Particle size determination test

However, other analytical procedures, such as dissolution testing for dosage form or particle size determination for drug substance, are required for validation of analytical procedures. The revalidation of an analytical procedure is possible when, in particular circumstances, it could show changes in the synthesis of the drug substance, the composition of the finished product, or the analytical procedure. However, certain other changes may require validation as well. 

Many papers report the fractionation of polystyrene latexes or mixtures thereof, as such commonly available spherical latex standards are an ideal system to test FFF setups or evaluations (for an example, see [362,401]). Recent coupling of Fl-FFF to MALLS enables a very high precision in particle size determinations. One example is shown in Fig. 31, where two Duke standard latex batches of a nominal size of 100 nm were investigated by Fl-FFF/M ALLS, underlining both separation power and resolution. Using traditional techniques such as photon correlation spectroscopy (PCS) and classic Fl-FFF detection, these samples seem to be identical. However, with Fl-FFF/MALLS, the batches could be separated as two discrete size distributions with a peak size that differed by 3 nm. However, it is not stated if a precise temperature control was maintained so that, critically considered, the observed differences could also have their origin in slight temperature... 

ASTM Cl 921-96 Standard test methodfor particle size (sieve analysis) of plastic materials, applicable to particle size determination of plastic materials in powdered, granular or pelleted forms by dry sieving with a lower limit of measurement of about 38 pm, 212... 

Standard tests for measurement of the significant properties of fly ash after investigating many devices for particle size determination, the committee selected the Bahco as the standard instrument [26,27]. 

Preparation of sample Determination of sample weight/volume for density, etc. Reduction of particles size, drying, test for dissolution in solvents compatible with plasma sources... 

Carbon monoxide chemisorption was measured at 25 °C on all catalysts tested. The results were used in calculations of turnover numbers, assuming only rhodium metal atoms chemisorbed CO. While this assumption is naive and probably incorrect (10), results correlated moderately well with rhodium particle size determinations by transmission electron microscopy. 

CEN EN 933-2.1995. Tests for geometrical properties of aggregates — Part 2 Determination of particle size distribution-test sieves, nominal size of apertures. Brussels CEN. 

Jastrebova and his coworkers compared both UPLC and HPLC for the separation and determination of the most common dietary folates (a group of derivatives of folic acid) 5-methyltetrahydrofolate (5-CH3-H4folate), tetrahydrofolate (H4folate), 5-formyltetrahydrofolate (5-HCO-H4folate), 10-formylfolic acid (lO-HCO-folic acid), and folic acid [95], Four alkyl-bonded columns, two UPLC columns—Acquity BEH C,8 and Acquity HSS T3, 100 x 2.1 mm i.d 1.7 pm particle size—and two HPLC columns— Xbridge C,g and Atlantis dl8, 150 x 4.6 mm i.d., 3.5 pm particle size— were tested for this purpose. In respect to the surface chemistry, the Acquity BEH C18 column is similar to the XBridge Cj8 column, while the Acquity HSS T3 column is similar to the Atlantis dl8 column. 

P. H. Emmett, Symposium of New Methods for Particle Size Determination, American Society for Testing Materials, Philadelphia, March 4,1941, p. 95. 

The new method eliminates the need for sampling, particle size determinations (except that of the feed suspension but this is only done once for a whole string of experiments) or flow rate measurements. This makes the tests simpler than the conventional test methods and also capable of being performed by simple, on-line instrumentation and a computer. 

Carmon PC. Symposium on New Methods for Particle Size Determination in the Subsieve Range. Amer Soc Testing Materials, 1941, p 24. 

Tests done in the borrow area are mainly aimed at determining the quality, quantity and dredgeability of the soil. The soil properties (e.g. grading) might change during dredging and therefore not all tests are useful or at least need to be treated with care (e.g. Particle size distribution tests). 

Size. The precise determination of particle size, usually referred to as the particle diameter, can actually be made only for spherical particles. For any other particle shape, a precise determination is practically impossible and particle size represents an approximation only, based on an agreement between producer and consumer with respect to the testing methods (see Size measurement of particles). 

