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  1. Use equation 25-1to estimate the length of a column required to achieve1.0104plates 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?

Short Answer

Expert verified

For the part(a), the length of the columns areL=33cm,17cm,10cm,and5cm respectively.

For the part(b),tr=10min,6min,and3min respectively.

For the part (c), the pressurep=18MPa,49MPa,196MPa respectively.

For the part (d), the baseline width is

w=0.8,1.6mL;w=0.24min,0.48mL;w=o.12min,0.2mLrespectively.

For the part (e),1.5渭尘 particle would require a UHPLC instrument.

Step by step solution

01

Calculating the column length of the stationary phase particles.

The equation 25-1gives us the below,

N=3000Ldp

We have express as below,

L=Ndp3000

When the stationary phase particle size is10.0渭尘 , the length of the column is,

role="math" localid="1655028224449" L=1104103000L=33cm

When the stationary phase particle size is5.0渭尘 , the length of the column is,

L=110453000L=17cm

When the stationary phase particle size is3.0渭尘 , the length of the column is,

L=110433000L=10cm

When the stationary phase particle size is1.5渭尘 , the length of the column is,

L=11041.53000L=5cm

02

Calculating the retention time of the stationary phase particles.

Since the flow rate is constant for all columns, the retention time decreases proportionally with the size of the particle.

The given is10.0渭尘particle has the retention time of20 mins. So the 5.0渭尘particle has50% less retention time.

tr=20min0.5=10min

The3.0渭尘 particle would have 70%less retention time 30%

tr=20min1.5=3min

The 1.5渭尘particle would have 85%less retention time 15%

tr=20min0.15=3min

03

Calculating the pressure of the stationary phase particles.

The equation 25-2gives us the below equation,

p=fuvLr2dp2

From the above formula, we can know that the pressure is inversely proportional to the square of the size of the particle.

The given is, for the10.0渭尘particle(d1)has the pressure4.4MPa(p1)

So the particle 5.0渭尘(d2)will have the pressure p2.

role="math" localid="1655029638610" p1p2=d22d12p2=p1d12d22p2=(10渭尘)24.4MPa(5渭尘)2p2=18MPa

04

Calculating the pressure of the stationary phase particles.

So the particle 3.0渭尘(d2)will have the pressure p2.

p1p2=d22d12p2=p1d12d22p2=(10渭尘)24.4MPa(3渭尘)2p2=49MPa

So the particle 1.5渭尘(d2)will have the pressure p2.

p1p2=d22d12p2=p1d12d22p2=(10渭尘)24.4MPa(1.5渭尘)2p2=196MPa

05

Calculating the baseline width in time unit and volume unit of the particles.

The baseline width can be calculated by using the below formula,

N=16tr22

The baseline width in time unit is,

=1N4tr

To calculate the baseline width in volume unit, we need to multiply with flow rate.

For a10.0渭尘 particle, the baseline width in time unit is,

role="math" localid="1655030126576" =11104420min=0.8min

The same baseline width in volume unit is,

role="math" localid="1655030532545" =0.8min2mL/min=0.16mL

For a5.0渭尘 particle, the baseline width in time unit is,

=11104410min=0.4min

The same baseline width in volume unit is,

=0.4min2mL/min=0.8mL

For a3.0渭尘 particle, the baseline width in time unit is,

=1110446min=0.24min

The same baseline width in volume unit is,

=0.24min2mL/min=0.48mL

For a1.5渭尘 particle, the baseline width in time unit is,

=1110443min=0.12min

The same baseline width in volume unit is,

=0.12min2mL/min=0.24mL

06

Identifying the size of the particle that requires the UHPLC instrument.

For the part(e),1.5渭尘 particle would require UHPLC instrument.

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