When you try separating an unknown mixture by normal-phase liquid chromatography with 50% hexane and 50% methyl t-butyl ether, the peaks are too close together.  (not resolved) Should you use a higher or lower concentration of hexane in the next run?

The write-up says “A C18-silica column is used in this experiment, a 0.46 x 15 cm column with 5-µm particles. Equilibrate the column with 20 empty column volumes of 0.010 M phosphate buffer (pH 7.2) at a flow rate of 1.2 mL/min before beginning chromatography.” Show the calculation for how much mobile phase you would use (volume) and how long it will take to equilibrate the column.

Next, 2.00 mL of 9.63 mM S was added to 10.00 mL of a solution of unknown concentration of X, and the mixture was diluted to 25.0mL. Chromatographic analysis of this solution produced peak areas of 4822 for X and 4099 for S. What was the concentration of 5 (in mM) of the 25.0mL solution?

One of the main differences between TLC and column chromatography is the direction in which the mobile phase moves. Group of answer choices True False

thin layer chromatography: What would happen to the Rf value of a compound if you increased the polarity of the mobile phase while using a polar stationary phase?   please help me this question! Thank you a lot

QUESTION 3 What is one disadvantage of using column chromatography?     It is relatively ineffective at separating most organic compounds     The desired compound must be the ≥95% majority compound in the initial mixture for a column to be effective     It is only effective at separating room temperature gasses     It wastes a significant amount of solvent

Chromatography 1. External Standard Method A. Calculate the regression equation and the R-squared value. B. Calculate the concentration of cocaine found in the blood samples of the presidentiables. Which presidential candidate “reliably” tested positive for cocaine?   2. Internal Standard Method >Calculate the concentration of party drug X in the blood samples of the presidential candidates. >Suppose the LOD for party drug X is 0.200 ppm, which of the presidential candidates “reliably” tested for party drug X?