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Intro to Analysis, Spectroscopy, and Chromatography

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Kartei Details

Karten 24
Sprache English
Kategorie Chemie
Stufe Universität
Erstellt / Aktualisiert 06.01.2016 / 24.06.2016
Lizenzierung Keine Angabe
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Define: analyte (1p)

analyte(s): compound(s) of interest in an analytical procedure

Define "analytical chemistry" and the two common categories of it (3p)

Analytical chemistry: measurement of propertie of a substance or system such that information about the chemical make-up of that system is obtained

1. Qualitative analysis: analysis by physical properties without quantitative data (some or all of the constituents of the system in question are identified)
2. Quantitative analysis: the concentration (or mass) of some or all constituents in a system are measured and identified

What are some factors to method selection? (5p)

1. Elemental or molecular in form
2. Organic or inorganic
3. Volatile or non-volatile
4. Low, medium, or high molecular weight
5. Ionic or non-ionic

What are the two most important considerations for method selection? Define them. (2p)

1. Selectivity: ability of the method to discriminate between different atoms/ions/compounds
2. Sensitivity: magnitude of the change in signal that results from an incremental change in concentration

Definte: limit of detection (LOD) (1p)

Limit of detection (LOD): lowest comcentration of a compound that may be statistically differentiated from the background noise

What two ways can you increase sensitivity? (2p)

1. Improve equipment used
2. Reduce the background noise

What are "descriptors" and what is the minimum number of them necessary to make a clear judgement? (2p)

Descriptors: element or term, qualities, that ha s the function of describing or identifying someone or something in particular

At least 2, completely independent descriptors are required to recognize someone from a distance

What does it mean when a presumptive colour test indicates that the object is positive for a certain substance? (1p)

The object is presumed to be positive for the substance, and fails to be excluded from the evidence