ASAP - a Useful Technique for Analyzing Non-Polar Aliphatic Compounds

Noam Tal, Chemistry, Tel-Aviv University, Tel Aviv, Israel

Atmospheric Pressure Solid Analysis Probe (ASAP) utilizes the heated nitrogen desolvation gas to vaporize the sample and a corona discharge for sample ionization.  ASAP analysis generally results in the formation of the parent molecular ion as either the radical cation M+* or the protonated molecule MH+. The formation of the protonated molecule is a result of proton transfer from ionized water clusters in the source. However, if the source is dry, then formation of the radical cation is the primary ionization mechanism. ASAP is ideal for low polarity compounds such as silicones, oil and aliphatic compounds.

Advantages:

• No sample prep required and solids as well as liquids can be analyzed.
• Suitable for complex mixtures such as: crude materials, food, tissue and herbal samples.
• Ideal for high resolution instruments which have the capability of accurate mass and mass-selected fragmentation.
• Good substitute for EI/CI solids probe analysis
• Low cost - compatible with ESI/APCI operations (No source change required)
  

Examples of Mass Spectra of some compounds will be included in the presentation.