Quantitative analysis calibration graph method

Quantitative Analysis Using Calibration Graph Method... 

Quantitative analysis demands that an analytical measurement can be accurately and reliably related to the composition of the sample in a strict proportionality (p. 2). The complexity of relationships, especially for instrumental techniques, means that the proportionalities need to be practically established in calibration procedures. For a typical simple calibration, a range of standards is prepared containing varying amounts of the analyte. These are then analysed by the standard method and a calibration curve of signal us amount of analyte is plotted. Results for unknowns are then interpolated from this graph (Figure 2.7). An important convention is... 

The advantages of CC in ultra trace analysis are shown to be unmistakable. The quantitative reliability of the method was demonstrated by the extension of a calibration graph for phenol to two decades of concentration more when compared with conventional chromatography. A considerable improvement of the signal-to-noise ratio can be achieved in a relatively short time. The method offers excellent prospects for ultra trace analysis in cases where preconcentration of the solute fails. 

Nie et al. used a flow injection chemiluminescence method for the determination of dipyridamole in Persantin tablets [51]. A flow injection analysis system equipped with a chemiluminescence detector was used. Sodium hypochlorite was used as a chemiluminescent substance, and Triton X-100 was used as an enhancer of the chemiluminescence reaction. Sample solutions (pH 4-6) was injected into 0.2% Triton X-100 and treated with 0.5% sodium hypochlorite, and the chemiluminescence intensity then measured. The calibration graph was linear from 0.04 to 10 pg/mL of Persantin tablets (as its active ingredient dipyridamole), with a detection limit of 11 ng/mL. Recoveries were quantitative and the relative standard deviation ( = 3) was 2.7%. The method has been used to determine Persantin in injection and tablets, and the results obtained using this method agreed with those obtained by the Chinese Pharmacopoeial method. 

Similar to other quantitative analytical approaches, the area under the spectral lines is proportional to the number of Mossbauer atoms detected. Practically, in one approach, a calibration graph of the area value of a series of external analogous samples with known concentrations would be constructed and compared with that of the unknown samples. In another approach a graph of the area value of unknown sample added with analogous samples with a series of known concentration can be drawn for calibration. Both approaches are common methods employed in instrumental analysis. 

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