Consider the peaks for heptane (14.56 min) and p-difluorobenzene (14.77 min) in the chromatogram. The column is 30.0 m long. (a) Measure w1/2 for each peak and calculate the number of plates and the plate height for each. (b) From w1/2, compute w for each peak and find the resolution between the two peaks.

Consider the peaks for heptane (14.56 min) and p-difluorobenzene (14.77 min) in the chromatogram. The column is 30.0 m long. (a) Measure w1/2 for each peak and calculate the number of plates and the plate height for each. (b) From w1/2, compute w for each peak and find the resolution between the two peaks.

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter26: An Introduction To Chromatographic Separations

Section: Chapter Questions

Problem 26.14QAP

See similar textbooks

Similar questions

A chromatogram from a certain column has a peak with a w1/ 2 of 12 mm and a tr of 650 mm as measured. What is the number of theoretical plates?
1a) Hexane, CH3(CH2)4CH3, is found to have a long retention time when separated from a mixture. A column with a C18 (18-carbon chain) stationary phase and a methanol-water modal phase is used for the separation. Explain why hexane has a long retention time. 1b)You wish to chromatographically seperate a mixtureof the follwing compunds. Which of the two compounds will be most difficult to seperatate from one another? Why?
To quantify the amount of ethanol in a beverage, a technician prepared the first solution which contained 4.90 grams unknown, 1.00 grams acetonitrile, and 4.10 grams water. After the GC analysis which reported the peak areas of 5,742 for ethanol and 3,829 for acetonitrile, the technician added 0.20 grams ethanol to the first solution and ran the GC analysis again. This time, the peak areas of 6,382 for ethanol and 3,709 for acetonitrile for solution 2 were obtained. What was the percent by mass ethanol in the original beverage?
3c. A solution containing 2.50 mM X (analyte) and 1.20 mM S (standard) gave peak areas of 2509 and 7132 respectively, in a chromatographic analysis. Then, 1.00 mL of 6.00 mM S was added to 5.00 mL of unknown X and the mixture was diluted to 10.0 mL. This solution gave peak areas of 4016 and 3138 for X and S, respectively. Calculate i. the response factor for the analyte ii. the concentration of S (mM) in the 10.0 mL of mixed solutioniii. the concentration of X (mM) in the 10.0 mL of mixed solutioniv. the concentration of X in the original unknown solution
explain what a response ratio is in Gas Chromatography and why it might be needed to quantify compounds in a mixture?
106.54 mg of an impure sample of the drug was diluted in 100 ml and injected in a HPLC, the AUC of the major peak in the chromatogram integrated 1140 units. A standard solution containing 1.13 mg/ml of this drug was then injected in the same HPLC and the resulting peak integrated 1912 units. What is the %w/w of purity for this sample?(One decimal place, no units)
Qno1: why there is a need of chromatography and chromatography thecniqs. B) when and where we should use normal and reverse phase chromatography
A method for the detection of morphine is used to generate a calibration curve in which the assay response (y) is plotted versus morphine concentration (x, in mg/L). This gives a straight line with a slope (m) of 0.241 and a y-intercept (b) of 0.011, where y = mx + b. The slope of this line has a standard deviation of ±0.007, and the standard deviation of the intercept is ±0.006. If the sample from an athlete gives a response of 0.506 ± 0.013 in this method, what is the concentration of morphine in the sample and estimated precision of this concentration?
Given below is a diagram of separation of two components of a mixture in a chromatographic column. From the diagram, which component has lesser affinity to the stationary phase? a X b Z c F d D
A spectrophotometric method for the quantitative determination of the concentration ofPb2+ in blood yields an Ssamp of 0.133 for a 1 mL sample of blood that has been diluted to 6 mL. A second sample is spiked with 1 µL of a 1467 ppb Pb2+ standard and diluted to 6 mL, yielding an Sspike of 0.491. Determine the concentration of Pb2+ in the original sample of blood.
In a chromatography experiment, a solution containing 0.083 7 M X and 0.066 6 M S gave peak areas of AX = 423 and AS 5 347. (Areas are measured in arbitrary units by the instrument.) To analyze the unknown, 10.0 mL of 0.146 M S were added to 10.0 mL of unknown, and the mixture was diluted to 25.0 mL in a volumetric flask. This mixture gave the chromatogram in Figure 5-8, with peak areas AX = 553 and AS = 582. Find the concentration of X in the unknown.
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.