Flow-through solid-phase energy transfer-room temperature phosphorescence for orthophosphate determinations at trace...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Spectroscopy

Background:

• Orthophosphate is a key nutrient in aquatic ecosystems, and its accurate quantification is crucial for environmental monitoring.
• Existing methods for orthophosphate determination may lack sensitivity or require complex sample preparation.
• Room temperature phosphorescence (RTP) offers a sensitive detection technique with potential for miniaturization and field applications.

Purpose of the Study:

• To develop and validate a novel flow-through solid-phase RTP optosensor for the sensitive determination of orthophosphate in aqueous samples.
• To investigate the mechanism of energy transfer between a phosphor donor and an orthophosphate-specific dye acceptor.
• To assess the analytical performance and potential interferences of the developed RTP method for real-world water sample analysis.

Main Methods:

• Development of a flow-through system incorporating a polymeric resin with immobilized erythrosine B as the RTP donor.
• On-line co-immobilization of phosphomolybdenum blue, formed from orthophosphate in the sample, onto the resin.
• Utilizing non-radiative energy transfer from erythrosine B to phosphomolybdenum blue, where energy transfer efficiency is modulated by orthophosphate concentration.
• Regeneration of the sensing phase using sodium hydroxide and methanol for continuous analysis.

Main Results:

• The method achieved a low detection limit of 0.5 ng/mL for orthophosphate with a 1 mL sample injection volume.
• Demonstrated successful application in determining orthophosphate in various natural water samples at trace levels (ng/mL).
• Established a clear inverse relationship between RTP emission intensity and orthophosphate concentration due to efficient energy transfer.

Conclusions:

• The developed flow-through solid-phase RTP optosensor represents a novel and highly sensitive method for orthophosphate analysis.
• The system offers advantages in terms of sensitivity, potential for automation, and applicability to environmental water monitoring.
• This RTP-based approach provides a promising alternative for the accurate and efficient determination of orthophosphate in aquatic environments.