IonPacAS9-SC
034656-06
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solvents will usually ensure that your chromatography is not affected by ionic impurities in the solvent. Currently at DIONEX, we
have obtained consistent results using High Purity Solvents manufactured by Burdick and Jackson and OPTIMA® Solvents by
Fisher Scientific.
4.3.3 Deionized Water
The deionized water used to prepare eluents should be Type I Reagent Grade Water with a specific resistance of 18.2 megohm-
cm. The deionized water should be free of ionized impurities, organics, microorganisms and particulate matter larger than 0.2 µm.
Bottled HPLC-Grade Water (with the exception of Burdick & Jackson) should not be used since most bottled water contains an
unacceptable level of ionic impurities.
4.4
Eluent Preparation
NOTE
Always degas and store all eluents in glass or plastic eluent bottles pressurized with helium. Only helium can be
used to purge and degas ionic eluents containing solvents, since nitrogen is soluble in solvent containing eluents.
The above precautions, if taken when making eluents, ensure smooth, reproducible ramps, with minimum total change in
background conductivity when using sodium carbonate/bicarbonate (isocratic) or borate (isocratic and gradient) eluents with the
AS9-SC columns.
The following table details the use of the above eluent types:
Table 5
Eluent Type Selection
Eluent
Application
Bicarbonate/Carbonate
Isocratic Analysis
Borate
Isocratic or Gradient Analysis
Hydroxide
DO NOT USE!
4.4.1 Preparation of Carbonate Eluent Concentrates
A.
0.5 M Sodium Carbonate (Na
2
CO
3
) Concentrate
1.
Order DIONEX P/N 037162
or
2.
Thoroughly dissolve 26.49 g of Na
2
CO
3
in 400 mL of deionized water with a specific resistance of 18.2 megohm-
cm. Dilute to a final volume of 500 mL.
B.
0.5 M Sodium Bicarbonate (NaHCO
3
) Concentrate
1.
Order DIONEX P/N 037163
or
2.
Thoroughly dissolve 21.00 g of NaHCO
3
in 400 mL of deionized water with a specific resistance of 18.2 megohm-
cm. Dilute to a final volume of 500 mL.
C.
200 mM Na
2
CO
3
/75 mM NaHCO
3
(100X)
The standard test eluent can be readily prepared from this 100X concentrate. This
eluent concentrate can be
prepared by thoroughly dissolving 21.978 g of sodium carbonate (MW 106.00 g/mole) plus 6.301 g sodium
bicarbonate (MW 84.00 g/mole) in 700 mL of degassed, deionized water with a specific resistance of 18.2
megohm-cm in a 1 L volumetric flask. Dilute to a final volume of 1,000 mL. This solution can be diluted to make
