Particulate contaminants, identification

Oil-related analysis encompasses a variety of physical and chemical tests such as viscosity, total acid number and particulate contamination. This is often extended to include the identification of wear debris, as an early warning of component failure, by either spectrographic... 

The first linkage between a microscope and an IR spectrophotometer was reported in 1949 [15]. Today, every manufacturer of IR spectrophotometers offers an optical/IR microscope sampling accessory. The use of optical and IR microscopy is a natural course of action for any solid state investigation. Optical microscopy provides significant information about a sample, such as its crystalline or amorphous nature, particle morphology, and size. Interfacing the microscope to an IR spectrophotometer ultimately provides unequivocal identification of one particular crystallite. Hence, we have the tremendous benefit of IR microscopy for the identification of particulate contamination in bulk or formulated drug products. 

Kamiya et al. [83] evaluated particulate contamination in 199 samples of admixed and un-admixed parenteral nutrition solution bags from 10 hospitals in Japan. Seven samples were used as controls since they had not been mixed with ampoules or vials (un-admixed samples). Size and number of particles were measured using a particle counter, and the identification of elements was carried out by scanning electron microscopy coupled to energy dispersion spectroscopy. The authors collected the residual volume of the samples (10-60 mL) after their usage. The results are presented in Table 40. 

Fourier transform infrared microscopy is the primary infrared technique for structural identification of materials at microquantities. The method is non-destructive and non-invasive. When using a proper transmittance sampling technique and a proper detector, the limit of detection can be as low as the picogram level. In the pharmaceutical industry, FTIR microscopy is used to analyze bulk drugs, excipients, and particulate contaminants. " Recent studies have shown that by coupling FTIR microscopy with GC, HPLC, SFC, or GPC systems, the detection limit of the method is substantially improved. ... 

Although Rs values of high Ks compounds derived from Eq. 3.68 may have been partly influenced by particle sampling, it is unlikely that the equation can accurately predict the summed vapor plus particulate phase concentrations, because transport rates through the boundary layer and through the membrane are different for the vapor-phase fraction and the particle-bound fraction, due to differences in effective diffusion coefficients between molecules and small particles. In addition, it will be difficult to define universally applicable calibration curves for the sampling rate of total (particle -I- vapor) atmospheric contaminants. At this stage of development, results obtained with SPMDs for particle-associated compounds provides valuable information on source identification and temporal... 

Microspectroscopy applies the identification power of infrared spectroscopy to the microscopic realm. Contaminants on printed circuit boards, blemishes in coatings, and other production defects can be isolated in situ and analyzed (see Electronics, coatings). Analysis of flaws that develop during use illuminates the method of failure. Microscopic samples, such as particulates filtered from air, can be analyzed individually. The forensic applications are many paint chips, single fibers, explosive residues, and inks on currency can all be identified nondestmctively (see Forensic chemistry). The structures of layered materials, such as laminated polymer films, are studied via microspectroscopy by cross-sectioning the materials and examining the individual layers edge on (47). 

At the Institute of Environmental Engineering (lEE), Zabrze, Polish Academy of Sciences (lEE PAN) research is performed on mechanics and physico-chemistry of pollutant generation and identification of its origin transport and transformation of pollutants in the environment methods of particulate matter and gaseous air pollutants emission control studies of environmental contamination and many other topics. The scientific equipment at lEE is of a high standard and modem. 

Schwarzbauer J, Franke S (2003b) Identification and quantitation of dinaphthyl sulfones as contaminants in particulate matter of the Elbe river, Germany.Part VI of organic compounds as contaminants of the Elbe river and its tributaries. Chemosphere 51, 973-981. 

Uses of FT-IR microspectroscopy include general characterization of particulate matter, dichroic measurements with polarized light, polymer characterization. semiconductor measurements, the identification of contaminants, as well as forensic, biological, and pharmaceutical applications [157]-11.59). 

Infrared mapping experiments have been extremely valuable since their inception [457]. Applications include obviously any work where the solid sample is very small, as often occurs in identification of contaminants, surface defects, ultrathin deposits, particulates, fibres, fillers, glass fibres, polymer mi-... 

One of the first applications of GC/FT-IR was, in 1979, the identification of alkyl-9-fluorenones in diesel exhaust particulate extracts. Some years later in the EPA laboratory of Athens, GA, USA and then in the EPA laboratory of Las Vegas, GC/ET-IR was applied to identify toxic substances in environmental-sample extracts. In the latter laboratory, the minimum identifiable quantities of 30 priority pollutants and 25 other environmental contaminants were determined. The method was shown to be applicable for the analysis of hazardous waste and industrial wastewater extracts. The gas-phase spectra of 47 compounds of environmental importance were also taken, and their characteristic absorption frequencies and specific absorbances were published. 

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