Your lab uses a UHPLC method for quantifying the active ingredient of Tylenol. The method is based on a C18 column (2.1 x 50 mm, 1.7 um). Elution was isocratic using 30% aqueous acetonitrile containing 0.01% formic acid. Flow rate was 0.6 ml/min. Acetaminophen elutes with a retention time of 0.53 min and a width at half height of 1.3 s. a) How many plates has your column? b) How many 1.7 um diameter particles placed side-by-side are equal to one theoretical plate?

Your lab uses a UHPLC method for quantifying the active ingredient of Tylenol. The method is based on a C18 column (2.1 x 50 mm, 1.7 um). Elution was isocratic using 30% aqueous acetonitrile containing 0.01% formic acid. Flow rate was 0.6 ml/min. Acetaminophen elutes with a retention time of 0.53 min and a width at half height of 1.3 s. a) How many plates has your column? b) How many 1.7 um diameter particles placed side-by-side are equal to one theoretical plate?

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

Chapter27: Gas Chromatography

Section: Chapter Questions

Problem 27.19QAP

See similar textbooks

Similar questions

▪ In a blood alcohol analysis by GC-FID, methanol elutes at 1 min, ethanol at 2 min, IPA at 3 min, and IS at 4 min. In the patient sample, the analyte elutes t 2 min and the IS at 8 min. What is the relative retention time and the analyte in the patient? A) methanol B) Ethanol chu C) IPA
Polar compounds were separated by HPLC using a bonded phase containing polar diol substituent [-CH(OH)CH2OH]. How would the retention times be affected if the eluent were changed from 70 vol.% to 30 vol.% of acetonitrile in water? O Retention times will be unchanged. Retention times will be shorter KO Retention times will be longer O Changes in retention times are not sure.
An unretained solute is eluted from a GC column in 1.80 min. Decane (C10H22) is eluted in 15.63 min and undecan (C11H24) is eluted in 17.22 min. What is the retention time (report to 2 decimal places, in minutes) of a compound whose retention index is 1050?
A solute has a retention time of 5.4 min with a width at half height of 0.41 min on a column 12.2 m long. Find the number of plates. Please round-off your answer to a whole number (no decimal place)
From the data calculate: a) retention factor of each solute b) selectivity factor c) how many plates are needed to provide a resolution of 1.5? d)how long a column is needed if the plate height of the packing is 1.5x10^-3cm? e)if the flow rate is 6.75 cm/min how long will it take to elite the two species?
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
A student developed a new dye called Dye C. It was analyzed against other dyes using paper chromatography. A solution of 1:1 ethyl acetate:hexane was used as the eluent. The resulting chromatogram is shown in the figure. Determine the retention factor (Rf) values of each spot on dye C. (use 2 decimal places) What other dye/s are present in dye C and what is the dye with least number of pigments?
anch of the following components cannot be detected by gas chromatography? 4 Essential oils Alcohols b) Volatile compounds d) Non-volatile compounds 13- is measured as time elapsed from the point of injection to the peak maximum? a)-Column efficiency d)- Delectability c)-Retention time 14- Which of the following can be used to detect the components in gas chromatography a) non-volatile compounds b) volatile compounds c) Salts d) b&c 15-Which of the following methods is often referred to as mechanical separation processes. a)-Gas Chromatography b)-column chromatography c)- Sedimentation 16- For obtaining better resolution in TLC. and then developed with a second solvent at right angles to the first a) Stepwise b) Descending e) Ascending 17- This is defined as transport of electrically charged particles in a direct-current electric field a) ion exchange chromatography b) Electrophoresis c) ultracentrifuge d) exclusion 18-This figure indicates to schematic Diagram of a) Gas chromatography…
An unknown compound was analyzed by GC with octane (C3H18) and decane (C10H22). The adjusted retention times were 14.6 min for octane, and 31.6 min for decane. Calculate the retention index for the unknown if its adjusted retention time was 21.2 min.
In a reverse-phase separation, a solute was found to have a retention time of 19.6 min, while an unretained peak had a retention time of 1.45 min when the mobile phase was 20/80 v/v% methanol/water. (b) Calculate the k’ for the solute. (c) Calculate the new k’ if the mobile phase is changed to 60/40 methanol/water assuming identical void volume. (d) Calculate a solvent composition that would bring k’ from initial value to a value of 1.20 using tetrahydrofuran/water mobile phase rather than 20/80 v/v % methanol/water.
A student researcher performed a chromatographic separation of caffeine and aspartame. The retention time for caffeine, tc, was found to be 209.6 s with a baseline peak width, w., of 14.4 s. The retention time for aspartame, ta, was 260.0 s with a baseline peak width, wa, of 21.2 s. The retention time for the unretained solvent methanol was 49.2 s. Calculate the average plate height, H, in micrometers for this separation, given that it was performed on a 22.1 cm long column. H = um %3D Calculate the resolution, R, for this separation using the widths of the peaks. R = Calculate the resolution if the number of theoretical plates were to increase by a factor of 2. R2N =
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?