Direct Detection of Volatile Organic Compounds through Cationization Using ICP-MS/MS.

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Organic Chemistry

Background:

• Volatile organic compounds (VOCs) are crucial indicators in various environmental and industrial applications.
• Traditional methods for VOC detection often involve complex sample preparation and can lead to molecule fragmentation.
• Inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) offers high sensitivity but typically uses harsh ionization conditions.

Purpose of the Study:

• To develop a novel analytical technique for sensitive and selective VOC detection.
• To explore cationization as a soft ionization method within ICP-MS/MS.
• To assess the suitability of various elements for cationization of VOCs.

Main Methods:

• Volatile organic compounds (VOCs) were introduced directly into the collision/reaction cell (CRC) of an ICP-MS/MS instrument, bypassing the ion source.
• The interaction of eight VOCs with 21 different elements was investigated to evaluate cationization efficiency.
• Benzene was used as a model compound to determine cation adduct production ratios ([C6H6 + E]+/E+).

Main Results:

• The cationization approach enabled softer ionization, allowing for the detection of intact VOC molecules.
• Elements with ionization energies between 650 and 900 kJ mol⁻¹ showed the highest cation adduct formation.
• Cobalt, nickel, copper, ruthenium, palladium, and silver were identified as suitable elements for cationization.
• Reduced fragmentation facilitated easier compound detection based on their mass-to-charge (m/z) values.
• The technique was successfully applied to monitor VOCs released from coffee beans.

Conclusions:

• Cationization in ICP-MS/MS provides a soft ionization pathway for VOC analysis.
• This method significantly reduces fragmentation, enhancing the specificity of VOC detection.
• The developed technique shows promise as a rapid analytical tool for VOCs in solid matrices.