S1 of the Supporting Information, the Brunauer–Emmett–Teller surface area of the CoS2-CNT nanocomposite was measured to be 168 m2 g–1.

Figure 1

FESEM images of (a) CoS2 NPs. SEM images of (b) low and (c) magnified CoS2-CNT nanocomposite.

Figure 2

XRD pattern for the CoS2-CNT nanocomposite.

Figure 3

TEM images of the CoS2-CNT nanocomposite in different magnifications.

Electrochemical Behavior of Hydrazine on EFTA/IL/CoS2-CNT/CPE

The electrochemical behavior of hydrazine depends upon the pH value of the aqueous solution. On the one hand, optimizing the solution pH is crucial for obtaining hydrazine electrocatalytic oxidation. Hence, electrochemical behaviors of hydrazine were examined in 0.1 M phosphate buffer solution (PBS) at distinct pH values (2.0 < pH < 9.0) at the EFTA/IL/CoS2-CNT/CPE surface using the CV method. Analyses revealed higher favorability of hydrazine electrocatalytic oxidation at the EFTA/IL/CoS2-CNT/CPE surface at neutral conditions in comparison to the basic or acidic media (Figure ). Finally, we selected pH 7.0 as an optimal value to electrocatalyze hydrazine oxidation at the EFTA/IL/CoS2-CNT/CPE surface.

Figure 4

Plot of Ip vs pH obtained from DPVs of EFTA/IL/CoS2-CNT/CPE in a solution containing 200.0 μM of hydrazine in 0.1 PBS with different pHs (2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, and 9.0).

The CV responses for electrochemical oxidation of 200.0 μM hydrazine at the unmodified CPE (curve b), IL/CPE (d), CoS2-CNT/CPE (curve e), EFTA/CPE (curve f), EFTA/IL/CPE (curve g), and EFTA/IL/CoS2-CNT/CPE (curve h) are shown in Figure ; the potential of the anodic peak is ∼860 mV for hydrazine oxidation over the surface of bare CPE (curve b) and IL/CPE (d), and 330 mV over the EFTA/IL/CoS2-CNT/CPE surface (curve f). Considering the aforementioned curves, the potential peak observed for hydrazine oxidation over the surface of the modified electrode shifts is 530 mV to the negative values in comparison to the surface of the bare electrode. With regard to the hydrazine oxidation on the EFTA/CPE (curve f), EFTA/IL/CPE (curve g), and EFTA/IL/CoS2-CNT/CPE (curve h) surfaces, we observed an increase in the anodic peak current on the EFTA/IL/CoS2-CNT/CPE surface compared to that in EFTA/CPE and EFTA/IL/CPE, demonstrating an augmentation in the peak current through the introduction of both IL and CoS2-CNT nanocomposite in the modification of CPE. In addition, several advantages could be found for IL/CPE including faster electron transfer, appropriate antifouling features, high conductivity, and IL catalytic nature.

Figure 5

CVs of (a) bare CPE in 0.1 M PBS (pH 7.0); (b) as (a) in 200.0 μM hydrazine; (c) as (a) at the surface of EFTA/IL/CoS2-CNT/CPE; (d) as (b) at the surface of IL/CPE; (e) as (b) at the surface of CoS2-CNT/CPE; (f) as (b) at the surface of EFTA/CPE; (g) as (b) at the surface of EFTA/IL/CPE; and (h) as (b) at the surface of EFTA/IL/CoS2-CNT/CPE. In all cases, the scan rate was 10 mV s–1.

It is evident that even in the absence of hydrazine, a well-behaved redox reaction at EFTA/IL/CoS2-CNT/CPE in 0.1 M PBS (pH = 7.0) occurs (Figure curve c); however, in the presence of 200.0 μM hydrazine at EFTA/IL/CoS2-CNT/CPE (curve f), a noticeable increase in the anodic peak current is observed. According to these results, we suggest an EC′ catalytic mechanism[55] for the electrochemical oxidation of hydrazine at EFTA/IL/CoS2-CNT/CPE, as depicted in Scheme . It has been proposed that in a catalytic reaction, hydrazine is oxidized by the oxidized form of EFTA which is produced during an electrochemical reaction at the electrode surface.

