Simultaneous stopped-flow determination of 1- and 2-naphthol

Area of Science:

• Analytical Chemistry
• Spectrophotometry
• Chemical Kinetics

Background:

• Accurate quantification of naphthol isomers is crucial in environmental and industrial analysis.
• Existing methods may lack the sensitivity or specificity for simultaneous determination of 1- and 2-naphthol.

Purpose of the Study:

• To develop and validate a rapid kinetic method for the simultaneous determination of 1-naphthol and 2-naphthol.
• To enable the analysis of naphthol mixtures at low concentrations.

Main Methods:

• A stopped-flow technique coupled with spectrophotometry at 475 nm was employed.
• The method relies on the differential reaction rates of 1- and 2-naphthol with diazotized sulphanilic acid.
• Kinetic data at two specific time points were used for quantification.

Main Results:

• The method accurately determined mixtures of 1- and 2-naphthol at the mug/ml level.
• Successful analysis was achieved across a wide range of isomer ratios (20:1 to 1:5).
• A relative standard deviation of 1.5% was achieved.
• Ternary mixtures including carbaryl were also resolved.

Conclusions:

• The proposed kinetic method offers a sensitive and selective approach for simultaneous 1- and 2-naphthol determination.
• This technique is suitable for analyzing complex mixtures, including those containing pesticides like carbaryl.
• The stopped-flow spectrophotometric method provides a robust analytical solution.