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Usp 23 <788> Particulate Matter in Injections
Published in Thomas A. Barber, Control of Particulate Matter Contamination in Healthcare Manufacturing, 1999
Procedure—Using standard calibrator spheres having a nominal diameter of 15 to 30 μm, prepare a suspension containing between 50 and 200 particles per mL. Degas the suspension by ▀sonicating▄2▀(at 80 to 120 watts)▄5 for ▀about▄230 seconds or by allowing to stand. Properly suspend the particles by stirring gently, and perform five counts on 5-mL volumes of the suspension, using the particle counter 10-μm size threshold. Obtain the mean cumulative particle count per mL. Pipe a volume of this suspension containing 250 to 500 particles into a filter funnel prepared as described for Filtration Apparatus under Microscopic Particle Count. After drying the membrane, count the total number of standard spheres collected on the membrane filter. This count should be within 20% of the mean instrumental count per mL for the suspension.
Settled Dust Methods: History and Discussion
Published in James R. Millette, Steve M. Hays, Settled Asbestos Dust Sampling and Analysis, 2018
James R. Millette, Steve M. Hays
A sample of the Short-Range chrysotile weighing 0.03187 grams was suspended in a solution of 50/50 alcohol (ethyl) and water. The suspension was mixed in a sonic bath for 3 minutes and then poured through a stack of sieves (1000 μm, 500 μm, 106 μm, and 45 μm) placed above a filter funnel which contained a preweighed 0.2 μm pore size polycarbonate filter. The liquid would not flow through all the sieves by gravity. Therefore, suction was applied. A spray bottle of 50/50 alcohol/water was used to try to wash the material through the screens. After filtration, the filter was dried and weighed. The individual screens were examined visually and under a stereo microscope.
Introduction
Published in Jamie Bartram, Richard Ballance, Water Quality Monitoring, 1996
Jamie Bartram, Richard Ballance
Preparation of glass-fibre filter discs Place a filter disc on the filter holder. Assemble filter holder in suction flask apparatus, connect to vacuum source and apply vacuum.Wash the filter disc with three successive 20-ml portions of distilled water. Continue to apply vacuum for 2-3 minutes after the water has passed through the filter. Discard the filtrate.Remove the filter paper from the membrane filter funnel or the Buchner funnel and place it on a supporting surface in a drying oven. If the Gooch crucible/filter combination is being used, place it in the drying oven. The oven should be maintained at 103-105∘C and drying should be continued for at least 1 hour.Cool the filter or Gooch combination in a desiccator and weigh it on an analytical balance.Repeat the cycle of drying, desiccating and weighing until the weight loss between two successive series of operations is less than 0.5mg.Store filter(s) or Gooch crucible(s) in the desiccator until required.
Effects of different external factors on urban roadside plants for the reduction of airborne fine particulate matters
Published in International Journal of Phytoremediation, 2023
Shulei Li, Chen He, Yan Zhang, Li Wang, Yupeng Zhang, Chenhui Wei, Lin Zhang
The collected leaves were immersed in a beaker with distilled water for 5 min and then stirred gently in the beaker with a glass stick. The solutions were filtered through a filtration apparatus equipped with a 47-mm glass filter funnel connected to a vacuum pump onto preweighed filter paper with a bore diameter of 0.45 μm, and an attached membrane with a diameter larger than 0.45 μm was obtained. Then, the filtrate was further filtered through a membrane with a pore size of 0.22 μm, and particles with a size between 0.22 μm and 0.45 μm were obtained. The filtered membranes were dried in an oven for 6 h at 60 °C. After drying, the filter was put into the vacuum drying dish again before reaching room temperature. A precision balance is then used to weigh the weight of the dried filter and recorded as W2. The weight difference of the membranes before and after filtration is the weight of the captured fine particle, which was recorded as W0 (Yu et al.2009).
Approaches for designing and delivering solid lipid nanoparticles of distinct antitubercular drugs
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Mallikarjun Vasam, Rama Krishna Goulikar
To produce nanoparticles by the solvent emulsification evaporation technique, this involves three fundamental phases. In step (I), lipid material is mixed thoroughly with a known volume of organic solvent to form a homogeneous, transparent lipid solution. In step (II), a high-speed homogenizer is used to combine the solution from step (I) with the necessary volume of water to produce a coarse emulsion. In step (III), nanoemulsion is produced by using a high-pressure homogenizer, which turns the coarse emulsion into a nanoemulsion due to the high pressure, hence causing globule fragmentation. To eliminate the traces of organic solvent, the nanoemulsion is held overnight under continuous stirring on a magnetic stirrer or under a hood. As lipid material precipitates in water following organic solvent evaporation, nanodispersion is generated. Filtration using a sintered disc filter funnel separates lipid precipitation in aqueous media. This technique produces nanosized particles and has a high entrapment efficiency [12, 32].
Reduction of traffic-related particulate matter by roadside plants: effect of traffic pressure and sampling height
Published in International Journal of Phytoremediation, 2020
Chen He, Kaiyang Qiu, Richard Pott
To compare the amount of deposited PM on leaves of roadside plant species under different traffic pressures, the mass difference method was used to quantify the captured PM10 and PM2.5 on the leaf surface (Liu et al. 2014). Each sample was dipped in 200 mL distilled water for 5 min and then both sides of leaves were scrub with a non-depilatory brush to ensure all PM on leaf surface dropped into water. Another 200 mL distilled water was used to flush the leaf surfaces three times. The entire 400 mL turbid solution from the last two steps was then weighed and the value was recorded as MST. 50 mL turbid water was taken into a plastic test tube after 5 min stirring, and its weight was recorded as MS50. 50 mL solution was then dried by a vacuum freeze drier (Alpha 1-2 LD plus Entry Freeze Dryer Package, Martin Christ, Australia) for 72 h until all solution in the tube was totally dried. The weight of particles in the 50 mL solution was then recorded as MSP. The rest 350 mL solution was filtrated through a filtration apparatus which was equipped with a 47 mm glass filter funnel connected to a vacuum pump (KNF Neuberger, USA). The first filter paper was a nylon hydrophilic membrane filter with a bore diameter of 10 μm (HNWP04700, Millipore, Ireland). Then the filtration from the last step was filtrated through the extraction filtration apparatus with the second filter paper, of which the bore diameter was 2.5 μm (CAT-1442-047, Whatman Labware Products, UK, 2017). All fiber membranes and filter papers were then dried in a drying oven with a temperature of 60 °C for 4 h until the weight of the membranes and filter paper were constant. All filter papers and fiber membranes were then put in a polytetrafluoroethylene desiccator under constant temperature for 2 h until their temperature reached room temperature to avert further interference during next weighing process. All dried filter paper and membranes were weighed and filter’s weight difference before and after filtration was calculated. The weight difference of fiber membranes was recorded as MPM>10, and the weight difference of filter paper was recorded as MPM2.5–10. Use the following formulas to calculate the amount of captured PM10 and PM2.5 on leaves. All filter papers and membranes used in this test were pre-dried in a drying chamber at 60 °C for 30 min. The PM deposition on leaves of each species was expressed as the average amount of deposited PM on unit leaf surface area.