Origin Unknown

L v ndin. Lavandin, Lavandula hjbrida as a plant species is of recent origin, unknown until the late 1920s. It is a hybrid of two common lavenders, l vandula officinalis and l vandula latifolia. Lavandin is cultivated mainly ia southern France and has become one of the most produced and used natural perfumery materials. The flowering tops of the shmb are used to produce a concrete, an absolute, and a steam-distilled oil the last is by far the most used. Low cost and refreshing odor quaUty allow lavandin to be employed ia a wide variety of perfume appHcations and at high concentrations. Chemically it is comprised of 30—32% linalool (3) and linalyl acetate (1), along with numerous other substances, mosdy terpenic. 

A number of HETP equations were developed other than that of Van Deemter. Giddings developed an alternative form that eliminated the condition predicted by the Van Deemter equation that there was a finite dispersion at zero velocity. However, the Giddings equation reduced to the Van Deemter equation at velocities approaching the optimum velocity. Due to extra-column dispersion, the magnitude of which was originally unknown, experimental data were found not to fit the Van Deemter... 

The essential oil from the oleo-resin of Chinese turpentine (botanical origin unknown) contains a tricyclic sesquiterpene, having the following characters —... 

A 10.0 ml solution containing proteins is reacted with biuret solution and the absorbance is measured as 0.356. Another 10.0 ml sample of the same protein solution is mixed with 5.0 ml of a protein solution known to contain 1.6pgml-1 of protein. The mixture is reacted in the same way as the original unknown and the absorbance is found to be 0.562. What is the concentration of the protein in the sample ... 

Water (origin unknown) entered a remelt fiimace to cause an explosion... 

In standard addition, known quantities of analyte are added to the unknown. From the increase in signal, we deduce how much analyte was in the original unknown. This method requires a linear response to analyte. 

The enzyme attached to antibody 2 is critical for quantitative analysis. Figure 19-14 shows two ways in which the enzyme can be used. The enzyme can transform a colorless reactant into a colored product. Because one enzyme molecule catalyzes the same reaction many times, many molecules of colored product are created for each analyte molecule. The enzyme thereby amplifies the signal in the chemical analysis. The higher the concentration of analyte in the original unknown, the more enzyme is bound and the greater the extent of the enzyme-catalyzed reaction. Alternatively, the enzyme can convert a nonfluorescent reactant into a fluorescent product. Colorimetric and fluorometric enzyme-linked immunosorbent assays are sensitive to less than a nanogram of analyte. Pregnancy tests are based on the immunoassay of a placental protein in urine. 

Quantitative analysis by isotope dilution. In isotope dilution, a known amount of an unusual isotope (called the spike) is added to an unknown as an internal standard for quantitative analysis. After the mixture has been homogenized, some of the element of interest must be isolated. The ratio of the isotopes is then measured. From this ratio, the quantity of the element in the original unknown can be calculated. 

Another valiant on the basic isotope dilution technique is that of double isotope dilution, or valiants thereof, as first proposed by Block and Anker (1948). It is used in reverse IDA where the specific activity of the original unknown radioactive material A cannot be measured for some reason. Hence a second dilution is made to determine the specific activity of the original sample. 

A second 118.0 mg sample of the original is heated vigorously,. whereupon, it loses weight, leaving a residue of only 60.0 mg. However, aqueous solutions of this residue are indistinguishable chemically from solutions of the original unknown. 

Using the information obtained above, calculate the concentration of glucose present in the unknown carbohydrate solution in units of micromoles per milliliter and milligrams per milliliter. Remember that the original unknown carbohydrate solution was diluted for use in this assay. 

Dilute your original unknown carbohydrate solution 1 100 with distilled water to give a total of 1 ml of dilute carbohydrate solution. This diluted sample will be used in the following assay. 

The Americans obviously tried to confirm the authenticity of the letter, because as we have already seen, the document was identified as source and origin unknown . Rauff simply authenticated what he had been given to authenticate. In any case he did not take care to bring the affidavit into accord with the facts. Shortly afterwards he emigrated to Chile, where he remained until his death on May 14, 1984. 

The sample that was analyzed was a fourfold dilution of the original unknown solution. The concentradon of protein in the original solution can be calculated from the dilution factor. 

The standard addition method is often used in cases when it is not possible to obtain suitable blank matrices one example is the analysis of endogenous compounds in body fluids. The approach is to add different weights of analyte to the unknown sample, which initially contains an unknown concentration of the analyte. After the chromatographic analysis, peak areas (or heights) are plotted versus the added concentration. Extrapolation of the calibration plot provides the original unknown concentration of the analyte. A standard addition method that possesses even greater accuracy and precision is obtained if one incorporates an internal standard [48],... 

Most scientihc papers report sufficient information to assign the material of interest to one of subclasses A-C and then to a smaller subclasses. Several specimens could not be classihed because of insufficient information in the original papers. Although the usefulness of the information about PZCs/IEPs of such materials is limited, they are also reported in the present compilation. Such materials are referred to as origin unknown. ... 

Origin Unknown Properties BET specific surface area 10 mVg, crystallite size 227 nm, SEM image available [112]. 

BeO Commercial, Origin Unknown, Water-Washed, and Dried at 110°C... 

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