Gram determinant

Data given in fimoles per gram, determined by column chromatography (Rogers and Simmonds, 1958). 

National authorities may require that pancreas powder comply with a limit for total viable count of 104 microorganisms per gram, determined by plate count. National authorities may require that pancreas powder comply with the tests for Escherichia coli and Salmonella. 

In addition to the instrumental parameters normally optimized for solution nebulization, the laser ablation technique requires the optimization of the operation of the laser, the volume of the ablation chamber, and the transport distance from the chamber to the plasma. Detection limits reported in the literature indicate that microgram-per-gram determinations are possible. Precision obtained by laser ablation is somewhat degraded when compared to solution nebulization. For a number of different metal samples precisions between 3 and 11% (RSD) are obtained. The linearity of the calibration graphs is typically two or three orders of magnitude. Due to the nature of the laser beam, laser ablation is best suited for area-localized microanalysis. 

In a patent issued to Balthis (212b) a method is described whereby a sample of deionized silica sol is put into an excess of 0.01 IV NaOH solution at 30 C and over a period of 90 min samples of the solution are removed and the amount of monomeric silica is determined by reaction with the molybdic acid reagent. The rate of dissolution of the silica to form monomeric silicate in the alkaline solution was related to A, the specific surface area of the silica (in square meters per gram) determined by other means, by the following equation ... 

Example 12.1 A batch conventional filtration equipment is used to filter a cell culture suspension which has a viscosity of 3.0 cp. The data for fitration (Table 12.1) at constant pressure is obtained with a vacuum pressure of 500 mm HG. The cell solids on the filter at the end of filtration were dried and found to weigh 14 grams. Determine the specific cake resistance, r and the medium resistance Rm- Estimate how long it would take to obtain 5000 liters of filtrate from this ceU broth on a filter with a surface area of 12 and vacuum pressure of 450 mm Hg. The final volume of the cake is found to be 690 ml. 

The present discussion is restricted to an introductory demonstration of how, in principle, adsorption data may be employed to determine changes in the solid-gas interfacial free energy. A typical adsorption isotherm (of the physical adsorption type) is shown in Fig. X-1. In this figure, the amount adsorbed per gram of powdered quartz is plotted against P/F, where P is the pressure of the adsorbate vapor and P is the vapor pressure of the pure liquid adsorbate. 

Bartell and Flu [19] were able to determine the adhesion tension, that is, ysv -7SL. for the water-silica interface to be 82.8 ergs/cm at 20°C and its temperature change to be -0.173 erg cm K . The heat of immersion of the silica sample in water was 15.9 cal/g. Calculate the surface area of the sample in square centimeters per gram. 

The saponiflcatlon equivalent or the equivalent weight of an ester is that weight in grams of the ester from which one equivalent weight of acid is obtainable by hydrolysis, or that quantity which reacts with one equivalent of alkali. The saponification equivalent is determined in practice by treating a known weight of the ester with a known quantity of caustic alkali used in excess. The residual alkali is then readily determined by titration of the reaction mixture with a standard acid. The amount of alkafi that has reacted with the ester is thus obtained the equivalent can then be readily calculated. 

The volume is determined by weighing the water, having a temperature of r°C, contained or delivered by the apparatus at the same temperature. The weight of water, w grams, is obtained with brass weights in air having a density of 1.20 mg/mL. 

The following masses, in grams, were recorded in an experiment to determine the average mass of a U.S. penny. 

A sample of an impure iron ore is believed to be approximately 55% w/w Fe. The amount of Fe in the sample is to be determined gravimetrically by isolating it as Fe203. How many grams of sample should be taken to ensure that approximately 1 g of Fe203 will be isolated ... 

M HNO3. The concentration of Cu and Zn in the diluted supernatant is determined by atomic absorption spectroscopy using an air-acetylene flame and external standards. Copper is analyzed at a wavelength of 324.8 nm with a slit width of 0.5 nm, and zinc is analyzed at 213.9 nm with a slit width of 1.0 nm. Background correction is used for zinc. Results are reported as micrograms of Cu or Zn per gram of FFDT. 

In molecular weight determinations it is conventional to dissolve a measured mass of polymer m2 into a volumetric flask and dilute to the mark with an appropriate solvent. We shall use the symbol Cj to designate concentrations in mass per volume units. In practice, 100-ml volumetric flasks are often used, in which case C2 is expressed in grams per 100 ml or grams per deciliter. Even though these are not SI units, they are encountered often enough in the literature to be regarded as conventional solution units in polymer chemistry. 

The units of these quantities are determined solely by the ordinate, since the abscissa is dimensionless. Example 10.4 verifies that moles per gram are the units for Kc2/Rg. The molecular weight is given by the inverse of the intercept ... 

Faraday s law states that 96,487 coulombs (1 C = 1 A-s) are required to produce one gram equivalent weight of the electrochemical reaction product. This relationship determines the minimum energy requirement for chlorine and caustic production in terms of kiloampere hours per ton of CI2 or NaOH... 

Characterization. When siHca gel is used as an adsorbent, the pore stmcture determines the gel adsorption capacity. Pores are characterized by specific surface area, specific pore volume (total volume of pores per gram of solid), average pore diameter, pore size distribution, and the degree to which entrance to larger pores is restricted by smaller pores. These parameters are derived from measuring vapor adsorption isotherms, mercury intmsion, low angle x-ray scattering, electron microscopy, gas permeabiHty, ion or molecule exclusion, or the volume of imbibed Hquid (1). 

The sfe of chlorpyrifos methyl from wheat followed by on-line Ic/gc/ecd has been investigated (93). Extraction profiles were generated to determine the maximum analyte recovery and the minimum extraction time. Using pure CO2, a 65% recovery of chlorpyrifos methyl spiked onto wheat at 50 ppb was reported. When 2% methanol was added to the CO2, the recovery from a one gram sample averaged 97.8% (n = 10, 4.0% RSD). 

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