According to Japanese Testing Methods for Fertilizers (2019*), "6.2.a Ion chromatography method" under "6.2 Chloride" includes both suppressor and non-suppressor methods. The non-suppressor method should be carried out with a column filled with hydrophilic polymethacrylate gel modified with quaternary ammonium groups. The method mentions that this analysis is applicable to potassium sulfate, potassium bicarbonate, magnesium-containing potassium sulfate, fish meal powder, fish meal, and compost, and IC NI-424 as a suitable column. In this application, a standard solution and one target fertilizer, potassium sulfate, were analyzed using NI-424. The calibration curve for chloride ion showed high linearity with a coefficient of determination (R² = 0.9998) over the concentration range of 1 to 100 µg/mL.
Analysis of chloride in fertilizers by a suppressor method is also available here.

Sample Preparation according to "(4.1) Extraction"

1. (1)Weigh 1.00 g of the test material and place it in a 200 mL screw-capped Erlenmeyer flask.
2. (2)Add 100 mL of water and stir for 10 minutes on a shaker.
3. (3)After standing, transfer the supernatant into a 50 mL screw-capped centrifuge tube and centrifuge at 1700 x g for about 5 minutes.
4. (4)Dilute the supernatant precisely 20-fold with water.
5. (5)Filter through a 0.45-µm membrane filter and use it as a sample.

*The version at the time of the application acquisition.

Sample: 20 µL each
(Standard solution) 5 mg/L of Cl^-

1. 1.Cl^-

(Sample solution)

1. 1.Cl^-

 

1.