Particle size analysis Sonication

In these case studies, the two model drug compounds formed loosely bound agglomerates that were readily dispersed to their primary particle sizes through the use of sonication during preparation for particle size analysis. 

For particle-size analysis, the fine earth was treated with 3 M HjOj and sonicated (15 min, 15 kHz) coarse, medium and fine sand were retrieved by sieving at 0.25, 0.10 and 0.05 mm, respectively silt was separated from clay by sedimentation after dispersion in 0.01 M NaOH. The pHjj g was measured potentio-metrically (solid/liquid ratio of 1 2.5). Organic C and total N were measured on acidified samples using a Carlo Erba NA1500 analyser. Available P was determined according to Olsen et al. (1954). Effective cation exchange capacity (ECEC) was determined by summation of the cations displaced with 0.2 M BaCl2 and analyzed by atomic absorption with a Perkin-Elmer llOOB spectrophotometer. 

Several instruments are available to perform semiautomated particle sizing by sieving. Modes of agitation include shaking, forced air, and sonic irradiation. The first two types are suited for large sample sizes (10 g or more), and the third type is suited for smaller samples size (< 1 g). These instruments may be interfaced to a balance with software for collection of data by a PC. Particle size analysis by these approaches may require the use of rifflers to generate representative powder sample if the product is not uniform to begin with. 

The application of ultrasound dramatically increases the rate of exfoliation of HxTi2 x/404 yH20 in the presence of aqueous tetrabutylammonium (TBA) hydroxide [130]. The effect of ultra sonication power and processing time on particle size distributions are evaluated. Applied powers of 60-300 W and reaction times of 2-30 min effectively reduce the H-Ti particle size to <100 nm. Both particle size distribution analysis and UV-Vis spectroscopy were used to study the effect of the... 

Particle Size and Crystallinity of Ferrite Crystals The particle size of ferrite crystals was measured because the larger particles are, of course, desirable for their easy separation from a suspension. The size was measured using Laser Diffraction Analysis (LDA). Just before the measurement, the suspension containing a small amount of ferrite crystals was sonicated to disperse the ferrite particles. The particle size distribution of the ferrite crystals formed from 400 mg-Se(IV) solution is shown in Figure 8-1. The distribution has two peaks at nearly 0.2 and 1.8 fim. The median, mode and average diameters were slightly smaller than those obtained from the ferrite crystals formed from only iron(II) sulfate solution. 

For dry colors, 5-10 mg of the sample is dispersed in 5-10 mL of ethanol in a small vial (15 mL size) by sonication for approximately 1 min. One drop of the dispersed sample is then transferred onto a grid on a piece of filter paper floating in the ultrasonic bath. The sonication is continued for another minute. If necessary, additional drops of sample are added to obtain enough samples for analysis. For flush, dispersion or ink samples approximately 1-2 mg is placed in 7 mL of toluene and sonicated to disperse the particles. If the sample bleeds in toluene a weaker solvent such as ether may be used. Small portions of the dispersed sample are added to the grid while continuing to sonicate until adequate amount is collected on the grid for analysis. 

Measurements and Instruments. Particles size was measured by DLS Zetasizer Nano S90. Concentration of samples was 0,5 g/1, each sample was sonicated for at least 10 min before measurement. Elemental analysis was conducted to determine ATRP initiator amount on modified HAP particles. Molecular weights and molecular weights distribution of polymers after etching from particles were measured using GPC MIXED-C PLGel (5pm) methylene chloride was an eluent, at 30°C, with a flow rate 0,8 ml/min, polystyren was used as standard for columns calibration. 

It was discovered that sonication of the mixture during reaction results in PMMA/MWCNT particles with a uniform size distribution, which indicates that size distribution of composite spheres is strongly dependent on proper dispersion of the nanotubes in the reaction mixture, in this case caused by permanent sonication. Again, SEM analysis proved the presence of MWCNT on the surface of MWCNT/PMMA particles (nanotubes strongly and thickly adhered to the surface). 

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