LIQUID CLUSTER SECONDARY ION MASS SPECTROMETRY: SIGNAL ENHANCEMENT THROUGH GLYCEROL DROP ADDITION

Tim M. Brewer, Christopher Szakal, and Greg Gillen

The feasibility of direct deposition of glycerol onto organic thin films to provide enhanced secondary ion signals is investigated by C₆₀⁺ cluster secondary ion mass spectrometry (SIMS). Glycerol drops were deposited on various organic thin films and the organic molecules were rapidly incorporated into the drop via diffusion and convective forces. The resulting glycerol/analyte drops were then probed with fullerene primary ions under dynamic and static SIMS conditions. High primary ion beam currents were shown to aid in the mixing of the glycerol drop, thus replenishing the probed area and sustaining secondary ion yields. Integrated molecular secondary ion signals for tetrabutylammonium iodide and cocaine in the glycerol drops compared to an analogous area on the surface were enhanced by several orders of magnitude (> 100x). These molecules were chosen because the molecular ions are formed through separate ionization pathways. Once the analyte of interest is incorporated into the glycerol microdrop, the solution chemistry can be tailored, with examples shown for cyclotrimethylenetrinitramine (RDX) chloride adduct formation. Additionally, depositing localized glycerol drops may enhance analyte secondary ion count rates to high enough levels to allow for site-specific chemical maps of molecules in complex matrices such as biological tissues.

CATEGORY: Chemistry

Mentors Name: Greg Gillen

Division, Laboratory 837.05

Room B 235, Building 217 Mail stop 8371

Tel: 301-975-3926

Fax: 301-216-1134

Email: timothy.brewer@nist.gov

Is your mentor a Sigma Xi Member?     No