Analysis of organic polymorphs. A review

Antarctic pristine environment is threatened by the presence of microplastics that occur in a variety of shapes and sizes, from fibers to irregular fragments. The aim of this study is to assess the abundance, distribution, and the characterization of the microfibers in zooplankton samples found in ocean waters in Admiralty Bay, Antarctica. The samples were collected at five points in Admiralty Bay during the XXIX Brazilian Antarctic Expedition in the austral summer of 2010–2011. A total of 603 microfibers were collected in 60 samples, with an average abundance of 2.40 (± 4.57) microfibers 100 m−3. Microfiber size ranging from ca. 10 to 22 μm in diameter of various lengths and colors (blue, red, black, and clear) was collected and characterized by scanning electron microscopy (SEM) and Raman spectroscopy. Most of these microfibers were entangled in various different zooplankton species and were identified as polymers composed mostly by polyethyleneglycols, polyurethanes, polyethylene terephthalates, and polyamides. The presence of such microfibers may cause the loss of biodiversity in the Antarctic continent, and the results presented herein can contribute to a better understanding of the impact caused by them within the food chain and human health.

Incidence and identification of microfibers in ocean waters in Admiralty Bay, Antarctica

A new approach to forensic analysis with infrared microscopy: Internal reflection spectroscopy

Fourier transform Raman and infrared spectra have been recorded of diazepam (7-chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one) and four compounds with closely related structures. These compounds are all 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-ones and differ only in the nature of the substituent (R) at N-1. The five compounds are nordazepam (R H), diazepam (R CH3), pinazepam (R CH2 CCH), halazepam (R CH2 CF3) and prazepam (R cyclopropylmethyl). Prominent features of the infrared and Raman spectra have been assigned to functional groups of the parent structure and the substituent groups. The spectra of nordazepam suggest that the compound exists as a centrosymmetric cyclic dimer in the solid state. Complete tabulations of the observed wavenumbers of the five molecules are given. The spectra provide a means of identification of these drugs.

Fourier transform Raman and infrared vibrational study of diazepam and four closely related 1,4‐benzodiazepines

Fourier transform Raman spectroscopy and its application for the analysis of polymeric materials

In the past, the usefulness of laser Raman spectroscopy as an analytical technique in industrial laboratories has been greatly reduced by problems of laser-induced fluorescence. One method of circumventing this problem is to use near-infrared excitation coupled with a modified FT-IR spectrometer. In this paper, we report the results of some initial exploratory experiments which indicate that significant fluorescence rejection can be achieved. This fluorescence rejection opens up new areas of application for Raman spectroscopy. The advantages and limitations of FT-Raman spectroscopy are discussed. In addition, some initial experiments are outlined on Fourier transform Raman microscopy using a conventional microscope.

Applications of Fourier Transform Raman Spectroscopy in an Industrial Laboratory

In recent years there has been considerable growth in the use of infrared microscopy as an analytical tool. These applications have focused on the spatial resolving power of the microscope for analysis of small samples or small contaminants or inhomogeneities within a material. The infrared microscope can also serve as a more versatile sampling accessory. Depending on the nature of the material under investigation, diffuse reflectance or true specular reflectance spectra can be recorded from bulk polymeric materials. In either case, useful chemical or functional group information can be obtained in a noninvasive and nondestructive manner. As a further example of the versatility of the infrared microscope, some initial results are presented illustrating its potential use in the study of monomolecular films on aqueous substrates.

F. J. Bergin

Papers

Applications of Fourier Transform Raman Spectroscopy in an Industrial Laboratory

Some Novel Applications of an Infrared Microscope