Waters Dextro-Pak Cartridge - Manual (Page 5)

[ Care and Use ManUal ]
Dextro-Pak Cartridge 5
a. Cartridge Test Procedure
1. Install cartridge and condition it according to the startup
procedure.
2. Make up a standard solution using:
25 mg glucose
45 mg maltose
80 mg maltotriose
160 mg ethanol
3. Weigh out 160 mg of ethanol in a capped sample vial, then add
4 mL water.
4. Weight out the sugars and dissolve in the water/ethanol.
Note: Accuracy for this test need only be ± 5% unless this mixture
is being used as a quantitation standard. Use this mixture the
same day as prepared to avoid microbial degradation.
5. Use water as the mobile phase at 1 mL/min, Model 410
Refractive Index Detector at 64x, sensitivity 20. Inject 10
to 40 µL.
6. If you do not obtain a chromatogram similar to that shown in the
figure below repeat steps 1 through 3.
vI. Column effICIenCy
Waters measures cartridge efficiency by using the 5 sigma plate
count method. This is determined by measuring the peak width
at 4.4% of the peak height. Unlike half-peak height and tangent
methods used by other manufacturers, this stringent method takes
into consideration peak asymmetry.
Confirm the efficiency of the Dextro-Pak cartridge by performing the
test below.
1. Inject a 2% w/V solution of sucrose at a flow rate of 1 ml/min
and a chart speed of 10 cm/min.
2. Record the plate count efficiency of new cartridges before they
are used.
3. Track subsequent loss of efficiency by repeating this test.
Note: Lack of required efficiency is not always dependent on the condi-
tion of the cartridge. It also depends on the condition of the liquid
chromatographic system.
Contact our Waters representative for details on how to test or
band broadening caused by the LC system. Retain the results as a
performance test.
vIII. Cart rIdge lIfe
Liquid chromatography cartridges have a finite life influenced by
such factors as their care and use, number of injections, sample an
solvent cleanliness, frequency of solvent changeover and handling
and storage procedures. If a change is observed in the retention of
a particular compound, resolution between two compounds, or peak
shape, tae immediate steps to determine the reason for the change.
Until you have made this determination, you must not rely upon the
results of any separation using the cartridge.
Important Note: Before running the first analysis on your new
cartridge, perform the test sample separation given in the test
conditions section.
K =
V n - V 0
V 0
N 25 =
( )
2 V
R
W