Anion Analysis using Ion Chromatography with Chemical Suppression

By Masao Bounashita

Download PDF October 7, 2021

  • Industry

  • Technique

Introduction

ICSpak is a suppressor technology for anion exchange chromatography developed by JASCO. The packing material has a sulfonic acid group chemically bonded to a styrene-divinylbenzene porous polymer and packed in a PEEK column. The suppressor is used in anion chromatography to decrease the background signal from the eluent and to change the sample to an ion-pair with high equivalent conductivity. This suppressor can be re-cycled using regeneration and washing steps. The more sensitive detection of nitrate and nitrite ions is made using a UV detector.

This report describes the analysis of anions using an inert anion exchange chromatography system with ICSpak suppressor.

Experimental

EquipmentConditions  
Pump:PU-4080iColumn:Shodex IC SI-90 4E (4.6mmI.D. x 250mmL)
Pump Option:DG unitSuppressor:ICSpak (4.6mmI.D. x 100mmL)
Autosampler:AS-4050iEluent:1.8mM Na2CO3 + 1.7mM NaHCO3
Column Oven:CO-4060Flow rate:1.0mL/min
Detector:UV-4075 (Inert Cell)Column temp.:25ºC
 Shodex CD-5Wave length:215nm
  Injection volume:100 μL
  Standard Sample:Anion Mixture (Described below)
AnionsConc. [mg/L]
F-0.2
Cl-0.3
NO2-0.5
Br -1
NO3-1
PO43-1.5
SO42-1.5
flow path diagram of anion chromatography
Fig.1 The flow path diagram

Keywords

Anion Exchange Chromatography, Chemical Suppression, HPLC, conductivity detector, ion suppression.

Results

Fig.2 Chromatograms of anion standard solution mixture. 7-component anions.

Chromatograms of anion standard solution mixture using Shodex IC SI-90 4E and chemical suppressor ICSpak Top: UV detector, Bottom: Conductivity detector 1: F-, 2: Cl-, 3: NO2-, 4: Br-, 5: NO3-, 6: PO43-, SO42-
Figure 2. Chromatograms of anion standard solution mixture using Shodex IC SI-90 4E and chemical suppressor ICSpak Top: UV detector, Bottom: Conductivity detector 1: F-, 2: Cl-, 3: NO2-, 4: Br-, 5: NO3-, 6: PO43-, SO42-
Table 2 Detection limit for a range of anions.

The CO-4065 can be fitted with two optional valves. Analysis and regenerating/washing can be performed in parallel using the CO-4065 with two 2-position/6-port switching valves and two ICSpak suppressor columns with a multi-solvent regenerating/washing pump (e.g., the PU-4180 fitted with a low pressure gradient unit) as shown in the fig.3.

Equipment 
Pump:PU-4180
Pump Option:DG unit
 LPG unit
R-Pump Unit:R-PU-4080i
Autosampler:AS-4050i
Column Oven:CO-4065
Oven Option:2 way 6 port x 2
Detector:UV-4075 (Inert Cell)
 Shodex CD-5
Flow path of a system for parallel analysis and regenerating/washing
Figure 3 Flow path of a system for parallel analysis and regenerating/washing

System on page 1

System on page 2

Anion Analysis using Ion Chromatography with Chemical Suppression

About the Author

Masao Bounashita