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18 Cards in this Set
- Front
- Back
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Is the process of collecting a representative sample for analysis |
Sampling |
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Factors that depend on the sampling method |
Chemistry size Physical state |
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What are the treatments for a solid sample |
Homogenization |
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Important factors that affect the sample integrity |
Time temperature humidity level sample acidity oxygen content exposure to light selection of container |
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Three types of sample |
Gas liquid solid |
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Sampling methods |
Sampling bag centrifugation dissolution accelerated solvent extraction |
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This sampling technique to fill a bag with ambient air seal the bag and transport it to laboratory gas can be used directly |
Sampling bag |
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Sample place in tapered centrifugation tube and span at high force and forced to the bottom tube liquid is decanted it is slow in depends on settling rate |
Centrifugation |
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Solid samples of installment without chemical change in organic solids may require acid or base to enhance solvation heat maybe required for some sample |
Dissolution |
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Pressurized liquid extraction . Solid samples placed in sealed container and heated to above its boiling point . Extracted on the light is remove and transferred to vial for further treatment |
Accelerated solvent extraction |
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Types of sample matrices |
Organic matrices inorganic matrices |
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Four types of organic matrices |
Volatile non volatile semivolatile biological samples |
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General principles of sample preparations |
Should not lose any analyte best Chemical form for assay must be used Remove interferences Do not cross contaminate If necessary dilute or concentrate the sample |
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Three different ways to measure the analyte if it contains interfering species |
Using a selective analytical technique perform selective derivatization Remove the analyte from the sample using a separation or suction process |
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The solution processes |
Dry ashing oxidative fusion wet oxidation |
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Requires high temperature and oxygen to convert the sample into more soluble oxide |
Dry ashing |
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A powerful technique for dissolving difficult sample such as refractories |
Oxidative fusion |
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Requires mineral acids and heat and is carried out in open or closed containers with as much heat as can be tolerated by the container |
Wet oxidation |
