Simple and specific method for flow injection analysis determination of cationic surfactants in environmental and...

Area of Science:

• Analytical Chemistry
• Environmental Chemistry

Background:

• Cationic surfactants (CS) are widely used in consumer products and industries.
• Accurate determination of CS in environmental and commodity samples is crucial for quality control and environmental monitoring.

Purpose of the Study:

• To develop a simple, rapid, and specific flow injection analysis (FIA) method for determining various cationic surfactants.
• To establish the method's applicability for analyzing CS in diverse environmental and commodity samples.

Main Methods:

• A flow injection analysis (FIA) procedure was developed based on the enhancement of the Fe(III)-SCN(-) complex's color intensity by cationic surfactants.
• The method was optimized and validated using cetylpyridinium chloride (CPC) as a model surfactant, with measurements at 475 nm.

Main Results:

• The method demonstrated high sensitivity with a detection limit of 250 ppb for CPC and linearity over the 0.5-30.0 ppm range.
• The FIA method achieved a sample throughput of 100 samples per hour and showed minimal interference from common environmental ions.
• Apparent molar absorptivities for Fe(III)-SCN(-)-CS(+) complexes ranged from (2.10-4.30)x10(3) L mol(-1) cm(-1).

Conclusions:

• The proposed FIA method is a sensitive, rapid, and reproducible technique for determining cationic surfactants in environmental (wastewater) and commodity (detergents, soaps) samples.
• The FIA method offers advantages in terms of sensitivity, linearity, precision, and analytical conditions compared to manual methods.
• The developed procedure is robust and suitable for routine analysis of cationic surfactants in complex matrices.