Quantitative methods, for

This chapter presents quantitative methods for calculation of enthalpies of vapor-phase and liquid-phase mixtures. These methods rely primarily on pure-component data, in particular ideal-vapor heat capacities and vapor-pressure data, both as functions of temperature. Vapor-phase corrections for nonideality are usually relatively small. Liquid-phase excess enthalpies are also usually not important. As indicated in Chapter 4, for mixtures containing noncondensable components, we restrict attention to liquid solutions which are dilute with respect to all noncondensable components. 

A quantitative method for reporting the ionic composition of a solution that takes into account the greater effect of more highly charged ions (jr). 

Brown and Lin reported a quantitative method for methanol based on its effect on the visible spectrum of methylene blue. In the absence of methanol, the visible spectrum for methylene blue shows two prominent absorption bands centered at approximately 610 nm and 660 nm, corresponding to the monomer and dimer, respectively. In the presence of methanol, the intensity of the dimer s absorption band decreases, and that of the monomer increases. For concentrations of methanol between 0 and 30% v/v, the ratio of the absorbance at 663 nm, Asss, to that at 610 nm, Asio, is a linear function of the amount of methanol. Using the following standardization data, determine the %v/v methanol in a sample for which Agio is 0.75 and Ag63 is 1.07. 

Sandell and KolthofP developed a quantitative method for iodide based on its catalytic effect on the following redox reaction. 

Onc-Factor-at-a-Timc Optimization One approach to optimizing the quantitative method for vanadium described earlier is to select initial concentrations for ITiOz and 1T2S04 and measure the absorbance. We then increase or decrease the concentration of one reagent in steps, while the second reagent s concentration remains constant, until the absorbance decreases in value. The concentration of the second reagent is then adjusted until a decrease in absorbance is again observed. This process can be stopped after one cycle or repeated until the absorbance reaches a maximum value or exceeds an acceptable threshold value. 

The fermentation-derived food-grade product is sold in 50, 80, and 88% concentrations the other grades are available in 50 and 88% concentrations. The food-grade product meets the Vood Chemicals Codex III and the pharmaceutical grade meets the FCC and the United States Pharmacopoeia XK specifications (7). Other lactic acid derivatives such as salts and esters are also available in weU-estabhshed product specifications. Standard analytical methods such as titration and Hquid chromatography can be used to determine lactic acid, and other gravimetric and specific tests are used to detect impurities for the product specifications. A standard titration method neutralizes the acid with sodium hydroxide and then back-titrates the acid. An older standard quantitative method for determination of lactic acid was based on oxidation by potassium permanganate to acetaldehyde, which is absorbed in sodium bisulfite and titrated iodometricaHy. 

Hart, M. and Hart, R., 1989. Quantitative Methods for quality and productivity Improvements, Quality Press. 

Another example of reactivity difference lies in the reaction with silver nitrate. Solutions of the c/s-isomer react with silver nitrate in a few hours at room temperature while the trans-isomer needs refluxing for many hours to remove all the chloride [71, 72, 74], A quantitative method for measuring concentrations of each isomer in mixtures involves reaction... 

In 1967 a paper by Boyle IJ provided a more quantitative method for designing vents for polymer reactors. It was based on reaction rate, heat of reaction, and vapor pressure data. Boyle assumed that the venting of a system can be approximated by sizing to discharge the entire batch contents as a liquid. 

J. Wu, A quantitative Method for Evaluating the Potential of Chemicals for Dioxin Contamination, Richover Science Institute, (1985). 

A quantitative method for weighting canonical forms has been proposed by Gasteiger, J. Sailer, H. Angew. Chem., Int. Ed. Engl., 1985, 24, 687. 

Mikac-Devic Di, Mine M., StankovU H. Quantitative Method for the Determhia-tion of 17-OiaKteioid Fractions by Tbin-Lajier ChiomatOBiaphy , Z. Klin. Chan. Klin. Biochem. Vm, S, 361-363. 

