In the table below, record the color that you observe for each spot or component of each spot after the run is completed. For the retention factor, R₁, write in the numerator (top) the number of mm that the spot has moved and in the denominator (bottom) the number of mm that the solvent has moved from the point where the samples were 'spotted. Calculate the Rf vale for each spot or component of each spot. Im having a difficult time finding the Retention Factor for M&Ms by using Salt water and seeing how much each color moves Instructions Coffee filters usually are round, but it's easier to compare your results if the paper is rectangular. So, your first task is to cut the coffee filter into a rectangle. Measure and cut a 2-3/4" by 7" strip from the middle of a coffee filter. This is easily done by folding the filter in half (to make a half-circle) and then folding the half-circle into thirds. Cut along the 13-fold lines and trim the ends to make a rectangle. 2. Using a pencil (ink from a pen would run, so pencil is required), draw a line ¾” from the edge of one end of the paper. 3. Make small pencil dots for as many samples you have along this line, about 1/4" apart. There will be room for about ten dots. Underneath each dot, label the samples with a single letter code (create your own code). 4. If using colored candies, space 6 drops of water (or however many colors you are testing) equally distant on a plate or piece of foil. Position one candy of each color on the drops. Give the color a few minutes to come off into the water. Pick up the candy and eat it or throw it away. 5. Dip a toothpick into a color and dab the color onto the pencil dot for that color. Use a clean toothpick for each color. Try to keep each dot as small as possible. Allow the filter paper to dry, then go back and add more color to each dot, a minimum of three times (up to six is better), so you have lots of pigment in each sample. This process is known as spotting your sample. 6. If using food colorings, dispense a drop of each food coloring onto a plate and spot it on the paper as described above in 5. Also create a mixture of two to three of the food colorings and spot the mixture on the paper. 7. If using markers make as small a dot as possible on the paper with separate markers at each pencil dot. Spot the markers three to six times each on the same dot (as above in 5) to increase the amount of pigment. Just need the sheet looked at. Sample Code Identity of Sample Color of Spot Retention Factor

An analyst was measuring the performance of a HPLC column. The test solute was Toluene (5 µL). The column was a 4.6 mm i.d. column, 150 mm in length and packed with 5 µm C18 particles. The mobile phase was 40/60 water/methanol and the flow rate was 0.80 mL/min. The void time (to) was 1.86 minutes The retention time of the toluene sample was 14.50 min. The standard deviation of the peak was 7.0542 (s). 2a. The mobile phase velocity was? 0.0806 mm/s 0.1344 mm/s 1.344 mm/s 1.344 x 10³ mm/s (i) (ii) (iv) 2b. The number of theoretical plates was? (i) (ii) (iii) (iv) 2c. The height equivalent to a theoretical plate was? 1.041x10³ m 1.015x105 m 9.862x10-6 m 1.186x10¹² m (i) (ii) (iii) (iv) 4802 15210 24705 9848 2d. The reduced plate height was? (i) 2.03 (ii) 1.97 (iii) 7.55 (iv) 2.08 2e. The column was? (i) (ii) Extremely well packed Well packed Poorly packed (iii) (iv) Insufficient information to decide about the quality of the column

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The figure below shows a typical separation of several fat-soluble vitamins by HPLC. The x-axis is retention time in minutes.  From the graph try to estimate retention times for peaks 2 and 3. Retention time peak 2 = Retention time peak 3 = Assume that w1/2 is 0.15 minutes for peak 2 and 0.16 minutes for peak 3. Assume that tm is 2.00 minutes. How much time does gamma-tocopherol spend in the stationary phase? From tr and w1/2 find N for the peak that elutes first.  From tr and w1/2 find the resolution of peaks 2 and 3 Calculate α for these peaks. If the flow rate for the column is 1.2 mL/minute what is the retention volume for peak 4?