Scheme 1

Electrocatalytic Oxidation of Hydrazine at EFTA/IL8-/CoS2-CNT/CPE

Effect of Scan Rate on the Results

LSV has been utilized to study the impacts of the scan rates on the electrocatalytic oxidation of hydrazine over the modified electrode surface. Figure shows that by enhancing the scan rate, the oxidation peak potential shifts to a more positive potential, which reflects the kinetic limitation of the electrochemical reaction. Additionally, the peak height (Ip) plot versus square of the scan rate root (ν1/2) displayed the linear range between 5 and 200 mV s–1, showing that at sufficient overpotential, the oxidation procedure was controlled by diffusion rather than the surface, as shown in Figure inset (A). Moreover, the plot of the scan rate-normalized current (Ip/ν1/2) vs the scan rate obviously showed a specific form of a typical electrocatalytic procedure as depicted in Figure inset (B).[55]

Figure 6

Linear sweep voltammograms (LSVs) of EFTA/IL/CoS2-CNT/CPE 0.1 M PBS (pH 7.0) containing 250.0 μM hydrazine at various scan rates of (a–h) 5, 10, 15, 30, 70, 100, 150, and 200 mV s–1, respectively. Insets: (A) variation of anodic peak current with the square root of scan rate and (B) variation of scan rate-normalized current (Ip/ν1/2) with scan rate.

In the next step, the Tafel plot that corresponded to the LSV curve with the increased sharpness at 5 mV s–1 scan rate is depicted in Figure . Moreover, the number of electrons involved in the rate-determining step may be approximated according to the Tafel slope under a rapid deprotonation step of hydrazine. This Tafel slope has been specified as 0.2166 V, revealing that the rate-determining step contains one electron in the electrode procedure, considering 0.72 for charge-transfer coefficient (α).

Figure 7

LSV (at 5 mV s–1) of the electrode in 0.1 M PBS (pH = 7.0) containing 250.0 μM hydrazine. The points are the data used in the Tafel plot (inset).

Chronoamperometric Analysis

According to the research design, chronoamperometric measurement of hydrazine has been accomplished using a modified electrode by setting the working electrode potential at 380 mV for diverse concentrations of hydrazine in the PBS at a pH 7.0, as shown in Figure . Moreover, the current seen for an electroactive moiety in the electrochemical reactions with the mass transport limitation can be described by the Cottrell equation.[55]here D and Cb are the diffusion coefficients (cm2 s–1) and the bulk concentration (mol cm–3), respectively.

Figure 8

Chronoamperograms obtained at EFTA/IL/CoS2-CNT/CPE in 0.1 M PBS (pH 7.0) for different concentrations of hydrazine: (a–f) 0, 0.1, 0.3, 0.6, 1.0, and 2.0 mM hydrazine. Insets: (A) Cottrell plot for the data from the chronoamperograms, (B) plot of the slope of the straight lines against hydrazine concentration and (C) dependence of IC/IL on t1/2 derived from the chronoamperogram data.

We drew experimental outputs of I vs t–1/2 with the most acceptable fits for diverse hydrazine concentrations, as shown in Figure , inset (A). In the next step, the slopes of the straight lines have been drawn on the opposite of hydrazine concentration (Figure , inset B). Considering the final slopes as well as the Cottrell equation, D mean value was found to be 2.1 × 10–6 cm2 s–1. Additionally, it is possible to evaluate the catalytic rate constant (k) with chronoamperometry for hydrazine reaction at EFTA/IL/CoS2-CNT/CPE regarding Galus’s equation.[56]where IC is the hydrazine catalytic current at EFTA/IL/CoS2-CNT/CPE, IL is the limiting current in the absence of hydrazine. γ = kCbt is the error function argument (Cb implies hydrazine bulk concentration). In case of a greater value of γ than 2, error function becomes 4. Hence, eq is shortened aswhere t is the time spent. According to eq , the slope of IC/IL versus t1/2 at a given concentration of hydrazine has been utilized for computing k for the catalytic process. Based on the final slopes shown in Figure , inset (C), k for hydrazine reaction at EFTA/IL/CoS2-CNT/CPE was obtained as 2.8 × 103 M–1 s–1.

