The Microscope – Volume 63, Second Quarter 2015
IN THIS ISSUE
On the cover
These feathery crystals are the result of a microcrystal test for cocaine using a platinum chloride reagent with acetic acid. Photomicrograph taken between crossed polars with a Red I compensator. See Editorial: Quick, Reliable Microscopical Tests for Identifying Illicit Drugs on the following page. (Photo courtesy of McCrone Research Institute)
Editorial | Quick, Reliable Microscopical Tests for Identifying Illicit Drugs
Gary J. LaughlinThe Microscope 63:2, p. ii, 2015https://doi.org/10.59082/PLCZ4950
Excerpt: The last several years have been busy and exciting for researchers at McCrone Research Institute. They have been developing a series of microcrystal tests that forensic scientists can use with light microscopy to accurately identify trace amounts of illicit narcotics and diverted prescription drugs in the crime laboratory.
Development of a Microcrystal Test for the Detection of Clonazepam
Danielle Silletti
The Microscope 63:2, pp. 51–56, 2015https://doi.org/10.59082/OQDB5730
Abstract: Microcrystal tests are used as analytical techniques for distinguishing certain drugs in the forensic sciences. While there are some drugs, such as cocaine and heroin, with validated microcrystal tests, other classes of drugs, e.g. the benzodiazepines, lack such microcrystal tests. The goal of this research is to optically characterize and develop a microcrystal test that could be used to detect clonazepam. Clonazepam is a benzodiazepine drug that is sold under the trade name Klonopin. It is known for its sedative-hypnotic properties and has therapeutic uses as an anticonvulsant and anxiolytic. Benzodiazepines have been abused for these sedative effects and are known for their use in drug-facilitated sexual assaults. A microcrystal test was developed that is able to detect clonazepam in pharmaceutical preparations at all current dosages. The test involves the dissolution of microgram quantities of clonazepam in acetone or chloroform and the addition of a 10% platinum chloride aqueous solution. The presence of clonazepam is indicated by the formation of rosettes made of colorless, blunt-ended rods. No other drug is known to exhibit the same reaction with these reagents, making this microcrystal test a viable option in forensic analyses.
Abstract: Microcrystal tests are used as analytical techniques for distinguishing certain drugs in the forensic sciences. While there are some drugs, such as cocaine and heroin, with validated microcrystal tests, other classes of drugs, e.g. the benzodiazepines, lack such microcrystal tests. The goal of this research is to optically characterize and develop a microcrystal test that could be used to detect clonazepam. Clonazepam is a benzodiazepine drug that is sold under the trade name Klonopin. It is known for its sedative-hypnotic properties and has therapeutic uses as an anticonvulsant and anxiolytic. Benzodiazepines have been abused for these sedative effects and are known for their use in drug-facilitated sexual assaults. A microcrystal test was developed that is able to detect clonazepam in pharmaceutical preparations at all current dosages. The test involves the dissolution of microgram quantities of clonazepam in acetone or chloroform and the addition of a 10% platinum chloride aqueous solution. The presence of clonazepam is indicated by the formation of rosettes made of colorless, blunt-ended rods. No other drug is known to exhibit the same reaction with these reagents, making this microcrystal test a viable option in forensic analyses.
Analysis of Vermiculite for Asbestos and Screening for Vermiculite from Libby, Montana
James R. Millette and Steven ComptonThe Microscope 63:2, pp. 59–75, 2015
https://doi.org/10.59082/AOLI8955
Abstract: There is general agreement that a negative finding using the usual bulk microscope analysis for building materials without any pre-treatment of the vermiculite is not reliable. Preparation procedures involving sedimentation, grinding and total matrix reduction with acid/base dissolution have been used to improve the ability to find asbestos if present in vermiculite ores and products. This article contains information on most of the available methods for vermiculite analysis based on an extensive review of published articles, government reports and other documents. The limited data in the published articles concerning the major vermiculite sources in the Enoree district in South Carolina; Louisa County, Virginia; Palabora, South Africa; and Xinjiang Province in China strongly suggest that commercially available non-Libby vermiculite is not contaminated with amphibole asbestos to the extent of the vermiculite from Libby, Montana. Differentiating Libby vermiculite insulation from other commercial sources can be done reliably and inexpensively with a routine chemical barium test as long as the insulation sample is not a mixture of Libby vermiculite and other materials. A qualitative transmission electron microscopy (TEM) analysis of a filtration of the fibers suspended in water from a sample of vermiculite attic insulation (VAI) that was prepared using the sedimentation procedure appears to be a reliable method of confirming Libby vermiculite.
Critical Focus | Forensic Science: Peering Down a Blind Alley
Brian J. FordThe Microscope 63:2, pp. 77–88, 2015
https://doi.org/10.59082/PEUP2114
Excerpt: Guess: Which character in fiction is the most widely portrayed on the screen? Names flood the mind, from Abraham Lincoln to Zeus, but it is actually Sherlock Holmes. Not a celebrity or a mighty ruler, not even a real person; it is that doyen of forensic investigators who is the most frequently portrayed character across the world of film and television. There is a similar surprise when we look at the kind of television most people watch. Is it humor? Reality shows? It is actually forensic science. The annual survey by the Eurodata TV Worldwide organization in 2012 said that “CSI: Crime Scene Investigation” was the most-watched show in the world. At the 52nd Monte Carlo Television Festival in June 2012, Ted Danson came to collect the award. He would have had a terrific time: One of my television documentaries was once nominated for a minor award, and even that provided an unforgettable day. No, of course our trivial production didn’t win anything, but I soon discovered that winning wasn’t crucial — being nominated was enough for the producers. Everywhere you look, you see films that were “nominated” for an award that they didn’t win. You just enjoy the occasion and the French hospitality while savoring the fabulous food.
The Microscope Past: 40 Years Ago | A Schlieren Eyepiece
J. Dodd and W.C. McCrone
The Microscope 63:2, pp. 89–91, 2015Originally published in The Microscope, Vol. 23, Second Quarter, 1975.
Introduction: A schlieren, or dispersion staining, microscope operates by blocking out the zero-order rays where they form an image of the light source. Index of refraction gradients or thickness variations in the sample then deviate some of these zero-order rays, causing them to contribute to the illumination at the image plane.
The image of the light source is normally found at the back focal plane of the objective. This is an awkward place to insert diaphragms, etc. Nevertheless, commercial dispersion staining objectives of moderate N.A. are available.
High N.A. objectives cannot easily be adapted to dispersion staining because the back focal plane of these objectives is well inside the glass. This is an unfortunate limitation to an otherwise powerful method of particle identification since it denies the full resolution range of the instrument to the user..
Afterimage | d-Amphetamine with Gold Chloride
McCrone Research Institute
The Microscope 63:2, p. 96, 2015
This image shows the results of a microcrystal test for the drug d-amphetamine using gold chloride in a phosphoric acid reagent. The test was performed by placing 2 PPP (approximately 0.2 mg) of d-amphetamine on a microscope slide with 10 μL of 40% sodium hydroxide. 5 μL of reagent was then deposited on a coverslip, which was inverted over a glass-ring reaction chamber. These crystals formed after the hanging drop was allowed to sit for 15 minutes; it was then turned over and exposed to air. (Photo courtesy of McCrone Research Institute)
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