Lab Deck (Final Exam) Flashcards
Accuracy vs. Precision?
Accuracy: closeness of a value to its true value
Precision: closeness of measurements to each other
What is the Scott Reagent used for?
Detecting cocaine
What is the Marquis Reagent used for?
Detecting meth
Are color tests presumptive or confirmative?
Presumptive
What results do color tests give?
Positive or negative
What are the 3 factors affecting the probability of drugs on currency?
1) Age
2) Denomination
3) Location of circulation
What does the R(f) in R(f) value stand for?
Retention (retardation) factor
R(f) is the ratio of…
Analyte distance travelled to distance solvent front travelled
What is the mechanism of action for paper chromatography?
Nonpolar solvent moves up along polar cellulose in paper via capillary action
Method of separating mixtures into their components based on physical and/or chemical properties of the components
What is chromatography?
What is the stationary phase in paper chromatography?
Paper (polar cellulose)
What is the mobile phase in paper chromatography?
Nonpolar solvent
Physical property of matter relating the mass of an object to its volume.
What is density?
When a substance floats…
Less dense than medium
When a substance sinks…
More dense than medium
When a substance suspends…
Same density as medium
An object immersed in fluid displaces a volume of fluid equal to its value.
What is water displacement, or Archimedes principle?
Comparative method stating that a solid particle will float in a liquid medium of greater density, sink in a liquid of lower density, or remain suspended in a liquid of equal density
What is flotation?
Refractive index is the ratio of…
Speed of light in vacuum to speed of light in medium
True or False: RI will always be greater than 1.
True
If the Becke Line is inside the glass chip, then the RI of the chip is { } than the RI of the surrounding medium.
Greater
What does FTIR stand for?
Fourier-Transform Infrared Spectroscopy
What causes spectral peaks in FTIR?
Functional groups
What is the model of the FTIR machine used?
Perkin-Elmer Spectrum 100 FT-IR Spectrometer
What are the 7 main parts of the GC-MS?
1) Injector port
2) Oven
3) Hydrogen gas
4) Column
5) Interface (connects GC to MS)
6) Ion source
7) Bulb
What do the peaks on a mass spectrum represent?
Fragment ions of varying relative abundance
What is the model of the GC-MS used?
Perkin-Elmer Clarus 600 GC + MS
What does m/z mean?
Mass-to-charge ratio
What is the name of a GC graph?
Gas chromatogram
What is the model of the UV-Vis spectrometer used?
Perkin-Elmer Lambda 35 UV-Vis Spectrometer
What is UV-Vis used for?
Quantitative measurements (e.g. concentration) when the type of compound to be analyzed is known
Shift to a longer wavelength.
What is red shift?
Shift to a shorter wavelength.
What is blue shift?
Why are quartz cuvettes used?
Quartz excels at transmitting a wide range of UV light (190 to 2500 nm)
Why does polarity matter when choosing a solvent?
Polarities have to match so that signals aren’t swamped
Why does solvent cutoff matter when choosing a solvent?
The solvent used must be under the wavelength at which your sample absorbs so that your solvent and sample signals don’t overlap
