Sensor For Determination Of Nitrite Research Articles

A Novel Zif-8@Zif-67/Au Core–Shell Metal Organic Framework Nanocomposite as a Highly Sensitive Electrochemical Sensor for Nitrite Determination

A Novel Zif-8@Zif-67/Au Core–Shell Metal Organic Framework Nanocomposite as a Highly Sensitive Electrochemical Sensor for Nitrite Determination

Construction of polythiophene-derivative films as a novel electrochemical sensor for highly sensitive detection of nitrite.

Herein, a novel, convenient, and highly selective electrochemical sensor for determination of nitrite based on a polythiophene-derivative film-modified glassy carbon electrode (GCE) was established. In this work, 2,5-di-thiophen-3-yl-thiazolo[5,4-d]thiazole (DTT), a novel thiophene derivative, was synthesized and used to form an original and excellent polymer film (PolyDTTF) on GCE through one-step electropolymerization for the first time. The modified electrodes were characterized by electron microscopy (SEM), Fourier transform infra-red spectroscopy (FT-IR), UV-visible spectra, Raman spectroscopy, and electrochemical technologies, in which the electrochemical sensor based on PolyDTTF was successfully constructed and demonstrated a significant electrocatalytic effect on nitrite. The influence of pH value, electrodeposition scanning times, scanning speed, and potential on the electrochemical behavior of nitrite were investigated in detail. Furthermore, the nitrite sensor exhibits excellent responses proportional to nitrite concentrations (R2 = 0.9972) over a concentration range of 5.5 × 10-9 ~ 3.5 × 10-5M with a detection limit (LOD) of 2nM, and has extremely good anti-interference ability for nitrite detection. This proposed sensor can be used to detect nitrite in actual samples, opening the possibility for applications in the food industry and environmental analysis.

SiO2/Al2O3/C grafted 3-n propylpyridinium silsesquioxane chloride-based non-enzymatic electrochemical sensor for determination of carcinogenic nitrite in food products

The excessive uptake of nitrite is perilous and detrimental for human health that prone to cancer disease. Herein, described the synthesis of SiO2/Al2O3/C material through the sol–gel procedure followed by grafting with 3-n propylpyridinium silsesquioxane chloride organic ligand for enhancing electrochemical activity. H-NMR, 13C NMR, and 29Si studies were performed for confirmation of surface functionalization through the grafting technique. The surface morphology was evaluated through SEM and TEM techniques. The material showed an irregular and flakes-like structure that exhibited more compactness and conglomerate structure with no segregation in phase was observed after grafting. The elemental composition was confirmed from EDX analysis. The electrochemical measurements were performed with cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and chronoamperometry. The prepared hybrid inorganic–organic composite Si/C/Al/SiPy+Cl- was applied for the modification of the glassy carbon (GC) electrode and assessed as a sensor for nitrite determination. The sensor showed the low limit of detection (0.01 μM), low limit of quantification (0.08 μM), wide linear response range (0.2–280 μM), and high sensitivity (410 μA·μM−1). It gave a quick response time of <1 s in the presence of 70 μM nitrite. The fabricated sensor showed high sensitivity, chemical stability, and insignificant interference from co-existing species present in sausage meat and food industry discharges. The repeatability of the sensor was evaluated as 2.5 % R.S.D.; for n = 10 at 50 μM nitrite.

Colorimetric microfluidic paper-based sensor for determination of nitrite in drinking water with enhanced color development

A low cost colorimetric microfluidic paper-based analytical device (µPAD) for the determination of nitrite in real samples with improved precision has been fabricated and its performance has been evaluated. The µPAD was fabricated by laser cutting and patterning on the paper and the nitrite concentration measurement is based on the modified Griess assay. In this assay, tartaric acid was used as an antioxidant reagent to increase Griess reagent stability. A novel geometrical design was used to achieve better color gradient over µPAD detection zone for improving the precision of the measurements. The results of measurement indicate that the fabricated device could successfully detect and quantify the nitrite concentration in real samples with the limit of detection of 15 μM. The results are in good accordance with the results of spectrophotometry. The fabricated sensor has the potential to be applied for monitoring of the trace level of nitrite in drinking water and environmental applications.

Coupling of digital image processing and three-way calibration to assist a paper-based sensor for determination of nitrite in food samples.

