Titration Station
Magnetic Cereal
All GC for ME-E
Antihissssstamines
ISE ISE Baby
The chocolate one
100
How much oxalic acid did you add to your orange juice sample in the VitC experiment?
0.2 g
100
When calculating the mg Fe/g cereal, what was the dilution factor that you needed to account for?
1/10
100
What kind of column is found on the GC-FID?
30m capillary (5%-phenyl)-methylpolysiloxane nonpolar column
100
In what order do the antihistamines elute on the HPLC?
Uracil, Pheniramine, Pyrilamine, Triprolidine, Promethazine, Amitriptyline, Hexanophenone
100
For ISE what can you calculate from the intersection of the Nernstian and Non-Nernstian portion of the curve?
The LOD (limit of detection)
100
When would you want to use an internal standard vs a standard addition method?
Internal standard: corrects for fluctuations in the instrument response
Standard addition: corrects for matrix effects
200
How much potassium iodide solution do you add to the 250 mL erlenmeyer flask?
5 mL
200
How many ppm is 100 mg/L?
100 ppm
200
For GC sample preparation, how much of the previous sample should you use to make the 0.015% standard solution?
60 uL
200
What is eluent A? (i.e. what ratio of chemicals is it)
10:90 MeOH:H2O w/ 5 mM HClO4
200
If you wanted to make 100 mL of 5,000 ppm F- solution in 1 M NaCl, how much NaF and NaCl should you weigh out? (give 3 sig figs for each)
1.11 g NaF and 5.84 g NaCl
200
How long did you boil your chocolate solution in the sample prep experiment?
20 minutes
300
A series of titrations were performed and calculated the concentrations were 0.25M, 0.27M, and 0.24M. What is the RSD? St dev: 0.015
6%
300
A calibration curve of iron standards was created and the linear regression was y = 0.2x+0.02. An unknown sample was tested and it had an absorbance of 0.4 AU. What is the concentration of the unknown iron sample? Answer in ppm, ignore any dilutions.
1.9 ppm
300
For GC, what does the temperature gradient start and end at?
40 - 180 C
300
There are two peaks, A and B. A has a retention time of 5 min with a peak width of 0.5 min. B has a retention time of 4.4 min with a peak width of 0.3 min. What is the resolution?
1.5
300
In mV what is considered a “Nernstian” change between each standard as indicated by the procedure?
~59.0 mV
300
When injecting a sample onto the sample loop of the HPLC, what position should the injector valve be in?
LOAD
400
0.50g of KHP in water was titrated with 22 mL of NaOH to reach the endpoint. What is the molarity of the NaOH solution?
0.11 M
400
How much HCl did you add to digest the cereal sample?
10 mL
400
For GC, what is the mobile phase?
Helium
400
Calculate the number of theoretical plates for an Amitriptyline sample. w1/2 = 0.03 min, retention time = 3 minutes.
400
What is the y axis equation for standard addition? i.e. How do you calculate the y-axis?
400
How many times do you centrifuge your chocolate sample during the step where the majority of the unwanted lipids and nonpolar compounds are extracted?
3!!