Calibration Plot and Limit of Detection

In this step, differential pulse voltammetry (DPV) has been applied for determining the hydrazine content with different concentration gradients at a pH 7.0 (initial potential = 0.1 V, end potential = 0.53 V, step potential = 0.001 V, amplitude = 0.02 V). According to Figure , the association of the peak current of hydrazine with its concentrations is linear in the range 0.03–500.0 μM. The linear equation is as follows: y = 0.073x + 3.4261, the correlation coefficient is 0.9996.

Figure 9

DPVs of EFTA/IL/CoS2-CNT/CPE in 0.1 M PBS (pH 7.0) containing different concentrations of hydrazine: 0.03, 1.0, 5.0, 10.0, 30.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 350.0, 400.0, 450.0, and 500.0 μM of hydrazine, respectively. The inset: the peak current plot as the function of hydrazine concentrations in ranges from 0.03 to 500.0 μM.

In addition, the detection limit, Cm, of hydrazine was obtained using the following equationIn the above equation, m is the slope of the calibration plot (0.073 μA μM–1) and sb is the standard deviation of the blank response, which is obtained from 20 replicate measurements of the blank solution. The detection limit is 0.015 μM. The comparison of the results for the detection of hydrazine with different modified electrodes in the literature is listed in Table .

Table 1

Performance Comparison Study of the Purposed Electrochemical Sensor with Previously Published Articles for the Detection of Hydrazine

electrochemical sensor	method	linear range (μM)	limit of detection (μM)	sensitivity	ref
aβ-nickel hydroxide nanoplatelets/CPE	amperometry	1–1300	0.28	1.33 μA mM–1 cm–2	(1)
bPd/CNF-GCE	DPV	10–4000	2.9	8.69 ± 0.083 μA mM–1	(17)
cAu@Pt-NFs/GO/GCE	amperometry	0.8–429	0.43	1695.3 μA mM–1 cm–2	(18)
dPd NPs-EDAC/GCE	DPV	5–150	1.5	0.0218 μA μM–1	(19)
eGO/Chi/Pt/GCE	amperometry	20–10000	3.6	7.39 μA mM–1	(20)
fAg NPs/ZIF-67/CPE	amperometry	4–326 and 326–4700	1.45	327 and 147 μA mM–1 cm–2	(21)
gPt NPs/TiO2NSs/GCE	chronoamperometry	20–900	2	187.4 μA mM–1 cm–2	(22)
hCuO/CNT/SPE	chronoamperometry	5–50	5	70.72 μA μM–1 cm–2	(23)
iNG-PVP/AuNPs/SPCE	square wave voltammetry	2–300	0.07	1.370 μA μM–1 cm–2	(24)
EFTA/IL/CoS2-CNT/CPE	DPV	0.03–500.0	0.015	0.073 μA μM–1	This Work

β-Nickel hydroxide nanoplatelets modified carbon paste electrode.

Pd NPs/carbon nanofibers modified glassy carbon electrode.

Three-dimensional porous Au@Pt core–shell nanoflowers supported on graphene oxide modified glassy carbon electrode.

Pd NPs immobilized on ethylenediamine cellulose modified glassy carbon electrode.

Graphene oxide/chitosan/Pt NPs modified glassy carbon electrode.

Ag NPs on nano cobalt-based metal--organic framework (ZIF-67) modified carbon paste electrode.

Pt NPs/TiO2 nanosheets modified glassy carbon electrode.

Copper oxide NPs/carbon nanotube modified screen-printed electrode.

Nitrogen-doped graphene–poly(vinylpyrrolidone)/AuNPs modified screen-printed carbon electrode.

