Quantitative Analysis or Introductory Analytical Chemistry

1
Quantitative Analysisor Introductory Analytical
Chemistry

• analyze
• "what is it?" (qualitative
  analysis)
• "how much is there? (quantitative
  analysis)

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Quantitative (Chemical) AnalysisChemistry 321

• Dr. Mark Krahling
• Lecture 1/15 Final
• Assignments
• DCH
• Problems
• Web Site
• http//www.usi.edu/science/chemistry/mkrahlin/cour
  ses/CHEM_321/Home.htm

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A Little History'letting measurements speak for
themselves'

• e.g. Lavoisier,
• 18th century
• from Aaron Ihde,
• The Development of Modern Chemistry, 1984

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Applications of Analytical Chemistry

• diagnostic
• environmental
• quality control
• scientific

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Process of Analysis

• Define the information you need
• Select an analysis method
• Obtain a sample 'clean' it up
• Prepare the sample, solutions and standards
• Do the analysis!
• Account for interferences
• Calculate results and estimate reliability
• Convert results to information

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Types of Analysis

• Gravimetric Methods
• measure the mass of an analyte (or something
  chemically equivalent to the analyte)
• Titrimetric (Volumetric) Methods
• measure the quantity of a reagent needed to
  completely react the analyte
• Electroanalytical Methods
• measure the change in the electrical potential,
  current, resistance or charge produced by an
  analyte
• Spectroscopic Methods
• measure the interaction between electromagnetic
  radiation (light, UV, IR, etc.) and the analyte
• Chemical Separations
• separate and measure the analyte of interest by
  chemical means (chromatography)
• Other Methods

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'Doing' Analytical Measurements

• How could we determine the amount of sodium and
  chloride in a saline solution?

•  Some Terms
• Analyte what we are attempting to measure
• Matrix everything else

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Expressing Analysis Results

• percent composition ( composition) - X's 100
• part per thousand (ppt) - X's 1000
• parts per million (ppm) - X's 106
• parts per billion (ppb) - 109
• parts per trillion (ppt) - 1012
• e.g.
• 22 ppm (w/v) lead
• 124 ppb (w/w) atrazine in soil