A novel kinetic determination of nitrite based on the perphenazine-bromate redox reaction

Recent advances in electrochemical approaches for detection of nitrite in food samples

Nitrite is a common ingredient in the industry and agriculture; it is everywhere, like water, food, and surroundings. Recently, several approaches have been developed to measure the nitrite levels. So, this review was presented as a summary of many approaches utilized to detect the nitrite. Furthermore, the types of information that may be acquired using these methodologies, including optic and electrical signals, were discussed. In electrical signal methods, electrochemical sensors are usually developed using different materials, including carbon, polymers, oxides, and hydroxides. At the same time, optic signals receiving techniques involve utilizing fluorescence chromatography, absorption, and spectrometry instruments. Furthermore, these methodologies' benefits, drawbacks, and restrictions are examined. Lastly, due to the efficiency and fast means of electrochemical detectors, it was suggested that they can be used for detecting nitrite in food safety. Futuristic advancements in the techniques used for nitrite determination are subsequently outlined.

Current and emerging trends of inorganic, organic and eco-friendly corrosion inhibitors

Effective corrosion control strategies are highly desired to reduce the fate of corrosion. One widely adopted approach is the use of corrosion inhibitors, which can significantly mitigate the detrimental effects of corrosion. This systematic review provides a thorough analysis of corrosion inhibitors, including both inorganic and organic compounds. It explores the inhibition mechanisms, highlighting the remarkable inhibitive efficiency of organic compounds attributed to the presence of heteroatoms and conjugated π-electron systems. The review presents case studies and investigations of corrosion inhibitors, shedding light on their performance and application potential. Moreover, it compares the efficacy, compatibility, and sustainability of emerging environmentally friendly corrosion inhibitors, including biopolymers from natural resources as promising candidates. The review also highlights the potential of synergistic impacts between mixed corrosion inhibitors, particularly organic/organic systems, as a viable and advantageous choice for applications in challenging processing environments. The evaluation of inhibitors is discussed, encompassing weight loss (WL) analysis, electrochemical analysis, surface analysis, and quantum mechanical calculations. The review also discusses the thermodynamics and isotherms related to corrosion inhibition, further improving the understanding of inhibitor's behavior and mechanisms. This review serves as a valuable resource for researchers, engineers, and practitioners involved in corrosion control, offering insights and future directions for effective and environmentally friendly corrosion inhibition strategies.

Ultrahigh-Sensitivity Capillary Electrophoresis Analysis of Trace Amounts of Nitrate and Nitrite in Environmental Water Samples

The role of nitrite (NO2−) and nitrate (NO3−) is essential in the global nitrogen cycle. Monitoring their concentration in environmental and industrial aqueous samples, surface water, soil, food and agricultural products are of high importance. Especially, the effect of anthropogenic emission, i.e., intensified agriculture is essential due to the overuse of nitrogen, phosphorus and potassium fertilizers. The most widely utilized methods for nitrate and nitrite determination are colorimetry, potentiometry, UV absorption and liquid chromatography. Among them, UV spectroscopy is the most frequently used technique due to the fact of its versatility and simplicity. However, there are industrial and academic needs to develop new methods to overcome some drawbacks of the currently used techniques such as an inadequate limit of detection and potential interferences with organic compounds in the sample. In this paper, we report on the development of a new analytical method based on capillary electrophoresis separation with high-sensitivity UV detection, capable of measuring trace concentrations of nitrite and nitrate well below the current limits of UV spectroscopy methods. During the development process special attention was paid to practical aspects, i.e., the method was tested to quantify nitrate and nitrite in various surface water samples.

Phenosafranin-Based Colorimetric-Sensing Platform for Nitrite Detection Enabled by Griess Assay

A facile and effective colorimetric-sensing platform based on the diazotization of phenosafranin for the detection of NO 2 - under acidic conditions using the Griess assay is presented. Diazotization of commercial phenosafranin produces a color change from purplish to blue, which enables colorimetric quantitative detection of NO 2 - . Optimal detection conditions were obtained at a phenosafranin concentration of 0.25 mM, HCl concentration of 0.4 M, and reaction time of 20 min. Under the optimized detection conditions, an excellent linearity range from 0 to 20 μM was obtained with a detection limit of 0.22 μM. Favorable reproducibility and selectivity of the colorimetric sensing platform toward NO 2 - were also verified. In addition, testing spiked ham sausage, bacon, and sprouts samples demonstrated its excellent practicability. The presented colorimetric sensing platform is a promising candidate for the detection of NO 2 - in real applications.

A review on spectroscopic methods for determination of nitrite and nitrate in environmental samples

Nitrate is an important pollutant found in environmental samples. Nitrate and nitrite pose various environmental as well as health hazards. Different methods of determining nitrate in various environmental samples developed during previous years include spectrophotometric, chemiluminescence, electrochemical detection, chromatographic, capillary electrophoretic, spectrofluorimetric methods. Out of these, methods based on spectroscopic detection of nitrate have been discussed in this review article due to their easy availability, high sensitivity, low detection limit, economical and facile nature. Methods based on spectrophotometry, Raman Spectroscopy, IR and FTIR Spectroscopy, atomic absorption spectroscopy (AAS), fluorescence spectroscopy, chemiluminescence, mass spectroscopy, molecular emission cavity analysis (MECA), electron paramagnetic resonance spectrometry (EPR) and nuclear magnetic resonance spectroscopy (NMR) have been reviewed. The basic principle, detection limits, detection range, RSD%, sample throughput/h, advantages and disadvantages have been discussed.

