A gas chromatographic peak had a retention time of 730 sec.  The base width obtained from intersection of the baseline with the extrapolated sides of the peak was 6.73 seconds.  If the column was 2,292 cm in length, what was the H in cm/plate?

A young researcher set out to develop a method for quantifying the polycyclic aromatic hydrocarbon (PAH) content in a contaminated soil sample using open tubular gas chromatography. During the initial stages of method development, the researcher was unable to separate the early eluting compounds, anthracene and naphthalene, with baseline resolution. Select the possible modifications the researcher could make to improve the resolution. use a column with a smaller inner diameter decrease the column length increase the stationary phase thickness increase the temperature choose a different stationary phase

In molecular exclusion (size exclusion) chromatography, the molecules have the longest retention times. a) the larger molecules b) the smaller molecules

Describe with illustrations the observed peak for a chromatogram with the following tailing factors (TF): a. TF = 1b. TF > 1c. TF < 1

Internal standard (As , Cs ), analyte with known concentration (Ax , Cx ) In a chromatographic equipment, a solution containing 0.006727 X and 0.008331 M S give peak area of Ax= 2316 and As= 207. To analyze an unknown sample, 5.0mL of 0.008331M S was added to 5.0mL of X, and the mixture was diluted to 50.0mL. This mixture gave a chromatography spectrum with area Ax= 3206 and As= 200. Find Cx.

Two components of a 12-mg sample are adequately separated by chromatography through a column 1.5 cm in diameter and 25 cm long at a flow rate of 0.8 mL/min. What size column and what flow rate should be used to obtain similar separation with a 250-mg sample?

3. Two peaks in a particular gas chromatogram have a retention ratio of 1.25. If this mixture was injected into a gas chromatograph column which had the same column type but a longer column, how would you expect the retention ratio to change?

One method for the quantitative determination of the concentration of constituents in a sample analyzed by gas chromatography is area normalization. Here, complete elution of all the sample constituents is necessary. The area of each peak is then measured and corrected for differences in detector response to the different eluates. This correction involves dividing the area by an empirically determined correction factor. The concentration of the analyte is found from the ratio of its corrected area to the total corrected area of all peaks. For a chromatogram containing three peaks, the relative areas were found to be 16.4, 45.2 and 30.2, in order of increasing retention time. Calculate the percentage of each compound if the relative detector responses were 0.60, 0.78 and 0.88, respectively.

Compare the quantities For a normal phase chromatographic technique: KA > KB Choose A if Polarity of A > Polarity of B B if Polarity of A< Polarity of B C if % both is equal D Cannot Be Determined

4.Consider the peaks for pentafluorobenzene and benzene in the gas chromatogram shown here.  The elution time for unretained solute is 1.06 min.  The open tubular column is 30.0 m in length and 0.530 mm in diameter, with a layer of stationary phase 3.0 μm thick on the inner wall.  a) Measruing the width, w, at the baseline on the chromatogram, find the number of plates for these two compounds b) Use your answer to (a) to find the resolution between the two peaks c) Using the number of plates N=sqrtN1*N2 with the values from (a) calcuate what the resolution should be and compare your answer with the measured resolution in b