Cooled sample introduction probe for liquid secondary ionization mass spectrometry.

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Physical Chemistry

Background:

• Fast atom bombardment (FAB) and liquid secondary ionization (LSI) mass spectrometry are powerful analytical techniques.
• The duration and quality of spectra in these methods can be limited by the volatility of matrix materials.
• Existing methods often face challenges with sample stability and the range of applicable matrices.

Purpose of the Study:

• To design and evaluate a cooled sample introduction probe for FAB and LSI mass spectrometry.
• To investigate the impact of in situ matrix cooling on spectrum duration and sensitivity.
• To explore the feasibility of using a broader range of matrix materials with the cooled probe.

Main Methods:

• Development of a novel cooled sample introduction probe for the ion source.
• Application of the probe to FAB/LSI mass spectrometry using various volatile matrix materials (e.g., sulfolane, thioglycerol, tetraglyme).
• Comparative analysis of spectral data obtained with and without probe cooling (target temperature: 9 +/- 1 °C).

Main Results:

• Cooling volatile matrix materials in situ significantly increased the duration of sample spectra by a factor of approximately 10.
• The cooled probe enabled the use of a wider array of matrix materials, previously unsuitable due to volatility.
• An example spectrum of a complex carbohydrate (peracetyl [Glu(beta 1----3)]7 Glucitol) in tetraglyme demonstrated excellent quality with characteristic cleavage peaks, lasting 10 times longer under cooled conditions.

Conclusions:

• The cooled sample introduction probe effectively enhances FAB/LSI mass spectrometry performance.
• In situ matrix cooling provides a substantial increase in integrated sensitivity and spectral acquisition time.
• This technological advancement broadens the scope of applicable matrices and improves the analysis of challenging samples.