Single particle and single cell analysis by ICP-MS with pneumatic nebulisation: Comparing sample introduction systems

Area of Science:

• Analytical Chemistry
• Nanomaterial Characterization
• Cellular Analysis

Background:

• Inductively coupled plasma-mass spectrometry (ICP-MS) in single particle (sp) and single cell (sc) modes is crucial for elemental analysis of nanomaterials and cells.
• Pneumatic nebulization is the preferred sample introduction system for ICP-MS.
• Accurate quantitative data in sp- and sc-ICP-MS relies heavily on the precise determination of transport efficiency (TE).

Purpose of the Study:

• To investigate the performance of various commercial nebulizer and spray chamber combinations for sp- and sc-ICP-MS.
• To evaluate the impact of different sample introduction systems on transport efficiency.
• To determine the influence of various sample types on TE measurements.

Main Methods:

• Testing of multiple nebulizer and spray chamber configurations for ICP-MS.
• Utilizing high sample flow rates (0.4 mL/min) with a traditional cyclonic spray chamber.
• Employing specialized total consumption spray chambers (Cytospray and HE-SIS) at optimal flow rates (10 μL/min).
• Determining transport efficiencies using the particle number method with three model suspensions: gold nanoparticles, europium-loaded polystyrene beads, and selenized yeast.

Main Results:

• Higher sensitivities (approximately 5-fold) were achieved with high consumption setups compared to traditional ones.
• Transport efficiencies varied significantly (up to 90%) depending on the nebulizer-spray chamber configuration and the type of model suspension used.
• Observed differences in TE among gold nanoparticles, polystyrene beads, and yeast highlight the critical role of sample-specific calibration.

Conclusions:

• The choice of nebulizer and spray chamber significantly impacts achievable sensitivity and transport efficiency in sp- and sc-ICP-MS.
• Accurate TE determination necessitates the use of a suitable calibrant that matches the sample matrix and particle characteristics.
• These findings are critical for advancing reliable quantitative elemental analysis in nanomaterial and cellular studies using ICP-MS.