Characterization of polyphosphates by electrospray mass spectrometry

Area of Science:

• Analytical Chemistry
• Environmental Science
• Spectroscopy

Background:

• Conventional methods for polyphosphate analysis often require preseparation techniques like ion chromatography or capillary electrophoresis.
• These methods also necessitate UV-absorbing chromophores for detection, adding complexity to the analytical process.

Purpose of the Study:

• To characterize inorganic polyphosphates including orthophosphate, pyrophosphate, tripolyphosphate, trimetaphosphate, and tetrapolyphosphate using ESI-MS.
• To evaluate the selectivity, detection limits, and quantification capabilities of ESI-MS for polyphosphates in various matrices, including streamwater.

Main Methods:

• Electrospray ionization mass spectrometry (ESI-MS) was employed for the direct characterization of inorganic polyphosphates.
• The standard addition method was utilized for quantifying polyphosphates in streamwater samples.
• The influence of multi-polyphosphate components and salts on ESI-MS signal response was investigated.

Main Results:

• ESI-MS demonstrated high selectivity, enabling the detection of different polyphosphate species without preseparation.
• Detection limits for ESI-MS were found to be in the range of approximately 1 to 10 ng/mL.
• Linear signal response for single-component samples was observed from the limit of detection up to approximately 10 microg/mL, with quantification in streamwater successfully demonstrated.

Conclusions:

• ESI-MS is a powerful and selective tool for the characterization and quantification of inorganic polyphosphates, eliminating the need for UV-absorbing chromophores and preseparation methods.
• The study successfully quantified polyphosphates in streamwater, highlighting the method's applicability in environmental analysis.
• Interference from co-existing polyphosphates and salts can affect signal response at higher concentrations, necessitating careful method development for complex mixtures.