Calculations Dilution Factors

Calculate the concentration (in igg-1) of lead in the soil sample described above. An accurately weighed (2.1270 g) soil sample is digested in 25 ml of concentrated nitric acid, cooled and then quantitatively transferred to a 100 ml 

What is the concentration of lead in the original soil sample If the absorbance from the digested sample was 0.026, calculate the concentration of lead from the graph and then apply the dilution factor. 

Calculate the concentration (in xgml 1) of lindane in the waste water sample discussed in SAQ 1.2 above. A waste water sample (1000 ml) was extracted into dichloromethane (3 x 10 ml) using liquid-liquid extraction. The extract was then quantitatively transferred to a 50 ml volumetric flask and made up to the mark with dichloromethane. What is the dilution factor  

If the solution was then analysed and found to be within the linear portion of the graph (see SAQ 1.2), the value for the dilution factor would then be multiplied by the concentration from the graph, thus producing a final value representative of the element under investigation. 

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There would be, however, a considerable discrepancy between the model-calculated dilution factor and the dilution factor required if the biospheric C02 input were of comparable size as the fossil C02 input as stated by biologists [43]. For a discussion of this question see also Oeschger et al., [39]. Thirdly, we calculate the 14C dilution corresponding to the CO increase. In 1950, before the nuclear weapon tests, the integrated C02 production amounted to about 10 percent of the preindustrial atmospheric C02 content. If there had been no exchange with other reservoirs, a decrease of the 14C/C ratio by 10 percent would have resulted. Tree-ring 14C measurements indicated, however, a decrease by only about 2 percent. Again we calculate the system dilution. In a first approximation 4 and s are set equal to one and we obtain... 

In the Ebro River basin, calculated dilution factors, that is, the ratios between WWTP effluent and river flows, varied between 3 and 1785. The lowest values were observed in a tiibutaiy, the Arga River, and the largest ones close to the mouth of the Ebro River. Variability of dilution factors was also observed between different seasons, probably because of the continental climate conditions (sparse and irregular precipitation and high evaporation rates) that affect this water basin (Postigo et al., 2010). 

Calculations all dilution factors and calculation parameters should be clearly explained. An example calibration curve should be provided. 

The concentration of analyte in the unknown sample is extrapolated from the calibration curve. To obtain an accurate and precise quantitative value, the optical density (OD) for the sample solutions must fall on the linear portion of the calibration curve. If the sample OD is too high, the sample solution must be diluted until the OD falls within the quantitative range of the assay. The concentration of the analyte in the original sample is calculated by correcting for any dilution factor that was introduced in preparing the sample for application to the microplate. 

The residue, Wr in mg of an identified analyte is calculated using the sample equivalent Cex from Modules E, the dilution factors Tgpc and Fq from Modules GPC and C, respectively, and the concentration Ca from Modules D. The following equation is used ... 

Calculate the dilution factor Fgpc using the following equation ... 

Note The dilution factor Fqpc is required for calculating the content of an identified analyte according to Section 3.1.5. 

In calculating the data a dilution factor of 1/20 has been used for the EPM 797-system. 

The calculation of hazard quotients (HQs) was a useful tool to estimate the hazards that the occurrence of PhACs may pose to aquatic organisms. It was estimated that the overall relative order of susceptibility was algae>daphnia>fish. Results indicated that the reduction of pharmaceuticals concentration after wastewater treatment, as well as the dilution factor once they are discharged into the receiving river waters, efficiently mitigates possible environmental hazards. Nevertheless, risks are expected to be higher in areas with low river flow. 

The fossil C02 brought into the atmosphere does not contain 14C and leads to a 14C dilution. Without exchanges between the atmosphere and the other reservoirs, a fossil C02 input of 10 percent until 1950 would have led to a decrease of the 14C/C ratio by 10 percent. The actually observed reduction of the 14C/C ratio, however, is of the order of 2 percent, i.e., much smaller. This is to be explained by the exchange with the biospheric and oceanic reservoirs. Again a dilution factor D14p <. of the system can be calculated. ... 

Calculation of dilution factors with the box-diffusion model... 