Mikac-Devic, D., Misic, M., Sumkovic, H. Quantitative Method for the DetermuM-tioB of 17-QHwicKnd Fiactions by Thin-Layer Chromaiograpfay , Z KUn. Chem. Klin. Biochem. 1970, 8, 361-363. 

ARTS I c w, HOLLMAN p c H (1998) Optimization of a quantitative method for the determination of catechins in fruits and legumes, Journal of Agricultural and Food Chemistry, 46, 5156-62. 

Fuleki, T. and Francis, F.J., Quantitative methods for anthocyanins. 2. Determination of total anthocyanin and degradation index for cranberry juice, J. Food Set, 33, 78, 1968. 

Fleischer, G., Gerner, K., Kunst, H., Lichtenvort, K., Rebitzer, G. (2001) A Semi-Quantitative Method for the Impact Assessment of Emissions within a Simplified Life Cycle Assessment. International Journal of Life Cycle Assessment, 6(3), 149-156. 

Real-time PCR is a quantitative method for measuring amplicons as they are produced by measuring the increase in fluorescence of a dye added to the reaction mixture.12,104,105 Methods using fluorescent reporters, such as SYBR Green,104,106 TaqMan ,107,108 or molecular beacons,9 collect quantitative data at the time when DNA is in the exponential phase of amplification. 

Williams JC Memphis State University, Memphis, TN Develop and improve quantitative methods for the determination of both metal and nonmetal elements in biological samples National Institute of General Medical Science... 

Goger and Gokcen [19] developed a quantitative method for the determination of miconazole in cream formulations that contain benzoic acid as preservative by second order derivative spectrophotometry. The procedure was based on the linear relationship in the range 100—500 pg/mL between the drug concentration and the second-derivative amplitudes at 276 nm. Results of the recovery experiments performed on various amounts of benzoic acid and the determination of miconazole in cream confirmed the applicability of the method to complex formulations. 

Russell and Rabenstein [43] described a speciation and quantitation method for underivatized and derivatized penicillamine, and its disulfide, by capillary electrophoresis. Penicillamine and penicillamine disulfide were determined by capillary electrophoresis on a capillary (24 cm x 25 pm i.d. or 50 cm x 50 pm i.d. for underivatized thiols) with detection at 357 nm (200 nm for underivatized thiols). The run buffer solution was 0.1 M phosphate (pH 2.3). Detection limits were 20-90 pM without derivatization, and 5-50 pM after derivatization. Calibration graphs were linear from 1 pM to 5 mM thiols. 

The most common types of analyses are the identification test, the quantitative determination of active ingredients or major component, and the determination of impurities. The identification test provides data on the identity of the compound or compounds present in a sample. A negative result signifies that the concentration of the compound(s) in sample is below the DL of the analyte(s). The quantitative method for the major component provides data of the exact quantity of the major component (or active ingredients) in the sample, and a reported concentration of the major component must be higher than the QL. In a Determination of impurities test, one obtains data regarding the impurity profile of a sample, and can be divided into a limit test or quantitative reporting of impurities (see Table 1, which has been modified from Refs. [1] and [8]). 

In order to measure the exact amount of a specific protein (analyte) by IHC signal intensity, a critical requirement is the availability of a standard reference material (present in a known amount by weight) that can be used to calibrate the assay (IHC stain). It is then possible to determine the amount of test analyte (protein) by a translation process from the intensity of IHC signals. In this respect it is helpful to consider the IHC stain as a tissue based ELISA assay (Enzyme Linked ImmunoSorbent Assay), noting that ELISA is used in the clinical laboratory as a standard quantitative method for measuring protein by weight in fluids, by reference to a calibrating reference standard. 

In recent years, several groups have proposed the use of Laser Induced Breakdown Spectroscopy as a technique capable of giving information on the pigment compositions with minimal damage of the artwork. However, until the development of quantitative methods for accurate elemental analysis, the LIBS technique was hardly competitive with other methods for quantitative analysis of the samples. 

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