Concentration assay

Assay Concentration, ppm Standard deviation, ppm Number of samples... 

Activity Plant Part Assay Concentration Model Result Location Reference... 

With the specific suitable oxidases, lactate, choline and glucose could be assayed. Concentration measurements of these metabolites could be performed over at least two decades wit a detection limit of 10 pM for lactate and choline and 20 pM for glucose. 

Ultrasonic mixture pretreatment time (min) Head assays (%) Tailing assays (%) Concentrate assays (%) % Recovery ... 

For the conversion of (15)-(+)-3-carene approximately 0.045 mg mL ( 1.2 /tm) CPO was incubated in 100 mM citric acid buffer, pH 3.5 with 25 % (v/v) tert-butanol containing 10 him (15)-(+)-3-carene (final assay concentration) and 10 him sodium chloride, sodium bromide or sodium iodide (final assay concentrations) in a 50 mL vessel on a magnetic stirrer (300 rpm) at room temperature. Hydrogen peroxide was added to a total concentration of 10 ruM over a reaction time of 60 min at a rate of 165 /iM min (165 portions every minute). 

COMPOUNDING OF ERRORS. Data collected in an experiment seldom involves a single operation, a single adjustment, or a single experimental determination. For example, in studies of an enzyme-catalyzed reaction, one must separately prepare stock solutions of enzyme and substrate, one must then mix these and other components to arrive at desired assay concentrations, followed by spectrophotometric determinations of reaction rates. A Lowry determination of protein or enzyme concentration has its own error, as does the spectrophotometric determination of ATP that is based on a known molar absorptivity. All operations are subject to error, and the error for the entire set of operations performed in the course of an experiment is said to involve the compounding of errors. In some circumstances, the experimenter may want to conduct an error analysis to assess the contributions of statistical uncertainties arising in component operations to the error of the entire set of operations. Knowledge of standard deviations from component operations can also be utilized to estimate the overall experimental error. 

Analyte Antibody Assay Concentration Detected Referen- ences... 

This study will cover the range of 50-150% of the nominal assay concentration for compound X. Prepare five standard solutions at 50%, 75%, 100%, 125%, and 150% of the nominal assay concentration, and make one injection per preparation. 

The bias of the y intercept must be bias less than or equal to 2.0% of the theoretical 100% assay concentration value. 

The range is derived from the linearity and accuracy of the method and will be demonstrated for compound X over the range of 80-120% of the nominal assay concentration, and for related compounds over the range of 0.1-2% of the related compound in the drug product. 

The antineuritic vitamin. I. The method of assay, concentration of the vitamin with silver under various conditions, and its solubility in certain organic solvents. Ibid., 94, 765 (1932). With G. R. Cowgill and B. H. Klotz. 

If the above assay concentrations are followed exactly, this becomes ... 

In practice, two obstacles limit the ease for switching from one cTnl or cTnT assay to another. First, there is currently no primary reference cTnl material available for manufacturers to use for standardizing their assays. Second, because of the different epitopes recognized by the different antibodies used, assay concentrations fail to agree. While standardization of assays remains elusive, harmonization of cTnl concentrations by different assays has been narrowed from a 20fold difference to a 2- to 3-fold difference. 

It is recommended to test for substrate solubility under the desired buffer conditions. The substrate stock solution can be diluted in the final buffer for the enzymatic reaction to the desired final assay concentration, e.g., 2 pM. After spinning the solution in a centrifuge at moderate speed for approximately 15 min, it should be checked visually for precipitation. 

The HPLC method development requirements using short columns and fast HPLC to determine the assay concentration for each polymorph at the different temperatures are the same as for solubility determination. However, for stability evaluation of the different polymorphs a stability-indicating HPLC method should be used. 

Compounds that increase the assayed concentration of a 2.0 pg/1 digoxin control by 20% at the indicated concentrations were (S272) ... 

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