The instrument measurement is the measurement of the solution tested, and the concentration found is the concentration in that solution. What the concentration is in the original, untreated solution or sample must then be calculated based on what the pretreatment involved. Often this is merely a dilution factor. It may also be a calculation of the grams of the constituent from the molar concentration of the solution, or the calculation of the parts per million in a solid material based on the weight of the solid taken and the volume of extraction solution used and whether or not the extract was diluted to the mark of a volumetric flask. Some examples of this follow. Remember that parts per million for a solute in dilute water solutions is in milligrams per liter, while for an analyte in solid samples it is in milligrams per kilogram. Review Chapter 5 for more information about the parts per million unit. 

Dynamic olfactometers dilute the gas by mixing known flow rates of two gases at the same outlet. The dilution factor is calculated from the flow rates. 

Calibrations of each setting of the olfactometer were made in triplicate and in randomised sequence. The dilution factors were calculated as ... 

The theoretical dilution factors were calculated from the calibration graphs supplied with the olfactometer, for operation at 1, 2, 4 and 6><105 N/m2. The graphs plotted were the volumetric ratios of diluting gas odorous air against rotameter readings. These ratios were converted to dilution factors, in line with the values used with the Prosser, by the derivation shown below ... 

In table 1 some results from this study (2) of odour reduction are presented. The thresholds are mean values expressed as log dilution factors. Standard deviations are calculated on the averages of doubled ED-50 values, each value based on the reports of six observers at a time. As can be seen, incorporation of the manure largely reduced the emission of odour from the field. This mainly concerns the injection techniques, which in some cases reduced the odour to the background level. Conventional tillage implements such as a plow or a disc harrow also reduced the odour emission considerably. 

When the second derivative of (5.32) is calculated and set equal to zero, the inflection point of the titration curve is obtained [23, 24, 133, 134). It has been found that the theoretical titration error generally increases with decreasing sample concentration, with increasing value of the solubility product or of the dissociation constant, with increasing value of the dilution factor and with increasing concentration of the interferents. Larger errors are obtained with unsymmetrical titration reactions. The overall error is a combination of these factors the greatest effect is exerted by the sample concentration, a smaller one by the equilibrium constant and the interferents, and the smallest by dilution. To obtain errors below 1%, it must approximately hold that eg, > 10 2 i,K< 10 , < 10 to 10" and r < 0.3. 

The band broadening and the analyte dilution resulting from extracolumn band broadening were compared between the microfluidic chip system and the conventional macro-scale system. For a proper comparison, we calculated the analyte concentration at the peak maximum of the bioactive peaks (Cmax) from E-64 injections in both systems. It turned out that the dilution factor when comparing the concentration at peak maximum with the injected concentration was only 10% higher for the microfluidic chip system in comparison to the conventional macro-scale system. 

The manual procedure for determination of total nitrogen by chemiluminescence involves preparing the standards from a stock solution, diluting the samples, injecting the standards into the combustion furnace for analysis, and calculation of the nitrogen content of the samples. The calculation is based on the signal from the diluted sample compared to the standard curve and the dilution factor for the sample. 

For the specification of the measurand we need a statement of what we want to measure and at the same time a formula for the result which contains all relevant uncertainty sources. The example in the shde describes the calculation of the result of a determination of the amount of cadmium released from ceramic ware under certain conditions. The result depends on the content of Cd in the extraction solution Co, the volume of the leachate Vl, the surface area ay that is extracted and possibly a dilution factor. These parameters are used to calculate the result. But we also have to consider that the acid concentration, the extraction time and the temperature are influencing the result. Since they are not directly involved in the calculation of the result, we add factors with the value 1. But we assume that this value 1 will have an uncertainty as well. 

Correct for soil moisture content as in Method 5.2, Calculation (2), and any other dilution factors. 

Calculation. Ash-free fulvic acid y mg 100 ml is read from the chart. This solution resulted from 10 g air-dry soil in 250 ml solution. Therefore 250 ml solution contains yx 250/100 mg fulvic acid from 10 g air-dry soil, which converts to 25y mg fulvic acid 100 g or 0.025y% air-dry soil. This must be multiplied by any dilution factor before reading the optical density, also converted to percent oven-dry soil (see Method 5.2, Calculation (2)). 

Calculation. There were 20 ml soil in 50 ml of extractant, therefore sample concentration values from the standard graph should be multiplied by 2.5, the results being expressed as mg b nitrate-N calcium sulphate extractable in air-dry soil. Include any extra dilution factors, and, if required, convert to oven-dry soil using the appropriate factor, as in Method 5.2, Calculation (2). 

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