In this work, a novel and very interesting analytical methodology based on coupling of digital image processing and three-way calibration has been developed for determination of nitrite in food samples. Nitrite in contact with Griess reagent is able to produce a red-colored azo dye whose color intensity is correlated with nitrite concentration and here, a piece of Whatman filter paper impregnated with Griess reagent was used as the platform of the sensor and a SONY Xperia Z5 cell phone was used for image capturing from the sensor surface. To generate second-order data, the F-number of the camera's sensor was changed as an instrumental parameter. Two calibration models were constructed by unfolded partial least squares-residual bilinearization (U-PLS/RBL) and multiway-PLS/RBL (N-PLS/RBL) and then, their performance for prediction of nitrite concentration in test samples was evaluated and the results confirmed a good performance for U-PLS/RBL (REP = 3.25 ppm, RMSEP = 8.82 ppm, RMSEC = 4.62 ppm, Q2 = 0.99, γ−1 = 0.05 and LOD = 0.1 ppm) which was better than that for N-PLS/RBL (REP = 13.98 ppm, RMSEP = 37.86 ppm, RMSEC = 6.46 ppm, Q2 = 0.98, γ−1 = 0.07 and LOD = 0.15 ppm) in predicting concentration of nitrite in test samples which motivated us to choose it for the analysis of cabbage, carrot, lettuce, watermelon, onion, potato, kielbasa and sausage as real samples.

An electrochemical sensor for determination of nitrite based on Au nanoparticles decorated MoS2 nanosheets

An electrochemical sensor for the determination of nitrite was successfully fabricated via electro-depositing Au nanoparticles on a glassy carbon electrode (GCE) modified with MoS2 nanosheets. The morphology and composite of the resulted electrode were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The modified processes of the nanoAu-MoS2/GCE were monitored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The amperometric current–time (i–t) showed that the developed electrode had excellent response for sodium nitrite under the optimum conditions, and the oxidative current of sodium nitrite was proportionally correlated with its concentration (10–2100 μM) with a limit of detection (LOD) of 0.09 μM (S/N = 3), which can be employed in the determination of nitrite in river and drinking water with the advantages of good reproducibility, anti-interference, long-term stability and satisfactory recovery rate.

Ferromagnetic Iron Oxide Nanoparticles Modified Electrode as a Sensor for Determination of Nitrite

Ferromagnetic Iron Oxide Nanoparticles Modified Electrode as a Sensor for Determination of Nitrite

Cobalt Monoxide Nanoparticles Modified Glassy Carbon Electrodes as a Sensor for Determination of Nitrite

A new method for the determination of nitrite was established based on cobalt monoxide (CoO) nanoparticles modified glassy carbon electrode (CS-CoO/GCE). In 0.15mol/L pH 4.0 HAc-NaAc, the CS-CoO/GCE showed a remarkable catalytic and enhancement effect on oxidation of the nitrite. A linear dynamic range of 8.0×10-7 to 6.0×10-3 mol/L (R=0.997) with a detection limit of 1.0×10-7 mol/L was obtained. The electrochemical mechanism was been obtained. This method has been used to determine the content of nitrite in real samples.

Electrochemical sensor for sensitive determination of nitrite based on the PAMAM dendrimer-stabilized silver nanoparticles

Silver nanoparticles stabilized by PAMAM dendrimer were synthesized by a simple chemical reduction method. By this method, stable and well-distributed silver nanoparticles were formed due to the abundant terminated groups of PAMAM. Based on the Ag–PAMAM nanocomposite, a novel electrochemical sensor for the determination of nitrite was constructed. The Ag–PAMAM modified electrode exhibited excellent electrocatalytic performance for the oxidation of nitrite. The effects of pH and applied potential on the current response of Ag–PAMAM modified electrode toward nitrite were optimized to obtain the maximal sensitivity. In pH 6.0 phosphate buffer solution, the sensor displayed a wide linear range from 4.0μM to 1.44mM. Moreover, the sensor had the advantages of high sensitivity (265μAmM−1cm−2) and short response time (3s). The detection limit was estimated to be 0.4μM. Furthermore, the practicality of the proposed sensor for the determination of nitrite was achieved in tap water and milk sample.

Electropolymerization of Indole-3-acetic Acid on Glassy Carbon Electrode for Sensitive Detection of Nitrite

Highly uniform and adhesive films of poly(indole-3-acetic acid) (p-IAA) were fabricated on the glassy carbon electrode (GCE) by electropolymerization of indole-3-acetic acid (IAA). The p-IAA modified GCE (p-IAA/GCE) was constructed to develop a promising amperometric sensor for the sensitive determination of nitrite. Field emission scanning electron microscope (SEM) and electrochemical techniques were used for the surface characterization of the modified electrode. It was demonstrated that p-IAA modified GCE (p-IAA/GCE) exhibited remarkable electrocatalytic activity towards the oxidation of nitrite with obvious reduction of overpotential. Under the optimal conditions, the linear range for the detection of nitrite was 5.0×10-7 to 5.0×10-4 M with a high sensitivity of 0.105 AM-1, and a low detection limit of 1.0×10-7 M (S/N = 3). The influence of various anions and cations on the nitrite detection has been studied. The proposed method was successfully applied in the detection of nitrite in sausage samples, and the results were consistent with those obtained by UV-vis spectrophotometric methods.