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SIMS21, Poland 2017 - Fred Stevie abstract

Fred Stevie oral presentation (OB1-Thu2-1-6)

Quantification of Organic Materials by Ion Implantation

Fred Stevie1, Chuanzhen Zhou2, Stephen C Smith3

1 North Carolina State University - Analytical Instrumentation Facility, 2410 Campus Shore Drive, NC 27695 Raleigh, United States
2 North Carolina State University - Analytical Instrumentation Facility, 2410 Campus Shore Drive, NC 27518 Raleigh, United States
3 Division of Parasitic Diseases and Malaria - Centers for Disease Control and Prevention, 1600 Clifton Road NE, GA 30329 Atlanta, United States

Secondary ion mass spectrometry (SIMS) was initially considered to be a semi-quantitative technique because of as much as five orders of magnitude variation in secondary ion yields over the periodic table for oxygen and cesium bombardment. The use of ion implantation to create standards has made it possible to accurately quantify elements and isotopes in a wide range of inorganic materials.

The development of new ion sources has helped extend depth profiling to organic materials. It is of interest to explore ion implantation to quantify elements and molecular species in organic substrates. Even if the molecular species can be made into a charged beam, the species will disintegrate upon impact with the substrate. However, if the species of interest contains an element that is not present in the substrate, then it should be possible to implant that element into the substrate and make a quantitative determination. In an earlier paper we were able to quantify the insecticide permethrin in mosquito netting, which is high density polyethylene (HDPE). [1] The permethrin negative ion mass spectrum is dominated by Cl- and ion implantation of chlorine provided quantification. This approach has also been successful for the bromine based insecticide deltamethrin in a similar matrix.

We have now explored extension of this method to nitrogen containing insecticides by ion implantation of nitrogen. The species 12C14N- was monitored because of poor yield for N-. Initial results show that nitrogen can be quantified but the detection limit is affected by a low level of nitrogen in the substrate.

This approach may be applicable to other materials, and the use of rare stable isotopes, such as 15N and 18O, may be of value.

[1] C. Zhou, F. A. Stevie, S. C. Smith, J. Vac. Sci. Technol. B34, 03H107 (2016)