Waters IC-Pak C Method Development Column - Manual (Page 5)

[ Care and Use ManUal ]
Waters IC-Pak C M/D Column 5
To prepare 1 liter of working standard:
1. Measure the appropriate quantity of stock standard (refer to Table 2).
2. Add the stock standard to a plastic 1000 ml volumetric flask.
3. Fill the flask to the mark with 18 megohm water. Table 2 shows
the concentrations for the monovalent and divalent cation working
standards.
4. Store working standards in clean plasticware at room temperature for
up to one month.
Table 2: Working Standard Solutions and Final Concentrations
Determining Column Efficiency
Use a flow rate of 1.0 ml/min. The peak for potassium should yield
>2,000 plates by the half-height method on a low dispersion Waters
ion chromatograph.
Figure 2 shows the conditions and resulting chromatogram for
monovalent and divalent cation standards.
Figure 2: IC-Pak C M/D Standard Cation Chromatogram
Calculating Efficiency
Use the potassium peak (#4) to measure your column efficiency
with the half-height method equation in Figure 3.
Figure 3: Half-Height Method Test Calculations
V. CAre & MAIntenAnCe
a. Storing the Column
For short-term storage, leave the mobile phase in the column with
the column connected to the system.
If the column will not be used for more than 72 hours, store it in
20/80 acetonitrile/water (v/v).
When storing columns:
DO NOT store the column in methanol or methanol-containing
solutions. Over time, methanol causes significant decreases in
cation retention times. To prevent growth of bacteria, fill with 20/80
acetonitrile/water (v/v), replace the end plugs, and return the column
to its box.
DO NOT allow the column to dry out. Allowing the column packing to
dry out can result in poor chromatographic performance.
Store at 15 °C to 35 °C. Freezing during storage degrades
performance.
Cation Use This Volume of
Stock Standard To Yield This Concentration of
Working Standard (ppm)
Li + (Lithium) 0.250 ml 0.25
Na + (Sodium) 1.000 ml 1.00
NH4 + Ammonium) 1.000 ml 1.00
K + (Potassium) 3.000 ml 3.00
Mg
2
+ agnesium) 2.000 ml 2.00
Ca
2
+ (Calcium 3.000 ml 3.00
Sr
2
+ (Strontium 5.000 ml 5.00
Ba + (Barium) 5.000 ml 5.00
T
R
Injec
t
W1/2
1/2h
h
Column efficiency (plates)
Time to peak apex (minutes)
Width of peak at 1/2 peak height (minutes)
N = 5.54 x
2
Time (minutes)
0 5 10 15 20 25
15.0 µS
1
2 3
4
5
6
7
8
1. Lithium
2. Sodium
3. Ammonium
4. Potassium 0.25 ppm
1.0 ppm
1.0 ppm
3.0 ppm
5. Magnesium
6. Calcium
7. Strontium
8. Barium 2.0 ppm
3.0 ppm
5.0 ppm
5.0 ppm
Conditions
Column IC-Pak C M/D
Eluent 0.1 mM EDTA/
3 mM HNO3
Detector Waters 431
Conductivity
Flow Rate 1.0 mL/min
Injection
Volume 100 µL