A novel in situ method for linear alkylbenzene sulfonate quantification in environmental samples using a digital...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Water Quality Monitoring

Background:

• Detergent surfactants, like linear alkylbenzene sulfonate (LAS), contaminate aquatic environments due to inadequate sewage treatment.
• Effective and rapid monitoring techniques are crucial for assessing and managing surfactant pollution in water bodies.
• Existing spectrophotometric methods can be time-consuming and generate significant waste.

Purpose of the Study:

• To develop and validate a novel digital image-based (DIB) method for the in situ quantification of LAS in water.
• To establish a smartphone-based analytical technique as a rapid, economical, and environmentally friendly alternative for water quality assessment.
• To enable real-time monitoring of LAS contamination in various aquatic ecosystems.

Main Methods:

• Development of a DIB method utilizing methylene blue for LAS detection.
• Image acquisition using a smartphone camera and analysis with free Color grab software.
• Validation against spectrophotometry using environmental samples from the Capibaribe River Estuary.

Main Results:

• The DIB method demonstrated high precision and accuracy, with a linear calibration curve (0.15–4.5 mg L⁻¹, R² = 0.993).
• Achieved a low limit of detection (6.0 μg L⁻¹) and recovery rates between 82.7% and 114%.
• No statistically significant difference was found between DIB method results and the reference spectrophotometric method.

Conclusions:

• The smartphone-based DIB method is a viable, innovative tool for in situ quantification of LAS in aquatic environments.
• The method offers advantages of speed, cost-effectiveness, minimal waste generation, and ease of use compared to traditional techniques.
• This approach facilitates real-time water quality monitoring, crucial for environmental protection and pollution management.