Why is it desirable in the method of standard addition to add a small volume of concentrated standard rather than a large volume of dilute standard? An unknown sample of Cu2+ gave an absorbance of 0.262 in an atomic absorption analysis. Then 1.00 mL of solution containing 100.0 ppm (= µg/mL) Cu2+ was mixed with 95.0 mL of unknown, and the mixture was diluted to 100.0 mL in a volumetric flask. The absorbance of the new solution was 0.500. Calculate the concentration of copper ion in the sample.

Why is it desirable in the method of standard addition to add a small volume of concentrated standard rather than a large volume of dilute standard? An unknown sample of Cu2+ gave an absorbance of 0.262 in an atomic absorption analysis. Then 1.00 mL of solution containing 100.0 ppm (= µg/mL) Cu2+ was mixed with 95.0 mL of unknown, and the mixture was diluted to 100.0 mL in a volumetric flask. The absorbance of the new solution was 0.500. Calculate the concentration of copper ion in the sample.

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter20: Molecular Mass Spectrometry

Section: Chapter Questions

Problem 20.9QAP

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