Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Aryldiazonium Salts to Azo Dyes: Diazo Coupling01:11

Aryldiazonium Salts to Azo Dyes: Diazo Coupling

The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.
2° Amines to N-Nitrosamines: Reaction with NaNO201:20

2° Amines to N-Nitrosamines: Reaction with NaNO2

Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
Amines to Sulfonamides: The Hinsberg Test01:23

Amines to Sulfonamides: The Hinsberg Test

The Hinsberg test is a method to identify primary, secondary and tertiary amines, named after its pioneer, Oscar Hinsberg. Here, amines are treated with benzenesulfonyl chloride, also known as the Hinsberg reagent, in the presence of an excess of aqueous base, followed by acidification. Based on the nature of the amines, different changes are observed.
Generally, a primary amine reacts with the Hinsberg reagent to produce an N-substituted benzenesulfonamide. The electron-withdrawing sulfonyl...
Automated Microbial Diagnostics01:24

Automated Microbial Diagnostics

Automated diagnostic analyzers have transformed clinical microbiology by providing rapid and reliable methods for pathogen identification and antibiotic susceptibility testing. Among these systems, the Vitek 2 is widely used because it automates the traditionally labor-intensive processes of microbial identification (ID) and antibiotic susceptibility testing (AST), delivering standardized and timely results that are essential for effective patient care.Microbial Identification with ID CardsThe...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism01:37

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism

Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Performance of TB Antigen-Based Skin Tests Amongst Healthcare Workers-Sevagram, India, 2023-2024.

Open forum infectious diseases·2026
Same author

Safety and immunogenicity of a pentavalent meningococcal conjugate vaccine versus a quadrivalent meningococcal conjugate vaccine in adults in India: an observer-blind, randomised, active-controlled, phase 2/3 study.

The Lancet. Infectious diseases·2024
Same author

Seropersistence of SII-ChAdOx1 nCoV-19 (COVID-19 vaccine): 6-month follow-up of a randomized, controlled, observer-blind, phase 2/3 immuno-bridging study in Indian adults.

Human vaccines & immunotherapeutics·2024
Same author

SCOPE: Surveillance of COVID-19 in pregnancy- results of a multicentric ambispective case-control study on clinical presentation and maternal outcomes in India between April to November 2020.

PloS one·2023
Same author

A phase 2/3, participant-blind, observer-blind, randomised, controlled study to assess the safety and immunogenicity of SII-ChAdOx1 nCoV-19 (COVID-19 vaccine) in adults in India.

EClinicalMedicine·2021
Same author

Nurturing Care Interventions for Realizing the Development Potential of Every Child: From Pilot to Scale Up in Maharashtra.

Indian pediatrics·2021
Same journal

Tailoring oxygen vacancy of WO<sub>3</sub> nanoparticles for high-performance gas sensing: room-temperature NO<sub>2</sub> and low-temperature triethylamine detection.

Talanta·2026
Same journal

Mixed potential acetone sensor based on LaBaCo<sub>2-x</sub>Fe<sub>x</sub>O<sub>5±δ</sub> (x=0, 0.05 and 0.2) sensing electrode and yttria-stabilized zirconia for non-invasive diagnosis of diabetes.

Talanta·2026
Same journal

A nanowire-based fluorescent sensor for detecting hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) dyshomeostasis in cell body and synapse of Alzheimer's disease (AD) cell model.

Talanta·2026
Same journal

Ultra-sensitive determination of cyclopiazonic acid in complex food samples via competitive time-resolved luminescence immunoassays coupled to green microextraction.

Talanta·2026
Same journal

Integrated analytical characterization and multiscale modeling of supramolecular interactions in lumefantrine-curcumin coamorphous systems with enhanced biopharmaceutical and anticancer performance.

Talanta·2026
Same journal

Pixel-wise assessment of industrial compost transformation by NIR hyperspectral imaging and chemometrics: an early-warning tool for process monitoring.

Talanta·2026
See all related articles

Related Experiment Video

Updated: Jun 28, 2026

Analytical Techniques for Assaying Nitric Oxide Bioactivity
11:28

Analytical Techniques for Assaying Nitric Oxide Bioactivity

Published on: June 18, 2012

Sensitive tests for nitrite through azo-dye formation.

B S Garg1, Y L Mehta, M Katyal

  • 1Department of Chemistry, University of Delhi, Delhi 110007, India.

Talanta
|January 1, 1976
PubMed
Summary
This summary is machine-generated.

This study introduces a sensitive and selective method for detecting nitrite using azo-dyes derived from sulphanilic acid and pyridinols. The developed colorimetric system offers enhanced sensitivity for nitrite determination in water samples.

More Related Videos

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
08:23

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds

Published on: February 16, 2022

Measuring Nitrite and Nitrate, Metabolites in the Nitric Oxide Pathway, in Biological Materials using the Chemiluminescence Method
08:25

Measuring Nitrite and Nitrate, Metabolites in the Nitric Oxide Pathway, in Biological Materials using the Chemiluminescence Method

Published on: December 25, 2016

Related Experiment Videos

Last Updated: Jun 28, 2026

Analytical Techniques for Assaying Nitric Oxide Bioactivity
11:28

Analytical Techniques for Assaying Nitric Oxide Bioactivity

Published on: June 18, 2012

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
08:23

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds

Published on: February 16, 2022

Measuring Nitrite and Nitrate, Metabolites in the Nitric Oxide Pathway, in Biological Materials using the Chemiluminescence Method
08:25

Measuring Nitrite and Nitrate, Metabolites in the Nitric Oxide Pathway, in Biological Materials using the Chemiluminescence Method

Published on: December 25, 2016

Area of Science:

  • Analytical Chemistry
  • Environmental Chemistry

Background:

  • Nitrite detection is crucial for water quality assessment.
  • Existing colorimetric methods for nitrite often lack sensitivity or selectivity.

Purpose of the Study:

  • To develop a highly sensitive and selective method for nitrite detection.
  • To apply the developed method for determining nitrite levels in water samples.

Main Methods:

  • Diazotization of sulphanilic acid with nitrite.
  • Coupling of the resulting diazonium cation with pyridinols to form red azo-dyes.
  • Spectrophotometric analysis of the azo-dyes for nitrite quantification.

Main Results:

  • The azo-dye formation provides a sensitive colorimetric response to nitrite.
  • The method demonstrates high selectivity, with minimal interference from other ions.
  • Accurate determination of nitrite in various water samples was achieved.

Conclusions:

  • The novel azo-dye system offers a superior alternative for sensitive and selective nitrite detection.
  • This method is suitable for routine monitoring of nitrite in environmental water samples.