Interference Studies

It is well known that interference examinations have been conducted for understanding the effectiveness of the outputs to analyze hydrazine via the presence of diverse organic compounds and inorganic ions. Based on the common definition, the ratio of the interfering species concentration to the hydrazine refers to the tolerance limit, resulting in a relative error of <±5.0%. The possible interference has been examined by adding diverse ions and biological compounds such as Na+, Cl–, K+, NO3–, Ag+, Pb2+, glucose, sucrose, urea, and uric acid to PBS at a pH 7.0 in the presence of 50.0 μM hydrazine. It was found that the addition of these interfering species did not show any considerable impact on the hydrazine DPV signal. Hence, this modified electrode exhibited acceptable selectivity to detect hydrazine.

Reproducibility and Stability of EFTA/IL/CoS2-CNT/CPE

In this section, the reproducibility of the modified electrode was examined using five different sensors (EFTA/IL/CoS2-CNT/CPE) that were fabricated in the same condition containing 30.0 μM hydrazine by CV. The relative standard deviation (RSD) value for this compound was found to be 2.6%. This RSD value for the analysis of hydrazine reflects that the EFTA/IL/CoS2-CNT/CPE displayed good reproducibility property.

For checking our sensor stability, we kept the recommended sensor within the pH equal to 7.0 in the PBS for 2 weeks to test THE EFTA/IL/CoS2-CNT/CPE stability and, consequently, we recorded the CV of the solution consisting of 30.0 μM hydrazine to be compared to the CV observed prior to immersion. The oxidation peak of hydrazine did not change and in comparison to earlier responses to the current showed a less than 2.7% reduction in signal, reflecting acceptable stability of EFTA/IL/CoS2-CNT/CPE.

Real Sample Analysis

According to the research design, the as-proposed EFTA/IL/CoS2-CNT/CPE has been utilized to detect hydrazine in the water samples by the standard addition procedure. Moreover, Table reports the content as well as the recoveries of hydrazine. As shown in the table, recoveries were in the range from 96.7–103.0% with the relative standard deviation (RSD) of <3.6%. These results confirmed the ability of EFTA/IL/CoS2-CNT/CPE as a sensitive sensor for hydrazine analysis in the water specimens.

Table 2

Determination of Hydrazine in Water Samplesa

sample	spiked	found	recovery (%)	R.S.D. (%)
	0
	5.0	4.9	98.0	3.5
drinking water	7.5	7.6	101.3	2.1
	10.0	10.3	103.0	1.9
	12.5	12.3	98.4	2.8
	0
	5.0	5.1	102.0	2.6
tap water	6.0	5.9	98.3	3.0
	7.0	7.1	101.4	2.1
	8.0	7.8	97.5	1.9
	0
	4.0	4.1	102.5	1.7
River Water	6.0	5.8	96.7	3.6
	8.0	8.1	101.2	2.4
	10.0	9.9	99.0	2.5

All the concentrations are expressed in μM (n = 5).

Conclusions

The performance of a ferrocene-derivative compound as a mediator/IL/CoS2-CNT nanocomposite modified CPE was developed for the electrochemical sensing of oxidation of hydrazine. Ferrocene-derivative, IL, and CoS2-CNT nanocomposite as modifiers displayed stronger catalytic features. Hence, on the resultant EFTA/IL/CoS2-CNT/CPE, the anodic overpotential of hydrazine oxidation decreased; however, the oxidation peak current considerably improved. The fabricated sensing electrode displayed a linear range within 0.03–500.0 μM hydrazine having a detection limit of 0.015 μM and a sensitivity value of 0.073 μA μM–1. Moreover, the hydrazine sensor exhibited acceptable reproducibility, long-term stability, and excellent selectivity. EFTA/IL/CoS2-CNT/CPE has excellent accuracy in recovering hydrazine analysis in water samples. Therefore, the fabricated EFTA/IL/CoS2-CNT/CPE with prominent electrochemical features could be considered as one of a potent, reliable, and competitive candidates to detect diverse analytes.