The Microscope – Volume 67, First Quarter 2019
IN THIS ISSUE
On the cover
Well-formed, birefringent crystals resulting from a microcrystal test for the drug l-pseudoephedrine using a dilituric acid reagent; crossed polars. See Microcrystal Tests for the Identification of Illicit Drugs: Phencyclidine, Pseudoephedrine, and Psilocin, page 13.
Editorial | Drug Microcrystal Tests Prove Their Relevance in Criminal Justice, Again
Gary J. LaughlinThe Microscope 67:1, p. ii, 2019https://doi.org/10.59082/GRXK6895
Excerpt: This issue of The Microscope journal includes the final installment of original research on microcrystal tests for illicit drugs (see page 13), adapted from McCrone Research Institute’s A Modern Compendium of Microcrystal Tests for Illicit Drugs and Diverted Pharmaceuticals (Microcrystal Compendium). These microcrystal tests, using polarized light microscopy (PLM), can identify most illicit drugs specifically and quickly, usually within a few minutes. They are a reliable check and confirmation of the results and are inexpensive compared to automated instrumental methods.
Calcium Oxalate Phytoliths in Environmental Samples
Russ Crutcher and Heidie Crutcher
The Microscope 67:1, pp. 3–11, 2019https://doi.org/10.59082/PHVW9532
Abstract: Calcium oxalate phytoliths, most commonly whewellite or calcium oxalate monohydrate (CaC2O4·H2O), are a regular part of environmental samples, though generally at low concentrations. They tend to be misidentified as calcite (CaCO3) in environmental samples due to their very high birefringence (0.160) and similar refractive indices (α = 1.490, β = 1.555, and γ = 1.650). Also, being that typical environmental samples are analyzed in a fixed mounting medium, with no ability to roll the particles individually or change refractive index media easily, leads to their misidentification. The crystal habits of calcium oxalate phytoliths are unique, which helps differentiate them from environmental calcite. The crystal habit of a phytolith is the result of chemicals in the cells that promote the growth of specific faces. The result is that the habits available to specific plants are under genetic control to some extent. Some of these faces readily form twinned crystals, which also seems to be under some genetic control. These twins add to the diversity of unique crystal habits. They can be grouped into five general habits: laths, styloids, prisms, druses, and sands. Styloids, prisms, and druses are the most diagnostic of the plant from which they originate. This paper describes the calcium oxalate phytoliths of eight plants: Pseudotsuga menziesii (Douglas fir), Larix occidentalis (western larch), Pinus ponderosa (ponderosa pine), Quercus turbinella (shrub live oak), Rosa nutkana (wild rose), Larrea tridentata (creosote bush), Cercocarpus intricatus (mountain mahogany), and Adenostoma sparsifolium (redshanks). The optical and crystallographic properties of these phytoliths are included with photomicrographs taken with circularly polarized light (CPL) so that all the crystals in the microscope field of view show characteristic interference colors. The setup for CPL and a sodium hypochlorite digestion procedure (wet ashing) for the generation of reference collections are briefly explained in this paper. How calcium oxalate crystals appear in an environmental sample and how to prepare reference materials as needed are also discussed.
Abstract: Calcium oxalate phytoliths, most commonly whewellite or calcium oxalate monohydrate (CaC2O4·H2O), are a regular part of environmental samples, though generally at low concentrations. They tend to be misidentified as calcite (CaCO3) in environmental samples due to their very high birefringence (0.160) and similar refractive indices (α = 1.490, β = 1.555, and γ = 1.650). Also, being that typical environmental samples are analyzed in a fixed mounting medium, with no ability to roll the particles individually or change refractive index media easily, leads to their misidentification. The crystal habits of calcium oxalate phytoliths are unique, which helps differentiate them from environmental calcite. The crystal habit of a phytolith is the result of chemicals in the cells that promote the growth of specific faces. The result is that the habits available to specific plants are under genetic control to some extent. Some of these faces readily form twinned crystals, which also seems to be under some genetic control. These twins add to the diversity of unique crystal habits. They can be grouped into five general habits: laths, styloids, prisms, druses, and sands. Styloids, prisms, and druses are the most diagnostic of the plant from which they originate. This paper describes the calcium oxalate phytoliths of eight plants: Pseudotsuga menziesii (Douglas fir), Larix occidentalis (western larch), Pinus ponderosa (ponderosa pine), Quercus turbinella (shrub live oak), Rosa nutkana (wild rose), Larrea tridentata (creosote bush), Cercocarpus intricatus (mountain mahogany), and Adenostoma sparsifolium (redshanks). The optical and crystallographic properties of these phytoliths are included with photomicrographs taken with circularly polarized light (CPL) so that all the crystals in the microscope field of view show characteristic interference colors. The setup for CPL and a sodium hypochlorite digestion procedure (wet ashing) for the generation of reference collections are briefly explained in this paper. How calcium oxalate crystals appear in an environmental sample and how to prepare reference materials as needed are also discussed.
Microcrystal Tests for the Identification of Illicit Drugs: Phencyclidine, Pseudoephedrine, and Psilocin
Kelly M. Brinsko, Dean Golemis, Meggan B. King, Gary J. Laughlin, and Sebastian B. SparengaThe Microscope 67:1, pp. 13–30, 2019
https://doi.org/10.59082/TNWK8166
Abstract: The Microscope is publishing monographs from McCrone Research Institute’s A Modern Compendium of Microcrystal Tests for Illicit Drugs and Diverted Pharmaceuticals (4th revision: September 13, 2021) , which contains 19 different drugs and their microcrystal test reagents. This issue includes the final installment of monographs, with the following drugs/reagents:
• phencyclidine (PCP)/potassium permanganate• phencyclidine (PCP)/ammonium thiocyanate• pseudoephedrine/dilituric acid• pseudoephedrine/gold chloride• psilocin/trinitrobenzoic acid
The previous set of monographs were published in issue 66:4 (2018): oxycodone with platinum bromide, oxycodone with potassium triiodide (Clarke’s I-KI, No. 1), and oxycodone with sodium carbonate.
Critical Focus | Come Back Plastic, All is Forgiven
Brian J. FordThe Microscope 67:1, pp. 31–42, 2019
https://doi.org/10.59082/WUHX3780
Excerpt: You read the papers, and so do I. They teach us all about the pernicious polymers that are decimating the globe. Our future world, they insist, must be free from the plastic menace. It isn’t just drinking straws, but shopping bags and everything else made from polymers — they must all go. Plastic is suffocating the oceans and polluting the planet. Plastic is bad, and everyone needs to understand that. This is a blanket belief, reminiscent of “four legs good, two legs bad” quoted by Snowball the pig in George Orwell’s Animal Farm and, like all such generalizations, it is hopelessly wrong. Nobody can survive in today’s civilized society without plastics. Many were pioneered by microbiologists, and most of the main groups were discovered by accident. They are not “bad” at all — plastic is of paramount importance. The plastics industry is a mainstay of the modern world and their products are provided because customers prefer them. It is people who cause pollution.
The Microscope Past: 37 Years Ago | Microcrystal Tests and The “Frye Rule”
Walter C. McCrone
The Microscope 67:1, pp. 43–48, 2019
Abstract: The Frye rule states that methods used to support a court appearance must be technically sound as recognized generally in the forensic science community. Microcrystal tests have been used for a century but are generally regarded as subjective. This objection can be eliminated by better crystallographic characterization of the resulting precipitates.
Copyright © 2019 Microscope Publications, Division of McCrone Research Institute. All rights reserved.