The Japanese regulation for “Testing Methods for Fertilizers (2019*)” lists IC NI-424 as a non-suppressor type IC (anion) column for the analysis of chloride in fertilizers. This method applies to fertilizers, such as “potassium sulfate”, “potassium bicarbonate”, “magnesium potassium sulfate”, “fish powder”, “fish meal”, and “compost”.
In this application, we used NI-424 to analyze chloride standard solution and potassium sulfate, one of the fertilizers included in the method. A good linearity was obtained for the calibration curve in the concentration range 1 to 20 μg/mL chloride.
Analysis of chloride in fertilizer using a suppressor method is also available here.

*The version at the time of the application acquisition.

Sample preparation
1. Weigh 1.00-g of the target sample and put it in a 200-mL Erlenmeyer flask with stopper.
2. Add 100-mL water and mix the contents for 10 minutes by placing the flask on a flask shaker.
3. Pour the supernatant into a 50-mL centrifuge tube with stopper and centrifuge at 1,700 x g for about 5 minutes.
4. Dilute the supernatant 1 + 19 fold with water.
5. Filter the mixture with a 0.45-µm membrane filter and use it as a sample.

Sample : 20 μL
Srandard 5 mg/L
Extracted sample
1. Cl^-

Columns      : Shodex IC NI-G (4.6 mm I.D. 10 mm) + NI-424 (4.6 mm I.D. x 100 mm)
Eluent       : 2.1 mM Phthalic acid + 2.9 mM Amino-n-capronic acid
               + 6 mM Phenylboronic acid aq.
Flow rate    : 1.0 mL/min
Detector     : Non-suppressed conductivity
Column temp. : 40 °C