Chapter 8: Sampling, Standardization & Calibration CHE 321: Quantitative Chemical Analysis Dr. Jerome Williams, Ph.D. Saint Leo University
Overview Sampling Standardization Calibration
Sampling Sampling is one of the most important operations in a chemical analysis. Only a small fraction of available sample is used; therefore, it must be representative of the bulk material.
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Sampling Analytical methods distinguished by 1. type of analysis (qualitative vs. quantitative) 2. Sample size 3. Level of the constituents
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Sampling Sampling is the most difficult step in the entire analytical process for it limits the accuracy of the procedure. Particularly true if sample is large and heterogeneous. How do we process the sample?
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Sampling Sampling is one of the most important operations in a chemical analysis. Only a small fraction of available sample is used; therefore, it must be representative of the bulk material.
Sampling Goal Sampling Process = obtain random sample Composition of gross sample and laboratory sample must closely resemble the average composition of the total mass of material to be analyzed.
Sampling Sampling uncertainties (errors) are uniquely different from systematic and random errors. Preparing Laboratory Samples
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Sampling Types of Sampling Methodology Zoning & Quartering Conveyor Belt Technique Automated Sampling Batch (Discrete) Approach Continous Flow Approach