Alternative mass reference standards for direct analysis in real time mass spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry

Background:

• Mass spectrometry requires reliable calibration standards for accurate mass measurements.
• Direct Analysis in Real Time (DART) is a versatile ionization technique.
• Existing standards may have limitations in specific mass ranges or ionization modes.

Purpose of the Study:

• To evaluate amine-terminated polyether and fluorinated materials as mass calibration standards for DART mass spectrometry.
• To identify effective positive-ion and negative-ion reference standards for DART analysis.

Main Methods:

• Mass spectra were acquired using a time-of-flight mass spectrometer with a DART ion source.
• Reference standards were analyzed by direct insertion into the DART gas stream.
• Commercial materials including Jeffamine® M-600, PFTBA, Ultramark 1621®, and Fomblin® Y were tested.

Main Results:

• Jeffamine® M-600 produced intense peaks for protonated molecules, suitable for positive-ion calibration.
• Fomblin® Y provided useful negative-ion reference spectra from m/z 85 to >3000.
• DART mass spectra of Ultramark 1621® were consistent with previous FAB and ESI results.

Conclusions:

• Jeffamine-M600 is a convenient alternative to polyethylene glycol (PEG) for DART positive-ion mass calibration.
• Fomblin Y is a suitable and cost-effective negative-ion reference standard for DART mass spectrometry.
• These identified standards enhance the reliability and scope of DART mass calibration.