Screening. A 100-g sample of mica is usually used for this test, plus a rack of six Tyler sieves and a pan. The stack of sieves containing the sample is rotated, and after screening, the mica remaining on each screen is weighed and the percentage retained is calculated. A combination of wet and dry screening may also be used to determine particle size distribution of fine mica (<0.147 mm ( — 100 mesh)). 

In order to define the extent of emissions from automotive brakes and clutches, a study was carried out in which specially designed wear debris collectors were built for the dmm brake, the disk brake, and the clutch of a popular U.S. vehicle (1). The vehicle was driven through various test cycles to determine the extent and type of brake emissions generated under all driving conditions. Typical original equipment and aftermarket friction materials were evaluated. Brake relines were made to simulate consumer practices. The wear debris was analyzed by a combination of optical and electron microscopy to ascertain the asbestos content and its particle size distribution. It was found that more than 99.7% of the asbestos was converted to a nonfibrous form and... 

The types of sedimentation encountered in process technology will be greatly affected not only by the obvious factors—particle size, hquid viscosity, sohd and solution densities—but also by the characteristics of the particles within the shiny. These properties, as well as the process requirements, will help determine both the type of equipment which will achieve the desired ends most effectively and the testing methods to be used to select the equipment. 

Particle-Size Distribution This is defined as the relative percentage by weight of grains of each of the different size fractious represented in the sample. It is one of the most important factors in evaluating a screening operation and is best determined by a complete size analysis using testing sieves. 

If it is assumed that explosible dust will be present above the MEC, and equipment design data are not required, explosibility testing forP g, and Kg usually has no direct application. However, minimum ignition energy (MIE) testing should be considered to help determine the likelihood of ignition. Since MIE is extremely sensitive to particle size it is especially important to test a sample that is sufficiently fine to represent the worst credible case. 

In selecting cloths made from synthetic materials, one must account for the fact that staple cloths provide a good retentivity of solid particles due to the short hairs on their surface. However, cake removal is often difficult from these cloths - more than from cloths of polyfilament and, especially, monofilament fibers. The type of fiber weave and pore size determine the degree of retentivity and permeability. The objective of the process, and the properties of particles, suspension and cake should be accounted for. The cloth selected in this maimer should be confirmed or corrected by laboratory tests. Such tests can be performed on a single filter. These tests, however, provide no information on progressive pore plugging and cloth wear. However, they do provide indications of expected filtrate pureness, capacity and final cake wetness. 

HEPA and ULPA filters have been developed. In the CEN EN 1822 1998 test method, the filter s efficiency is determined for the most penetrating particle size (MPPS). Depending on the filter s total level of separation and leakage, the filter is classified as HIO, Hll,.. ., H14 and U15, U16, or U17. HEPA filters are commonly used for inlet air in the pharmaceutical, optical, and food industries. 

All packing materials produced at PSS are tested for all relevant properties. This includes physical tests (e.g., pressure stability, temperature stability, permeability, particle size distribution, porosity) as well as chromatographic tests using packed columns (plate count, resolution, peak symmetry, calibration curves). PSS uses inverse SEC methodology (26,27) to determine chromatographic-active sorbent properties such as surface area, pore volume, average pore size, and pore size distribution. Table 9.10 shows details on inverse SEC tests on PSS SDV sorbent as an example. Pig. 9.10 shows the dependence... 

The comprehensive research program included all facets necessary for the development of these catalysts. Laboratory tests were conducted to determine the necessary catalyst loading, the design operating conditions, the effect of particle size, the effect of various trace constituents on catalyst performance, and finally, resistance of the catalyst to thermal upsets. This paper presents only those findings which have direct sig-... 

The particle-size distribution of two test powders, spherical glass beads and crushed quartz was determined with different types of app (Ref 32), and indicate that the micro-mesh sieve data is in good agreement with those of other methods (Table 6) ... 

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