A Laboratory Exercise To Demonstrate the Theory and Practice of Analytical Sampling

• Brian A. Logue ^[1] ; Stephanie L. Youso ^[1]
  1. [1] South Dakota State University

     South Dakota State University

     City of Brookings, Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 87, Nº 3 (March), 2010, págs. 316-319
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • In analytical chemistry classes, the importance of gathering a proper sample for analysis of bulk materials is often addressed only briefly or not at all. Although a number of classroom and laboratory exercises have been developed to illustrate factors that impact error introduced by sampling, they generally do not demonstrate the main goal of applying sampling theory for chemical analysis: determining the quantity of sample necessary to achieve a desired error. In this analytical laboratory exercise, students obtain representative samples by initial calculation of the quantity of bulk material to gather to achieve a predetermined sampling error. Students also evaluate some of the properties of a sample that contribute to sampling error. These concepts are introduced in the laboratory using simple surrogate samples and are then applied to a “realistic” scenario that also incorporates gravimetric analysis techniques.