Effects of Sodium Bicarbonate Concentration on Retention Time (SI-90 4E)

Please use this column with suppressor type ion chromatography system.

The concentration of sodium bicarbonate (NaHCO3) in eluent influences the retention of some anions when analyzed by IC SI-90 4E (a column for anions analysis). The relationship between sodium bicarbonate concentration and anions' retention time is shown below. Elution volumes of anions from fluoride to nitrate are not influenced considerably by the change in sodium bicarbonate concentration. While retention volumes of later eluting anions (phosphate and sulphate) are shorten by increasing the sodium bicarbonate concentration.


Sample : 20 μL
F- 2 mg/L
Cl- 3 mg/L
NO2- 5 mg/L
Br- 10 mg/L
NO3- 10 mg/L
HPO42- 15 mg/L
SO42- 15 mg/L
I- 10 mg/L


Column       : Shodex IC SI-90 4E (4.0 mm I.D. x 250 mm)
Eluent       : 1.8 mM Na2CO3 + NaHCO3 aq.
Flow rate : 1.0mL/min 
Detector : Suppressed conductivity 
Column temp. : 25 °C

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