Calibration curve determinations

In the absence of Fe +, the membrane is colorless, but when immersed in a solution of Fe + and C, the membrane develops a red color as a result of the formation of a Fe +-bathophenanthroline complex. A calibration curve determined using a set of external standards with known molar concentrations of Fe + gave a standardization relationship of... 

Inject the cleaned-up sample into the GC/MSD or GC/FTD system operated under the same conditions as employed for standardization. Compare the peak areas of the analytical samples with the calibration curve. Determine the concentrations of pyraflufen-ethyl, E-15 (E-1), E-16 (E-2) and E-3 present in the sample. 

Compare the peak areas of the analytical samples with the calibration curve. Determine the concentration of E-2 present in the sample using following equation ... 

Case IV - Analyte Detection (calibration curve determination). If a series of known concentration samples is measured, one can estimate (or verify) both the form and the parameters... 

Recent work evaluated the partition coefficients between 22 different alcohols and nine NAPLs ranging in EACN from chloroform (-15.13) to decane (10) (Dwarakanath 1998). Both plots ofLn (s ) vs. EACN and Ln(kij) vs. EACN provided good agreement for the EACN of each of the nine NAPLs. We have extended these results by measuring ky for four alcohols and 5 neat normal alkanes having EACN from 6 (hexane) to 16 (hexadecane). Next, we measured ky for each alcohol with diesel, and from calibration curves determined the EACN of diesel. 

Weight Percent of MG Analyze the sample using a sample injection of 0.5 pL. From the chromatograms, obtain the peak area of each MG (A,) and of the Internal Standard Stock Solution (Ajs). Calculate the peak area ratio (A/Ajs), and determine the RF for each MG (RF,) from the calibration curve. Determine the concentration, in micrograms per milliliter, of each MG (Cj) in the sample by the equation... 

Calculation Determine the peak areas (response) of interest by automatic integration or manual triangulation. Calculate the response ratio of HQ Calibration Standard and DTBHQ Calibration Standard to Methyl Benzoate Stock Solution. From the calibration curves, determine the concentration ratio of HQ Calibration Standard and DTBHQ Calibration Standard to Methyl Benzoate Stock Solution, and calculate the percentages of HQ and of DTBHQ in the sample by the formula... 

Procedure Transfer 1.00 g of sample into a 150-mL glass beaker, add 10 mL of water, and, while stirring continuously, slowly add 20 mL of 1 A hydrochloric acid to dissolve the sample. Boil rapidly for 1 min, then transfer into a 250-mL plastic beaker, and cool rapidly in ice water. Add 15 mL of 1 M sodium citrate and 10 mL of 0.2 M disodium EDTA, and mix. Adjust the pH to 5.5 0.1 with 1 A hydrochloric acid or 1 A sodium hydroxide, if necessary transfer into a 100-mL volumetric flask dilute to volume with water and mix. Transfer a 50-mL portion of this solution into a 125-mL plastic beaker, and measure the potential of the solution with the apparatus described under Calibration Curve. Determine the fluoride content, in micrograms, of the sample from the Calibration Curve. 

Following Beer s law given in Equation 6.1, for a given wavelength, equivalent concentrations of species with a different molar extinction coefficient will not have an equivalent absorbance. Under these circumstances, the use of calibration curves determined from compounds dissolved in organic solvents and therefore present only in the neutral form will not be appropriate for the determination of the concentration of a species that is ionized. 

From the spreadsheet calibration curve, determine the concentration of fluoride in the unknown solution. Report the results in parts per million fluoride, along with the standard deviation for the three measured samples. 

Unknown. Your instructor will provide you three, or more unknown juices. These may be such products as Hi C drinks, grape drinks, orange juice, and the like. Inject 10-/aL portions of each and record the chromatograms. Several peaks may be obtained. If you have time, run at least two chromatograms on each. From a comparison of retention times, identify the juices that contain vitamin C. Measure the areas of the vitamin C peaks, and from the calibration curve determine and report the concentrations in the unknowns. If two or more chromatograms of the unknowns were run, report the average concentration and the standard deviation if more than two. The vitamin C peak may be partially overlapped by another, fri this case, extrapolate to the baseline and measure the area from the baseline. 

From a comparison of retention times, identify the components of each analgesic. Measure the areas of the aspirin peaks, and from the calibration curve determine and report the concentrations in the various tablets. If there is any overlap of the aspirin peak with another, extrapolate to the baseline and measure the area from the baseline. If two chromatograms were run, report the average concentration. 

In seventies XRD methods gained still greater popularity as the Rietveld [223] program was introdueed. On the basis of the stmeture of all clinker phases the theoretical X-ray pattern can be ealculated, which then is eompared with the diffraction pattern of examined sample and correlated using the least square method. This method needs, however, the calibration curves determination for different clinker types, in order to take into aeeount the matrix influence. 

B) Cumulative mass distribution against elution volume. (Q Molecular mass/elution volume calibration curve, determined by compounding (B) with the fractionation mass distribution [10]. 

As an example, assume that we have the calibration curve in Figure 7.4. The data points for this curve and the equation of the calibration curve determined by linear regression are given in Table 7.4. 

The compliance method measures the compliance of the specimen by unloading it during the experiment. Comparing the measured value with a calibration curve determined on specimens with known crack length, the crack length can be determined. 

Read the apparent concentration of vitamin from the radioactive count obtained from each sample and a calibration curve determined with each batch of samples as described in Section G below. Let this concentration be A mfig B j/liter. Read the apparent concentration of vitamin Bj j in the flask containing sample plus internal standard which was taken through the analysis with each sample. Let this concentration be B m/ug Bij/Uter. Calculate the concentration of vitamin B j in the sample from the expression ... 

Another version of this static headspace chromatography is what has been called by Kolb multiple headspace extraction (MHE) chromatography. This is a multistep injection technique which was alluded to in the Suzuki publication and more openly developed by McAuliffe. The principle of this method is the following. After the first extraction has been made and the aliquot injected, the gas phase is removed by ventilating the vial and re-establishing the thermodynamic equilibrium. The equilibrium between the analyte in the solid or liquid phase and the gas phase will be displaced each time. After n extractions the analyte content in the liquid or solid phase becomes negligible. It is flien sufficient to sum the peak areas obtained for each extraction (which decrease exponentially) and, from an external calibration curve, determine the amount of RS in the substance. 

The melt flow index, melting and crystallization temperatures, and heat of fusion of the samples are shown in Table 1. The difference in the melting point between the reference and the branched samples are caused by the presence of the branching and the reduced crystallinity. The molecular weights are shown in Table 2 based on a calibration curve determined using PMMA standards. 

---