EXTENDING SIFT-MS TO DETECTION OF SEMI-VOLATILES ON SURFACES

Significance of the Topic

Rapid and sensitive detection of semi volatile organic compounds on surfaces is essential for security screening customs inspection agricultural monitoring and quality control in the food industry

Objectives and Study Overview

This study evaluates the extension of Selected Ion Flow Tube Mass Spectrometry to surface swab analysis of explosives taggants narcotics precursors pesticides and food taint compounds The aim is to establish linearity sensitivity and practicality of the swab desorber inlet coupled to SIFT MS instrumentation

Methodology and Used Instrumentation

Samples of target compounds were prepared in dichloromethane and spiked onto swabs after which the solvent was evaporated at ambient conditions A custom swab desorber inlet was developed to introduce desorbed vapors into the flow tube for ionization Reagent ions H3O plus NO plus and O2 plus were applied via a Syft Technologies Voice200 SIFT MS instrument enabling ultra soft controlled ion molecule reactions with analytes

Results and Discussion

Linear calibration curves were achieved across all compound classes with detected concentrations corresponding to sub to low nanogram quantities on swabs Detection limits consistently fell into the low nanogram range Key findings include

• Explosives and taggants such as 24 dinitrotoluene and 23 dimethyl 23 dinitrobutane demonstrated strong linear response up to 120 ng
• Narcotics and precursors including pseudoephedrine and phenyl 2 propanone exhibited reliable quantitation and rapid analysis
• Pesticides represented by 24 D methyl ester and malathion as a surrogate for CWA VX showed clear detection at minimal loadings
• Food taint compounds like 246 trichloroanisole and 246 tribromoanisole were detected at levels relevant for quality control

Benefits and Practical Applications

SIFT MS with a swab desorber offers higher selectivity than ion mobility spectrometry due to instant switching among three reagent ions Mass spectrometric detection yields real time results without sample preconcentration This approach is well suited to homeland security customs agriculture food and environmental monitoring applications

Future Trends and Possibilities

Ongoing development of a negative reagent ion source is expected to improve selectivity especially for nitrated explosives Future work may expand libraries of surface bound semivolatiles integration with portable platforms and automated sampling protocols

Conclusion

The combination of a swab desorber inlet and SIFT MS enables rapid sensitive and selective trace analysis of a broad range of semivolatile compounds on surfaces This technique holds promise for diverse security forensic and quality control tasks

References

Prince BJ Milligan DB McEwan MJ Rapid Commun Mass Spectrom 24 1763 1769 2010
Smith D Spanel P Mass Spec Rev 24 661 700 2005