Reduced matrix effects for anionic compounds with paired ion electrospray ionization mass spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry

Background:

• Matrix effects in HPLC-ESI-MS compromise quantitative analysis and reproducibility.
• Paired ion electrospray ionization (PIESI) mass spectrometry analyzes anions in positive ion mode by forming charged complexes.

Purpose of the Study:

• To investigate if PIESI-MS mitigates matrix effects compared to traditional methods.
• To evaluate PIESI-MS performance on different mass spectrometry platforms.

Main Methods:

• A controlled study using five analytes in synthetic groundwater and urine matrices.
• Analysis performed using two mass spectrometers: linear ion trap and triple quadrupole.
• Comparison of PIESI-MS in positive ion mode versus negative ion mode.

Main Results:

• PIESI-MS demonstrated reduced susceptibility to matrix effects compared to the negative ion mode.
• The PIESI-MS approach was effective on both tested mass spectrometry platforms.
• Less sample dilution was required with PIESI-MS to overcome ionization suppression.

Conclusions:

• PIESI-MS is a viable technique for mitigating matrix effects in quantitative analysis.
• The method allows for lower limits of detection and quantitation due to reduced ionization suppression.
• PIESI-MS offers improved analytical performance for ultra-low level anion detection.