An improved procedure for flow-based turbidimetric sulphate determination based on a liquid core waveguide and pulsed...

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Accurate sulphate determination is crucial for water quality assessment.
• Traditional turbidimetric methods can be time-consuming and generate significant waste.

Purpose of the Study:

• To develop an improved, efficient flow-based procedure for turbidimetric sulphate determination.
• To minimize reagent consumption and waste generation in sulphate analysis.
• To enhance sensitivity and accuracy for sulphate detection in various water samples.

Main Methods:

• A flow system utilizing solenoid micro-pumps for improved mixing and reduced reagent use.
• Two configurations were tested: a 1-cm optical path flow cell and a 100-cm liquid core waveguide flow cell.
• Nucleation process optimization by stopping flow prior to measurement.
• Periodic washing with EDTA in alkaline medium to prevent baseline drift in the long pathlength cell.

Main Results:

• The 1-cm cell achieved a linear response from 20-200 mg/L with a detection limit of 3 mg/L and a sampling rate of 33/hour.
• The 100-cm cell provided enhanced sensitivity, with a linear response from 7-16 mg/L and a detection limit of 150 µg/L at a sampling rate of 25/hour.
• Results for freshwater and rain water samples showed agreement with batch turbidimetry methods.

Conclusions:

• The developed flow-based procedures offer efficient and sensitive methods for turbidimetric sulphate determination.
• The system minimizes reagent consumption and waste, making it environmentally friendly.
• The method is suitable for analyzing sulphate levels in various water matrices, including freshwater and rainwater.