Anions

 

1.  Materials:

1.  Dionex chromatographer

2.  stock solutions for Cl^-1 and SO₄²

3.  7 100-ml volumetric flasks

4.  Nanopure water

5.  100- and 1000-l pipettes (calibrated), tips

6.  7 125 ml poly bottles to store standards

 

2.  If Total Anion concentration is < 600 um the Dionex can be set up to run on the Fast column (~ 3 min / sample).  Make sure that the Dionex has plenty of regenerant and eluent.

 

Regenerant (2 liters)

 

100 ml .5 N H₂SO₄ (27.7 ml H₂SO₄ in 2 liter DI)

Fill to 2 Liters with DI

 

Eluent (2 liters)  Should be relatively fresh.

 

.4240g Na₂CO₃ and

0.0252 g NaHCO₃

Fill to 2 liters

 

3.  Standard stock solutions for cloride and sulfate can be made in the same volumetric

 

Cloride = Sodium Cloride NaCl (FW = 58.44)

10 mM NaCl = .05844 g / 100 ml

 

Sulfate = Sodium Sulfate Na₂SO₄ (FW = 142.04)

10 mM Na₂SO₄ = .142. g / 100ml

 

4.  Standards:

1.  2 uM Cloride & sulfate = 20 ul 10 mM NaCl & 20 ul 10 mM Na₂SO₄ /100 ml DI

2.  5 uM Cloride & sulfate = 50 ul 10 mM NaCl & 50 ul 10 mM Na₂SO₄ /100 ml DI

3.  10 uM Cloride & sulfate = 100 ul 10 mM NaCl & 100 ul 10 mM Na₂SO₄ /100 ml DI

4.  15 uM Cloride & sulfate = 150 ul 10 mM NaCl & 150 ul 10 mM Na₂SO₄ /100 ml DI

5.  30 uM Cloride & sulfate = 300 ul 10 mM NaCl & 300 ul 10 mM Na₂SO₄ /100 ml DI

 

5.  The attenuation will need to be changed for the different concentrations in the standard curve.  On the fast column the following work well.  For actual area under the curve multiply the attenuation by the area.

 

Standard	concentration (uM)	attenuation
1	2	1
2	5	1
3	10	3
4	15	3
5	30	10

 

6.  To run a sample:

1.  Inject sample into port (>1 ml)

2.  Hit [Load/ Inject] (valve will switch)

3.  Change attenuation if needed

4.  Plot sample [Shift/Down] [Plot] [Enter]