Measurement total

Methods Giving SO2 and SO3 but that Measure Total Sulfur... 

Figure 9.28 A two-photon (or more) absorption process may be monitored by (a) measuring total, undispersed fluorescence or (b) counting the ions produced by a further photon (or photons). T is a virtual state...

A USDA report indicates that between 1967 and 1988, butter consumption remained stable at 2 kg per capita, margarine dropped from 5.1 to 4.7 kg, and measured total fat intake per day dropped from 84.6 to 73.3 g (14). This study also projects that the reduced consumption of tropical oils is only temporary and will return to former use levels, possibly even higher. One reason for this projected rise in tropical oil consumption is the knowledge of the beneficial effects of medium-chain length acids high in lauric oils. There is a keen interest in omega-3 fatty acids, as well as linoleic acid, contained in fish oils. 

The total phosphoms content of the sample is determined by method AOCS Ja 5-55. Analysis of phosphoUpid in lecithin concentrates (AOCS Ja 7-86) is performed by fractionation with two-dimensional thin-layer chromatography (tic) followed by acid digestion and reaction with molybdate to measure total phosphorous for each fraction at 310 nm. It is a semiquantitative method for PC, PE, PI, PA, LPC, and LPE. Method AOCS Ja 7b-91 is for the direct deterrnination of single phosphoHpids PE, PA, PI, PC in lecithin by high performance Hquid chromatography (hplc). The method is appHcable to oil-containing lecithins, deoiled lecithins, lecithin fractions, but not appHcable to lyso-PC and lyso-PE. 

The microbial assay is based on the growth of l ctobacillus casei in the natural (72) or modified form. The lactic acid formed is titrated or, preferably, the turbidity measured photometrically. In a more sensitive assay, l euconostoc mesenteroides is employed as the assay organism (73). It is 50 times more sensitive than T. casei for assaying riboflavin and its analogues (0.1 ng/mL vs 20 ng/mL for T. casei). A very useful method for measuring total riboflavin in body fluids and tissues is based on the riboflavin requirement of the proto2oan cHate Tetrahjmenapyriformis which is sensitive and specific for riboflavin. 

This is typically accompHshed by cooling the titration solution with ice, determining the blank, and titrating rapidly. Another method utilizes deterrnination of the total peroxide and peracid content by use of a ceric sulfate titration to measure hydrogen peroxide followed by a iodide/thiosulfate titration to measure total active oxygen (60). 

Detergent Methods. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) methods (2), later modified for human foods (13), measure total insoluble plant cell wall material (NDF) and the cellulose—lignin complex (ADF). The easily solubilized pectins and some associated polysaccharides, galactomaimans of legume seeds, various plant gums, and seaweed polysaccharides are extracted away from the NDF. They caimot be recovered easily from the extract, and therefore the soluble fiber fraction is lost. 

Measurement over medium view path (10-25 km) measures total extinction, scattering and absorption unaffected by clouds, night... 

Simple, versatile measures total metal content. Knowledge of interfering effects important. 

Century organic vapour analysers are factory calibrated to measure total organic vapours according to a standard (methane). Since different organic vapours interact with the flame ionization detector (FID) to varying extents, it is vital that the instrument user be aware of the magnitude of the variation in order to obtain the most accurate data. Each user must determine relative responses for the individual instrument. 

Problem 4,10 How many H eclipsing interactions would be present if cyclopentane were planar Assuming an energy cost of 4.0 kj/mol for each eclipsing interaction, how much torsional strain would planar cyclopentane have Since the measured total Strain of cyclopentane is 26 kj/mol, how much of the torsional strain is relieved by puckering ... 

The pressure behavior shown in Figure 4-3 is readily explained in terms of the kinetic theory of gases. There is so much space between the molecules that each behaves independently, contributing its share to the total pressure through its occasional collisions with the container walls. The water molecules in the third bulb are seldom close to each other or to molecules provided by the air. Consequently, they contribute to the pressure exactly the same amount they do in the second bulb—the pressure they would exert if the air were not present. The 0.0011 mole of water vapor contributes 20 mm of pressure whether the air is there or not. The 0.0050 mole of air contributes 93 mm of pressure whether the water vapor is there or not. Together, the two partial pressures, 20 mm and 93 mm, determine the measured total pressure. 

Table 9.4. C N molar ratios (calculated and measured), total C and N content and stable carbon and nitrogen isotope data from bacteria, their growth medium (nutrient broth), and from collagen (infected and non-infected marten bone). The bacteria for inoculation were raised on nutrient broth (nb), with/without additives.

