/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q8P 聽a) UHPLC can provide exquisite... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 25: Q8P (page 707)

a) UHPLC can provide exquisite resolution when run slowly on long columns or rapid separation with reasonaple resolution if short columns are run fast. the drug acetaminophern run on a 50脳2.1mmc18UHPLC column has a retention time of 0.63min and a width at half-height of 2.3s.Find the plate number and plate height. How many1.7渭尘 diameter particles places placed dide-by are equal to one theoretical plate?

b) From figure25-3,we expect an optimum plate height of 4渭尘 how many particles placed side-by- side are equal to one theroretical plate? Do you think the column in (a) is being run for maximum resolution or maximum speed?

Short Answer

Expert verified

UHPLC can provide exquisite resolution when run slowly on long columns.

how many particles placed side-by- side are equal to one theoretical plate.

N=5.55.(37.8s)2(2.3)2N=1500

4渭尘1.7渭尘=2.4

(a)N=1500;H=33渭尘;19.4particle/plate

b) 2.4particle/plate

Step by step solution

01

definition of plate calculated using the formula

a) The number of plates on column can be calculated using the formula

N=5.552.trw21/2

N=5.55.(37.8s)2(2.3)2N=1500

The plate height is:

H=LNH=50mm1500H=0.033mm=33渭尘

The number of particles that are equal to one theoretical plate is

33渭尘1.7渭尘=19.4particle/plate

02

theoretical plate

The number of particles that are placed side-by-side and equal to one theoretical plate is:

4渭尘1.7渭尘=2.4particle/plate

The column in task (a) is being run for maximum speed because it has higher plate height and number of particles. b

Hence,

(a)N=1500;H=33渭尘;19.4particle/plate

b) 2.4particle/plate

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

  1. Use equation 25-1to estimate the length of a column required to achieve1.0脳104plates if the stationary phase particles size is10.5,5.0,3.0,or1.5渭尘

  2. If the retention time was 20mins on the 10.0渭尘 particle size column, what is the retention time on the 5.0,3.0,or1.5渭尘columns from part (a)? Assume that flow rate is constant for all columns.

  3. Use equation25-2to estimate the pressure of the column in (a) given that the pressure of the10.0渭尘column was4.4Mpa

  4. If the flow rate was2.0mL/min , what is the baseline width for the peaks on 10.5,5.0,3.0,or1.5渭尘columns form part (a)?

  5. Which of these column configurations would require a UHPLC instrument?

HPLC peak should generally not have an asymmetry factor, B/A in figure 23-14,outside the range0.9-1.5

  1. Sketch the shape of a peak with an asymmetry of 1.8
  2. What might you do to correct the asymmetry?

(a) Nonpolar aromatic compounds were separated by HPLC on an octadecyl(C18)bonded phase. The eluent was 65 vol% methanol in water. How would the retention times be affected if 90% methanol were used instead?

(b) Octanoic acid and 1-aminooctane were passed through the same column described in (a), using an eluent of 20% methanol/80% buffer (pH 3.0). State which compound is expected to be eluted first and why.

role="math" localid="1656416023291" CH3CH2CH2CH2CH2CH2CH2CO2HOctanoicacidCH3CH2CH2CH2CH2CH2CH2CH2NH21鈥�Aminooctane

(c) Polar solutes were separated by hydrophilic interaction chromatography (HILIC) with a strongly polar bonded phase. How would retention times be affected if eluent were changed from 80 vol% to 90 vol% acetonitrile in water?

(d) Polar solutes were separated by normal-phase chromatographyon bare silica using methyl t-butyl ether and 2-propanol solvent. How would retention times be affected if eluent were changed from 40 vol% to 60 vol% 2-propanol? (Hint: See Table 25-4.)

Retention factors for three solutes separated on aC8non-polar stationary phase are listed in the table. Eluent was a 70 : 30 (vol/vol) mixture of 50 mM citrate buffer (adjusted to pH withNH3) plus methanol. Draw the dominant species of each compound at each pH in the table and explain the behavior of the retention factors.

The 鈥渞ule of three鈥� states that the retention factor for a given solute decreases approximately threefold when the organic phase increases by10%.In figure 25-12,tm=2.7min. Find k for peak 5at 40%B .predict the retention time for peak at B and compare the observed and predicted times.
See all solutions

Recommended explanations on Chemistry Textbooks

Ionic and Molecular Compounds

Read Explanation

Chemical Analysis

Read Explanation

Chemical Reactions

Read Explanation

Nuclear Chemistry

Read Explanation

Chemistry Branches

Read Explanation

Inorganic Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.