This preview shows page 1. Sign up to view the full content.
Unformatted text preview: prepared with certified standard reference material, then this standard can validate the entire analysis Two other important experimental design methodologies exist: 1. Calibration using the method of standard additions. 2. The use of internal standards. Describe in simple terms what these two methodologies are and how they improve an experimental outcome in terms of accuracy and precision. Indicate why the methodology may improve either accuracy or precision. The method of standard additions cancels most matrix effects and can improve the accuracy of an analysis. The impact on precision may be small or negative depending on how the sample dilution affects the analytical signal and how well the analyst implements the pipetting etc. Internal standards (IS) are chemicals added to the sample and standards (and sometimes blank) that provide an instrumental signal that is separable from the analyte signal that is expected to be completely constant in the absence of instrument sensitivity fluctuations. Often times sample introduction fluctuations, such...
View Full Document
- Spring '08