Information is available regarding excretion of endosulfan and metabolites in humans. Blanco-Coronado et al. (1992) measured total endosulfan in the urine of poisoned individuals shortly after poisoning occurred. However, it could not be ascertained whether the urine was a major or minor excretion route. a-Endosulfan, P-endosulfan, and/or metabolites were present in the urine of humans after intentional oral exposure (Boerebomm et al. 1998) and after occupational exposure either with (Arrebola et al. 1999) or without (Vidal et al. 1998) protective clothing. 

Atomic absorption spectrophotometry Flame Flameless Simple, versatile measures total metal content. Knowledge of interfering effects important. 10 = to 10 M 10 to 10 M... 

Potassium dichromate was used as a molecular marker to measure total system volume and plate count (1). The three column sets exhibited the equivalent of approximately 250-300 plates per foot. This was adequate, even with Set I, to give near baseline resolution of an equal weight blend of the 103 nm and 312 nm samples as shown in Figure 2. This Is approximately an 84 1 number ratio. 

The reactor was charged with 37 elastomer which was Insoluble In the chromatographic mobile phase. Thus, the relationship between calculated and measured solids contents should have, and did, differ by at least 37 at low conversions. Expected formation of Insoluble graft polymer would also have Influenced relationship between calculated and measured total solids. 

Amount of soluble polymer generated in this reaction (Figure 9) was only 18-19% solids, which was well below the 29% total solids found after reaction completion. Differences between calculated soluble solids and gravimetrically measured total solids were large, but variable, for all three polymerizations studied. Thus, amount of soluble polymer was not proportional to total solids. However, a good correlation between total solids and the sum of refractometer peak areas for both polymer peaks was obtained. Figure 10. This correlation included all three polymerizations and there was little or no batch bias. 

For the spectrophotometric method, the evolved carbon disulfide is reacted with copper acetate and diethylamine to form a yellow copper complex which can be measured at 435 nm." The recoveries range between 70 and 90%. Reproducibility of this method was improved by reducing the time and the mode of sample pretreatment. Since all alkylenebis(dithiocarbamates) decompose to carbon disulfide by acid degradation, the above analytical methods are not selective. The result is the measured total residues of all alkylenebis(dithiocarbamates) related products. However, this method is recommended as standard method S15 for alkylenebis(dithiocarbamates) by the German Research Association. ... 

The reaction rate was calculated from hydrogen consumption, from pressure drop. As the hydrogen consumption rate was dependent on amount and purity of substrate, catalyst weight and metal content, conversion rate was given (%/min mg Pd), the measured total hydrogen consumption was taken equivalent with 100% conversion. 

In addition to measuring total recombination coefficients, experimentalists seek to determine absolute or relative yields of specific recombination products by emission spectroscopy, laser induced fluorescence, and optical absorption. In most such measurements, the products suffer many collisions between their creation and detection and nothing can be deduced about their initial translational energies. Limited, but important, information on the kinetic energies of the nascent products can be obtained by examination of the widths of emitted spectral lines and by... 

The next step in this study is to test this control algorithm on the actual laboratory reactor. The major difficulty is the direct measurement of the state variables in the reactor (T, M, I, W). Proposed strategy is to measure total mols of polymer (T) with visible light absorption and monomer concentration (M) with IR absorption. Initiator concentration (I) can be monitored by titrating the n-butyl lithium with water and detecting the resultant butane gas in a thermal conductivity cell. Finally W can be obtained by refractive index measurements in conjuction with the other three measurements. Preliminary experiments indicate that this strategy will result in fast and accurate measurements of the state vector x. 

C, excitation at 289 nm, emission observed at 525 nm, degassed films. (l2) Measured total phosphorescence intensity of MBC (arbitrary units) ("I, X y) component of the MBC phosphorescence due to direct absorption of MBC molecules (ltenJ component of the MBC phosphorescence due to energy transfer. 

Interaction with a chemical indicator Can be highly specific, if suitable indicator. Can measure total exposure over time (dosimetry), if a non-reversible reaction is used. Can allow operation at a convenient wavelength, when gas has no convenient absorption in that spectral range. Poisoning can occur, and is easily fouled. Sensitive to groups of chemicals, e.g. acid gases, rather than to a specific gas. May exhibit non-reversible behaviour, which, in many cases, may be undesirable. May need water vapour present, to act as a catalyst, if dry reaction is too slow. 

---