Related Experiment Video
Updated: Jul 16, 2026
08:07
Spectrophotometric Determination of Phycobiliprotein Content in Cyanobacterium Synechocystis
Published on: September 11, 2018
Spectrophotometric determination of aqueous cyanide using a revised phenolphthalin method
David Cacace1, Heidi Ashbaugh, Naomi Kouri
1Department of Chemistry and Physics, University of North Florida, Jacksonville, FL 32224, USA.
Analytica Chimica Acta
|April 3, 2007
Summary
This study enhances the phenolphthalin method for cyanide analysis, creating a sensitive spectrophotometric technique. The revised method offers fast kinetics and a low detection limit for environmental water samples.
Area of Science:
- Analytical Chemistry
- Environmental Chemistry
Background:
- Cyanide analysis is crucial for environmental monitoring.
- Existing phenolphthalin methods have limitations in sensitivity and robustness.
Purpose of the Study:
- To revise the phenolphthalin method for cyanide analysis.
- To develop a robust and sensitive spectrophotometric method for cyanide detection.
Main Methods:
- Modification of the phenolphthalin reagent by adding EDTA.
- Spectrophotometric analysis for cyanide determination.
Main Results:
- The revised method exhibits fast kinetics.
- A linear dynamic range of 0.01-3.0 ppm cyanide was achieved.
- A detection limit of 5 ppb for cyanide was established.
Conclusions:
- The EDTA-modified phenolphthalin method is a sensitive and robust approach for cyanide analysis.
- The method is suitable for determining cyanide in environmental waters with minimal interferences.
More Related Videos
Related Concept Videos
01:19Precipitation Titration: Endpoint Detection Methods
In argentometric precipitation titrations, endpoints can be detected visually by the Mohr, Volhard, and Fajans methods. In the Mohr method, adding a soluble chromate indicator gives an initial yellow color to the analyte solution. As the titrant is added, the first excess of silver ions forms a red silver chromate precipitate, marking the endpoint. The solution pH should be maintained at about 8 by adding solid CaCO3.
In the Volhard method, a standard excess of AgNO3 is first added to the...
In the Volhard method, a standard excess of AgNO3 is first added to the...
04:08Determining the pH of Salt Solutions
The pH of a salt solution is determined by its component anions and cations. Salts that contain pH-neutral anions and the hydronium ion-producing cations form a solution with a pH less than 7. For example, in ammonium nitrate (NH4NO3) solution, NO3− ions do not react with water whereas NH4+ ions produce the hydronium ions resulting in the acidic solution. In contrast, salts that contain pH-neutral cations and the hydroxide ion-producing anions form a solution with a pH greater than 7. For...
01:23Redox Titration: Iodimetry and Iodometry
Iodometry and iodimetry are analytical methods used to determine the concentration of oxidizing or reducing agents using iodine. In iodometric titrations, the oxidizing analyte solution is usually acidified and treated with an excess of iodide ions, which generates an equivalent amount of iodine in equilibrium with triiodide. The released iodine is subsequently titrated directly against a standardized reducing agent. As the dilute iodine color becomes pale yellow, a few drops of freshly...
01:21Redox Titration: Overview
Redox titration is a chemical analysis technique used to determine the concentration of an unknown substance by measuring the electron transfer in a redox (reduction-oxidation) reaction. The process involves gradually adding a titrant with a known concentration of an oxidizing or reducing agent, to the analyte, the solution with an unknown concentration, until reaching the endpoint, which indicates the completion of the reaction between the two substances. Ensuring the analyte is in a single...
02:39Indicators
Certain organic substances change color in dilute solution when the hydronium ion concentration reaches a particular value. For example, phenolphthalein is a colorless substance in any aqueous solution with a hydronium ion concentration greater than 5.0 × 10−9 M (pH < 8.3). In more basic solutions where the hydronium ion concentration is less than 5.0 × 10−9 M (pH > 8.3), it is red or pink. Substances such as phenolphthalein, which can be used to determine the pH of a solution, are called...
01:26Precipitation Titration: Overview
Precipitation titration involves the reaction of a titrant and an analyte to generate an insoluble precipitate. While precipitation titration uses various precipitating agents, silver nitrate is the most common precipitating reagent; titrations involving Ag+ are called argentometric titrations. Usually, the endpoint in a precipitation titration can be detected by visual indicators.
A precipitation titration curve demonstrates the change in concentration of the titrant or analyte upon adding the...
A precipitation titration curve demonstrates the change in concentration of the titrant or analyte upon adding the...