Use of perfluorocarbons as tracers in chemical compositions

Details Use of perfluorocarbons as tracers in chemical compositions Use of perfluorocarbons as tracers in chemical compositions

1994-04-28

2001-04-10

Smith, Lynette R. F. (Department: 1645)

Chemistry: analytical and immunological testing

Composition for standardization, calibration, simulation,...

C436S056000, C436S124000, C436S125000

Reexamination Certificate

active

06214624

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to tracer-containing chemical compositions. The present invention further relates to a process for using perfluorocarbon tracers in such compositions as a means of determining the possible adulteration of chemical compositions by identifying and quantitatively determining the amounts of such tracers present in such compositions.
2. Description of the Prior Art
The petrochemical industry has traditionally been faced with the problem of distinctively characterizing products for identification purposes. This characterization has typically been accomplished by using various labels or tags. Chlorohydrocarbons have been used to tag hydrocarbon fuel compositions but require that large amounts, from 0.01 mg/l to 10 mg/l, be incorporated for detection. See U.S. Pat. No. 4,141,692. Chlorofluorocarbons, which offer the advantage of having a lower limit of detection, have also been used as tracers. Both chlorohydrocarbons and chlorofluorocarbons are unacceptable though since each is known to deplete the ozone.
Dyes have also been used to tag products such as gasolines, but have proven ineffective for tagging products with a high degree of color. In addition, dyes generally have a high boiling point which makes them unsuitable for many applications.
Radioactive materials function as effective tags since they are detected using noninvasive procedures. Although isotopically labelled compounds are commercially available, the quantity of tracer needed makes them cost prohibitive. In addition, such materials cannot be readily used in commercial products.
It has now been found that very small amounts of one or more perfluorocarbon compounds can be used as tags in chemical compositions to unambiguously identify such compositions and to quantitatively determine the amounts of such tracers in admixture with other materials.
SUMMARY OF THE INVENTION
The present invention relates to tracer-containing chemical compositions which contain a chemical product and at least one perfluorocarbon tracer wherein the total amount of perfluorocarbon tracer present is less than about 800 ppb and each tracer is present in an amount less than about 500 ppb. The present invention also relates to the use of one or more perfluorocarbon tracers in chemical products for identifying such products and quantitatively determining the amounts of such tracers in admixture with other materials.
The tracer-containing compositions of the present invention are valuable because they provide an environmentally acceptable system of tracing products using tracers which are non-toxic, inert and do not interfere with the earth's ozone. In addition, the tracers are ideal for monitoring the contamination, adulteration and/or dilution of products since they are not visually detectable.


REFERENCES:
patent: 4141692 (1979-02-01), Keller
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patent: 4445364 (1984-05-01), Stieff et al.
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patent: 4709577 (1987-12-01), Thompson
patent: 4725551 (1988-02-01), Thompson
Begley et al. “Femtogram Detection of PFC Tracers . . . ” Journal of Chromatography, 445(1988) 119-128.

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