Page 39 - Application Handbook - Liquid Chromatography

LAAN-J-LC-E106

LC
Liquid Chromatograph
Analysis of Dicyandiamide in

33 Fertilizers

The dicyandiamide contained in calcium cyanamide is used as a type of nitrification suppressant to inhibit ammonia from changing
into nitric acid. In accordance with the partial revision to the matters specifying official standards for general fertilizers based on
the Fertilizers Regulation Act (The Ministry of Agriculture, Forestry and Fisheries of Japan; Notification No. 1985; dated August 8,
2012), the content of dicyandiamide-nitrogen in calcium cyanamide is to be 20.0 % or less of the total nitrogen content.
This article introduces an example of the analysis of dicyandiamide in fertilizer, with reference to the fertilizer test method (2012)
under the supervision of the Japan‘s Food and Agricultural Materials Inspection Center (FAMIC).
(A. Uchida, T. Yamaguchi)
 Analysis of Standard Solution
Fig. 1 shows the results of the analysis of a standard solution of dicyandiamide (10 mg/L, dissolved in methanol) using an amino
column. The analytical conditions are shown in Table 1.

Table 1: Analytical Conditions
mAU
40
1  Peak Instrument: Prominence HPLC system
1. Dicyandiamide Column: Unison UK-Amino (Imtakt Corp.,
30 150 mmL. × 4.6 mmI.D., 3 µm)
Mobile phase: Acetonitrile / Methanol = 6/1 (v/v)
Flow rate: 1.0 mL/min
Column temp.: 40 °C
20 Detection: SPD-20AV at 214 nm
Injection volume: 5 µL
10

0
0.0 2.5 5.0 7.5 min
Fig. 1: Chromatogram of Dicyandiamide

 Linearity and Repeatability
2
Fig. 2 shows the calibration curve for dicyandiamide in the range of 1 mg/L to 50 mg/L. The contribution ratio (R ) was 0.999 or
higher, indicating that favorable linearity was obtained. Calculating the detection limit and quantitation limit based on the absolute
calibration curve for dicyandiamide in Fig. 2 yields 0.15 mg/L and 0.46 mg/L, respectively. Table 2 shows the relative standard
deviation (n=6) for the peak area for each component when the dicyandiamide standard solution (1 mg/L) was analyzed.
Favorable results were obtained, with a relative standard deviation of 0.48 %.

Table 2: Repeatability
Area
面積
2000000
Standard solution
1750000 1 mg/L
1500000
1st 41511
1250000
2nd 41543
1000000
3rd 41107
750000
Contribution ratio
2
500000 (R ) = 0.9996 4th 41561
5th 41143
250000
6th 41482
0
0 10 20 30 40 Conc.
濃度
Fig. 2: Linearity (1 to 50 mg/L) %RSD 0.479