Improvement of sensitivity in flow analysis by exploiting a multi-reversed software-assisted system

Area of Science:

• Analytical Chemistry
• Environmental Science
• Instrumentation Engineering

Background:

• Flow analysis techniques are crucial for chemical and environmental monitoring.
• Improving sensitivity and throughput in flow analysis remains a key challenge.
• Conventional methods may lack the precision and speed required for real-time analysis.

Purpose of the Study:

• To develop a software-assisted multi-reversed flow system for enhanced analytical sensitivity.
• To evaluate the system's performance using the Griess colorimetric reaction for nitrite determination in water.
• To compare the new system's sensitivity against continuous- and stopped-flow methods.

Main Methods:

• A flow system manifold was designed with solenoid valves, a peristaltic pump, and a photometric detector.
• Custom software was developed in Visual Basic 6.0 for system control and data acquisition.
• The Griess colorimetric reaction was employed to determine nitrite concentrations in water samples.

Main Results:

• Sensitivity, measured by calibration curve slope, improved 2.5-fold over continuous flow and 1.4-fold over stopped-flow.
• Achieved analytical throughput of 55 determinations per hour.
• Established a limit of detection of 5 µg/L, RSD < 2%, and a linear dynamic range up to 1800 µg/L.

Conclusions:

• The software-assisted multi-reversed flow system significantly improves sensitivity for nitrite determination.
• The system offers high analytical throughput and a low limit of detection, suitable for water quality monitoring.
• This approach represents a valuable advancement in flow analysis instrumentation.