Determination of orthophosphates using a macro segmented flow analyzer (MSFA) based on colorimetric detection

Area of Science:

• Analytical Chemistry
• Environmental Chemistry
• Water Quality Analysis

Background:

• Orthophosphate analysis is crucial for assessing water and wastewater quality.
• Existing methods for orthophosphate detection often face limitations in sensitivity, range, or throughput.
• Macro segmented flow analysis (MSFA) offers a flexible platform for developing new analytical methods.

Purpose of the Study:

• To develop and optimize a sensitive macro segmented flow analysis (MSFA) method for orthophosphate determination.
• To enhance analytical performance, including sensitivity, working range, and sample throughput.
• To validate the developed MSFA method for the analysis of real-world water and wastewater samples.

Main Methods:

• Fabrication of an MSFA system with a reconfigurable manifold for adjustable sample/reagent ratios.
• Colorimetric detection at 880nm for orthophosphate quantification.
• Optimization of key parameters: sample tube length (1.6mm i.d., 50.0cm), reaction temperature (37.0°C), and molybdate concentration (0.0113M).

Main Results:

• The optimized MSFA method demonstrated a linear calibration model (r²=0.9970) over a working range of 0.01-2.00 mg/L orthophosphate.
• Achieved a high sample throughput of 40 samples per hour with a detection limit of 4.0 µg/L.
• Exhibited %R.S.D. values below 5%, indicating good precision.

Conclusions:

• The developed MSFA system provides a sensitive, efficient, and robust method for orthophosphate analysis.
• The larger internal diameter sample tube contributed to improved sensitivity, wider working range, and higher sample throughput.
• The MSFA method was successfully applied to the analysis of both water and wastewater samples, demonstrating its practical utility.