Spreadsheet multiple standard additions

Spreadsheet Summary In Chapter 4 of Applications of Microsoft Excel in Analytical Chemistiy, a multiple standard additions procedure is illustrated. The determination of strontium in sea water with inductively coupled plasma atomic emission spectrometry is used as an example. The worksheet is prepared, and the standard additions plot is made. The unknown Sr concentration and its standard deviation are obtained. 

Spreadsheet Summary In Chapter 12 ot Applications of Microsoft Excel in Analytical Chemistry, we investigate the multiple standard additions method for determining solution concentration. A least-squares analysis of the data leads to the determination of the concentration of the analyte as well as the uncertainty of the measured concentration. 

FtGURE 14-8 Spreadsheet to determine concentration of nitrite by multiple standard additions. 

The standard-addition method can take several forms." The one most often chosen for photometric or spectrophotometric analyses, and the one that was discussed in some detail in Section ID-.1, involves adding one or more increments of a standard solution to sample aliquots. Each solution is then diluted to a fixed volume before measuring its absorbance, lix-ample 14-1 illustrates a spreadsheet approach to the multiple-additions method for the photometric determination of nitrite. 

As many as six or seven components can be determined. Naturally, the reliability of both single and, particularly, multiple component determinations would significantly improve if measurements on the sample were carried out on a large number of different wavelengths. Each such measurement results in an additional independent equation of the variables. The array of these equations can be treated by the spreadsheet Regression function. The improvement will be seen in the smaller standard deviations in the... 

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