Chemistry: analytical and immunological testing – Peptide – protein or amino acid
Reexamination Certificate
1999-12-17
2003-05-06
Soderquist, Arlen (Department: 1743)
Chemistry: analytical and immunological testing
Peptide, protein or amino acid
C356S301000, C442S068000, C442S082000, C442S082000, C442S082000, C442S082000, C436S091000, C436S092000, C436S093000, C436S096000, C436S098000, C436S104000, C436S107000, C436S815000, C436S816000, C436S901000
Reexamination Certificate
active
06558956
ABSTRACT:
I. TECHNICAL FIELD
Generally this invention relates to the field of detecting the use of controlled substances such as illicit drugs and the like. More specifically, the invention involves the field of Raman spectroscopy to accomplishing detection and the sub-field known as Surface Enhanced Raman Scattering. In a less focused sense, this invention relates to a method of detecting substances through the use of a coated surface and spectroscopic techniques. The invention also covers the use of a new coating with a tethered reactive species that chemically binds to an analyte. Through this new technique, the analyte is then spectroscopically analyzed as part of a new chemical species which is the reaction product of the analyte and the reactive species.
II. BACKGROUND ART
The field of sensing controlled substances is an area which has evolved primarily for the public good. As practically everyone knows, drug and alcohol abuse are significant problems for society. In fact, in 1998 the United Nations conducted an international anti-drug conference involving over one hundred nations which are facing this societal challenge. As society attempts to address this problem it has turned to increasingly sophisticated technical analysis to counter the abuser's attempt to hide either the controlled substance or its use. Naturally, the principles of analytical chemistry have been relied upon for their ability to not only detect but to discriminate the presence of a controlled substance in minute amounts. Unfortunately at its present state, the field of detecting controlled substances still has difficulty in both sensing and discriminating the existence of some substances as well as in avoiding false positive indications. This invention provides a solution that greatly expands the techniques and accuracy available for a variety of substances. It also provides a framework under which practical advantages can now be achieved. These advantages range from the seemingly simple ability to provide a single sensor for a variety of drugs as well as the ability to now be able to discriminate between controlled substances and some chemically similar uncontrolled substances. This latter aspect can be significant because in a variety of applications such as Olympic drug testing and the like, it has become difficult to accurately sense and distinguish the difference between certain substances which are legally available for use and those which are truly illegal substances. In a broader sense, the invention also provides an expansion to the principles of analytical chemistry since it may be applied in other areas as well.
The field of analytical chemistry dates back at least to Pliny the Elder (AD 23-79) who first described the use of an extract from gallnuts that turns black in the presence of iron sulfate. This allowed him to determine if copper sulfate was contaminated with iron sulfate. This simple concept of chemical analysis has grown into analytical chemistry which is one of the four disciplines of modern chemistry. Analytical chemistry encompasses a variety of fields such as clinical chemistry, environmental chemistry, geochemistry, and forensic chemistry. The techniques of analytical chemistry have grown from the simple wet chemical analysis discovered by Pliny the Elder to very sophisticated instrumental methods. Early analytical chemistry relied on visual observation of color changes or the precipitation of a compound to quantitate materials. This meant that the sensitivity was often limited to the visual acuity of the chemist. Instruments have largely replaced these visual techniques, since it is possible to electronically detect changes in light intensity and wavelength with vastly superior sensitivity.
The electronic detection of changes in light intensity and its separation into different wavelengths is the basis of the field of analytical spectroscopy. This is an area in which some type of analyte, namely, some substance or chemical which is desired to be studied, is exposed to some wavelength of energy. This wavelength may be a singular wavelength such as a laser often provides, or it may be many different wavelengths. To provide the information desired, the analyte then causes some type of change in that incident energy and thus results in some type of change in intensity of at least one wavelength of energy which is characteristic of the analyte. Thus the wavelength of energy to which the analyte is exposed and the changed signal resulting usually vary. Naturally, the incident energy may be present in a variety of forms as those aware of the wave-particle duality may easily understand. Essentially, however, all that spectroscopy involves is an incident wavelength which is somehow affected by an analyte to result in a changed signal. This signal may be a singular wavelength or may be a broad spectrum of wavelengths of emission or adsorption. Thus, “spectroscopy” as intended here is not intended to be limited to only some type of slit-based instrument, but rather is intended to fully encompass the areas of analytical chemistry in which changes in wavelengths of energy are studied to gain information with regards to an analyte. Conversely, it should be understood that other fields or areas of study which do not involve changed wavelengths have not been viewed as particularly relevant to this field. For example, the areas of chromatography and the like which act to separate substances, immunoassays which transiently bind substances for nonspectroscopic purposes, and the like, have not been viewed as particularly relevant to the fields in which this invention relates.
As mentioned earlier, the field of sensing controlled substances faces a variety of limitations. These range from imperfect discrimination (such as in the Olympic drug testing scenarios) to practical challenges such as the need to have different tests for different substances. When considering spectroscopic techniques, great improvement has occurred through the introduction of a technique known as Raman spectroscopy. Raman spectroscopy was discovered by Sir Chandrasekhara Venkata Raman in the early 1900s who found that different chemicals sometimes caused unique scattering of an incident wavelength of energy. Since the scattering was largely unique to each chemical, the analysis of the specific scattering thus provided information from which specific chemical detection and identification could be achieved. Unfortunately, limits remained even with the introduction of Raman spectroscopy.
In 1976, a new spectroscopic technique was discovered that is sensitive to interfaces. This technique has been coined Surface Enhanced Raman Scattering (SERS). SERS tends to give large enhancements of Raman scattering in the presence of certain prepared metallic surfaces. The SERS technique has been applied to a variety of problems—not only those associated with analytical chemistry—and more recently has been the subject of several publications and patents for analytical chemistry. This technique generally involved some type of attachment of an analyte to a metal surface or to a coating on a metal surface such as gold or silver.
Even in the broader area of general analytical chemistry, initially, the coatings were not tethered to the metal surface. In U.S. Pat. No. 5,326,211 relating to analytical chemistry in general, Carron and Mullen showed that it was possible to coat a surface with a dye that had complexed with a metal ion to serve as a metal ion detector. Again in the broader field of analytical chemistry, Angel was awarded an early patent, U.S. Pat. No. 4,781,458 for the determination of analytes adsorbed directly to metals surface or partitioned onto a coating. Even more recently some publications by Carron and U.S. Pat. No. 5,327,211 disclosed the use of SERS with coatings that contain thiols to tether the coatings to a silver surface. That disclosure specifically addresses the use of SERS coatings on a fiber optic to allow for remote sensing. Carron, et. al, has demonstrated that the coatings mimic separation science coatings and als
Carron Keith T.
Corcoran Robert C.
Santangelo Law Offices P.C.
Soderquist Arlen
The University of Wyoming
LandOfFree
Method and apparatus for detection of a controlled substance does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for detection of a controlled substance, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for detection of a controlled substance will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3081406