An inductively coupled plasma-time-of-flight mass spectrometer for elemental analysis. Part III: Analytical...

Area of Science:

• Analytical Chemistry
• Spectroscopy

Background:

• Inductively coupled plasma mass spectrometry (ICP-MS) is a powerful analytical technique.
• Evaluating novel mass analyzers for ICP-MS is crucial for advancing elemental analysis.

Purpose of the Study:

• To assess the performance of a time-of-flight mass spectrometer (TOFMS) as a mass analyzer for ICP-MS.
• To investigate methods for improving precision and detection limits in TOFMS-ICP-MS.

Main Methods:

• Evaluation of TOFMS for ICP-MS signal stability and precision.
• Implementation of isotopic peak ratioing and internal standardization for precision enhancement.
• Assessment of two signal processing systems for detection limit determination.

Main Results:

• Long-term signal drift was 7-8% RSD; short-term precision ranged from 5-20%.
• Isotopic ratioing improved precision to ~0.5% for lead isotopes.
• Detection limits were 1-2 orders of magnitude poorer than commercial ICP-MS, but signal-to-noise improved 10-100x.
• Simultaneous multielement and multiisotope analysis achieved 0.4-2 ppb detection limits.

Conclusions:

• TOFMS can be effectively used as a mass analyzer in ICP-MS, particularly with ratioing techniques.
• Further optimization of ion-beam current could extend dynamic range and improve detection limits.
• The simultaneous analysis capability of TOFMS offers advantages for complex elemental and isotopic investigations.