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Membrane Preparation
Published in Takeshi Matsuura, Synthetic Membranes and Membrane Separation Processes, 2020
The flow diagram of the experimental setup is shown schematically in Figure 3.13. A mixture of organic vapor and nitrogen is produced by bubbling nitrogen gas from a porous sintered stainless steel ball immersed in a chosen organic liquid at a temperature slightly lower than the permeation cell temperature. The permeation cell is housed in an isothermal chamber. The permeate side of the membrane is connected to two cold traps followed by a vacuum pump. The permeation of the organic vapor is induced by maintaining its partial pressure on the permeate side lower than the feed side. The membrane-permeated organic vapor is condensed and collected initially in one of the cold traps, and then the cold trap is switched to the other after the steady state is reached. The permeation rate is determined gravimetrically by weighing the sample collected for a predetermined period.
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Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Justine Young, Brandon Zurawlow
Permeation is passage of a fluid into, through, and out of a solid barrier having no holes large enough to permit more than a small fraction of the molecules to pass through any one hole. The process always involves diffusion through a solid and may involve other phenomena such as adsorption, migration, solution, dissociation, and desorption. Permeation rate is a function of the permeant’s concentration, its solubility in the barrier material, as well as the molecule’s physical ability to migrate through the barrier.
Personal Protective Equipment
Published in John F. Rekus, Complete Confined Spaces Handbook, 2018
Permeation is the process by which a chemical passes through a piece of protective material that has no visible holes. It may occur with little or no visible effect on the material, and there may be no obvious indication of degradation. As shown in Figure 10-20, the permeation process takes place in three phases.
Rapid pressure-decay technique for determining the O2 and CO2 permeability coefficients of polymeric films considering the gas compressibility effect
Published in Chemical Engineering Communications, 2023
Murilo Daniel de Mello Innocentini, Carlos Eduardo Formigoni
The term permeation has been generically used to define the different transport phenomena by which molecules and fluids are induced to flow through a solid barrier or membrane. For nonporous or dense homogeneous membranes (term that includes the packaging polymeric materials), permeation occurs by solution-diffusion mechanisms, ruled by Graham’s law, Fick’s law, and Henry’s law (Al-Ismaily et al. 2012; Robertson 2013). The main driving force is the concentration gradient of components between the two sides of the membrane. For the driving force of fluid diffusion, there are two main theories, typically associated by Fick’s law and Darcy’s law. Fick’s law postulates that flow is directed from regions of high concentration to regions of low concentration, with magnitude that is proportional to the concentration gradient. On the other hand, for membranes where the pore structure is relevant, permeation may occur by convective pressure-driven flow, governed by Darcy’s law (Purkait and Singh 2018).
Fentanyl and carfentanil permeation through commercial disposable gloves
Published in Journal of Occupational and Environmental Hygiene, 2020
Lee Ann Greenawald, Kent C. Hofacre, Edward M. Fisher
Fentanyl and carfentanil challenge and collection solutions were analyzed using an internal Battelle liquid chromatograph mass spectrometer-mass spectrometer (LC/MS/MS) method. Specifically, a Waters Acquity Ultra Performance Liquid Chromatograph (UPLC) with a Waters Xevo TQ-XS mass spectrometer and Phenomenex Prodigy ODS-3, 3 µm, 100 A, 100 x 2 mm column operating at 40 °C was used for analysis. Calibration curves covering 1 − 1,000 ng/mL were established. A concentration change of 100 ng/mL in the collection reservoir between consecutive 30 min sample aliquots corresponds to a breakthrough permeation rate of 0.01 µg/cm2/min—the calibration curve covered a range of concentrations one log higher and two logs lower than that associated with this permeation rate. The permeation rate is the rate at which the chemical passes through the glove material at the molecular level; the higher the result, the more chemical passing through (Grainger 2019). Breakthrough is defined as the elapsed time between initial contact of the chemical on one side of the glove material and the analytical detection of the chemical on the other side of the glove material. If breakthrough does not occur, permeation is not measured and reported as the lowest calibration standard (Grainger 2019). Any LC/MS/MS response below the lowest calibration standard were reported as “<1 ng/mL”. Approximately every tenth LC/MS/MS sample was a calibration standard (either 10 or 100 ng/mL) throughout the analysis of the unknown samples. Batches of up to 100 samples were analyzed in one analytical run.
Chemical permeation of similar disposable nitrile gloves exposed to volatile organic compounds with different polarities: Part 1: Product variation
Published in Journal of Occupational and Environmental Hygiene, 2020
Brittany Claire Brown, Anton Dubrovskiy, Aleksandre Roman Gvetadze, Robert N. Phalen
Occupational health and safety professionals rely on chemical permeation data in the selection of CPC (Klingner and Boeniger 2002). Permeation is a process by which a chemical moves through a material on a molecular level, without chemical action (i.e., degradation) or without passing through a physical opening (i.e., penetration), according to Forsberg et al. (2014). During this process, the chemical (1) contacts the exposed surface of the material, (2) absorbs into the material, (3) diffuses within the material, (4) saturates the material, and then (5) desorbs from the opposite, unexposed surface. Two measures are used to define permeation: the breakthrough time (BT) and the steady-state permeation rate (SSPR). The BT is the time, in minutes, that elapses between initial contact of a chemical on one side and its diffusion to the opposite surface of the permeated material, a measure of how soon the chemical crosses the barrier material. The rate of permeation or SSPR is the rate, in µg cm min-1, at equilibrium in which the diffusing chemical travels steadily through the material following breakthrough (ASTM International 2012; Forsberg et al. 2014). The SSPR is a measure of how fast the chemical moves through the material. The resulting desorption of a permeated chemical on an internal surface of a glove can lead to dermal hand exposure. To protect workers from dermal exposure, occupational health, and safety professionals select CPC based on their ability to provide a sufficiently high BT and low SSPR against a hazardous chemical. It must be noted that this does not take into account the toxicity or severity of hazard associated with the chemical, which must also be considered to adequately protect workers.