Collection of three absorbance peaks

Introduction

This section contains an example of how to collect three absorbance peaks through outlets F3, F5 and F7 with waste fractions through outlets F4, F6 and F8.

The maximum number of peaks collected in this example is three due to the limited number of positions on the outlet valve.

Recommendations

Waste container needed

The waste fractions between the peaks are collected through the outlet valve positions F4, F6 and F8, so ensure that the tubing from these positions is lead to a suitably large container.

Condition for UV threshold

The UV threshold for collecting the waste fraction must be below the threshold for collecting the peak fraction so that the “waste” condition will not be fulfilled simultaneously or immediately after peak collection.

Example instruction

This is an example instruction as it would be presented in the Text window:

0.00 Block Eluate_Fractionation

(Eluate_Fractionation)

0.00 Base SameAsMain

0.00 Watch_UV1 Greater_Than, 5 {mAU}, Peak

(Peak)

0.00 Base SameAsMain

0.00 OutletValve Feed

0.00 Watch_UV1 Less_Than_Or_Valley, 4.75 {mAU}, Waste

(Waste)

0.00 Base SameAsMain

0.00 OutletValve Feed

0.00 Watch_UV1 Greater_Than, 5 {mAU}, Peak1

(Peak1)

0.00 Base SameAsMain

0.00 OutletValve Feed

0.00 Watch_UV1 Less_Than_Or_Valley, 4.75 {mAU}, waste1

(Waste1)

0.00 Base SameAsMain

0.00 OutletValve Feed

0.00 Watch_UV1 Greater_Than, 5 {mAU}, Peak2

(Peak2)

0.00 Base SameAsMain

0.00 OutletValve Feed

0.00 Watch_UV1 Less_Than_Or_Valley, 4.75 {mAU}, Waste2

(Waste2)

0.00 Base SameAsMain

0.00 OutletValve WasteF1

0.00 End_block

0.00 End_block

0.00 End_block

0.00 End_block

0.00 End_block

0.00 End_block

0.00 End_block
This is what happens

The table below describes what happens in the above example:

Stage

Description

1

When the UV reaches 5 mAU or more, the outlet valve is switched to the position for collecting the first peak.

2

When the UV reading goes down to 4.75 mAU, the outlet valve switches to the next position to separate the waste fraction from the collected peak fraction.

3

This process is repeated twice for the next two peaks so that when the UV reading rises above 5 mAU, the position switches to collect the peak fraction and the position switches again to collect the waste fraction when the UV reading falls again.

2005-06-15