Methods for the detection and determination of nitrite and nitrate: A review

Various techniques for the determination of nitrite and/or nitrate developed during the past 15 years were reviewed in this article. 169 references were covered. The detection principles and analytical parameters such as matrix, detection limits and detection range of each method were tabulated. The advantages and disadvantages of various methods were evaluated. In comparison to other methods, spectrofluorimetric methods have become more attractive due to its facility availability, high sensitivity and selectivity, low limits of detection and low-cost.

Spectrophotometric determination of nitrite in soil and water using cefixime and central composite design

The present paper seeks to develop a simple method for the spectrophotometric determination of nitrite in soil and water samples and also measure optimum reaction conditions along with other analytical parameters. The method is based on the diazotization-coupling reaction of nitrite with cefixime and 1-naphthylamine in an acidic solution (Griess reaction). The final product that is an azo dye has an orange color with maximum absorption at 360 nm which Beer's Law is obeyed over the concentration range 0.02-15.00 mg L(-1) of nitrite. Optimal conditions of the variables affecting the reaction were obtained by central composite design (CCD). A detection limit of 4.3×10(-3) mg L(-1) was obtained for determination of nitrite by the proposed method. The proposed method was successfully applied to determine nitrite in soil and water samples. The molar absorptivity of the product of the reaction and RSD in determination of nitrite in real samples are 4.1×10(3) (L mol(-1) cm(-1)) and lower than 10%, respectively.

Development of a selective and pH-independent method for the analysis of ultra trace amounts of nitrite in environmental water samples after dispersive magnetic solid phase extraction by spectrofluorimetry

This paper describes an innovative and rapidly dispersive magnetic solid phase extraction spectrofluorimetry (DMSPE-FL) method for the analysis of trace amounts of nitrite in some environmental water samples. The method includes derivatization of aqueous nitrite with 2, 3-diaminonaphthalene (DAN), analysis of highly fluorescent 2, 3-naphthotriazole (NAT) derivative using spectrofluorimetry after DSPME. The novelty of our method is based on forming NAT that was independent with the pH-responsive and was adsorbed on MMWCNT by hydrophobic attractions in both acidic and basic media. The extraction efficiency of the sorbent was investigated by extraction of nitrite. The optimum extraction conditions for NO2(-) were obtained as of extraction time, 1.5 min; 10mg sorbent from 160 mL of the sample solution, and elution with 1 mL of acetone/KOH. Under the optimal conditions, the calibration curves were obtained in the range of 0.1-80 µg L(-1) (R(2)=0.999) and LOD (S/N=3) was obtained in 34 ng L(-1). Relative standard deviations (RSD) were 0.6 % (five replicates at 5 μg L(-1)). In addition, the feasibility of the method was demonstrated with extraction and determination of nitrite from some real samples containing tap, mineral, sea, rain, snow and ground waters, with the recovery in standard addition to real matrix of 94-102 % and RSDs of 1.8-10.6%.

Catalytic solid substrate-room temperature phosphorimetry for the determination of residual perphenazine based on the electronic effect of rhodamine 6G

The rhodamine 6G(+) -perphenazine (Rhod 6G(+) -PPH) compound is formed in the ester-exchange reaction between -OH of PPH and -COOC2 H5 of Rhod 6G(+) . PPH was oxidized to a red compound (PPH') in the presence of K2 S2 O8 . Interestingly, the room temperature phosphorescence (RTP) of Rhod 6G(+) was quenched because the -OH of PPH' reacted with -COOC2 H5 of Rhod 6G(+) -PPH to form Rhod 6G(+) -PPH' and PPH, which decreased the π-electron density (δ) of the carbon atom in the Rhod 6G(+) -PPH' conjugated system and enhanced the nonradiation energy loss of the excited Rhod 6G(+) of the triplet state. The PPH content was directly proportional to the ΔIp of the system. Thus, a new catalytic solid-substrate room temperature phosphorimetry (SSRTP) method was established for the determination of PPH. The method had high sensitivity (the limit of detection was 0.019 fg/spot, corresponding to a concentration of 4.8 × 10(-14)  g/mL; the sampling quantity was 0.40 μL/spot), good selectivity, convenience and speed. The analytical results were in accordance with those of high-performance liquid chromatography (HPLC). The structures of Rhod 6G(+) , PPH and Rhod 6G(+) -PPH were characterized by infrared spectra. The reaction mechanism by which PPH was determined is discussed.

Small-volume fiber-optic evanescent-wave absorption sensor for nitrite determination

A novel small-volume fiber-optic evanescent-wave absorption sensor based on the Griess-Ilosvay reaction has been developed and evaluated for nitrite determination. The sensor was constructed by inserting a decladded optical fiber into a transparent capillary to form an annular column microchannel. The Evanescent wave (EW) field produced on the optical fiber core surface penetrated into the surrounding medium and interacted with the azo dye, which was generated by the reaction of nitrite and nitrite-sensitive reagents. The detector was designed to be parallel to the axis of the optical fiber. The defined absorbance was linear with the concentration of nitrite in the range from 0.05 to 10 mg L(-1), and the detection limit was 0.02 mg L(-1) (3sigma) with the relative standard deviation (RSD) of 2.6% (n = 8). The present sensor was successfully used to determine nitrite in real samples of mineral water, tap water, rain water, and seawater. The results were consistent with the data obtained by standard spectrophotometric method, showing potential of the proposed sensor for practical application.