52 February / March 2019 Results
The chromatogram of the standard mixture containing melamine and its related substances (1 mg/L each) is shown in Figure 3. The range of calibration curves are from 0.05 up to 5 mg/L for each compound. The results show good linearity, with R2 ≥ 0.9999. The relative standard deviation (% RSD) for each peak area from six consecutive analyses was 0.41% for cyanuric acid, 0.42% for ammelide, 0.52% for melamine and 0.56% for ammeline respectively.
Figure 2: Sample pre-treatment procedure.
Five different kinds of fertilisers were analysed as displayed in Figure 4. Quantities of target compounds obtained in the evaluated samples were approximately 0.035 to 2.8%w/w melamine, 0.035 to 1.6%w/w ammeline, 0.035 to 1.1%w/w ammelide and 0.037 to 1.2%w/w cyanuric acid respectively.
Conclusion
A robust, fast and sensitive HPLC method has been developed for the determination of melamine and its related substances in fertilisers. The results demonstrate that the proposed assay can satisfy the provisional 0.4%w/w melamine limit issued by the Food Safety and Consumer Affairs Bureau, Ministry of Agriculture (Japan), Forestry and Fisheries for calcium cyanamide and fertilisers that contain calcium cyanamide as a component.
Acknowledgements Figure 3: Chromatogram of standard mixture of melamine and related substances (each 1 mg/L).
This study was carried out as a collaborative study supported by the Food and Agricultural Materials Inspection Center (FAMIC) in Japan. We would like to give special thanks to all of the members at the Fertilizer and Feed Inspection Department in FAMIC.
References
1.
https://www.cdc.gov/niosh/ipcsneng/neng1154.html (Nov. 2018)
2. Food Safety Commission of Japan, October 9, 2008, updated April 30, 2009
3. Food Safety and Consumer Affairs Bureau, Ministry of Agriculture, Forestry and Fisheries in Japan, Notice No. 6116, 2012, issued March 25, 2013 and partially revised March 30, 2013
Figure 4: Chromatograms for (A) Nitrolime 1, (B) Nitrolime 2, (C) Synthetic fertiliser containing calcium cyanamide, (D) Synthetic fertiliser and (E) Ammonium sulphate.
4. Testing Methods for Fertilizers (2016), Food and Agricultural Materials Inspection Center (FAMIC):
http://www.famic.go.jp/ffis/fert/obj/ TestingMethodsForFertilizers2016.pdf (Nov. 2018)
milligram fertiliser samples were weighed into an Erlenmeyer flask and extracted in an ultrasonic bath for 30 min, using a mixture of hydrochloric acid / water (1:15 v/v). The samples were then centrifuged at 2000 x g for 5 min, and 5 ml of the supernatant were transferred into a 50 ml volumetric flask and diluted to
volume with a mixture of acetonitrile/ phosphate buffer (4:1 v/v). Aliquots of the dilute sample were again centrifuged at 8000 x g for 5 min, and the supernatant was transferred to an HPLC vial for analysis. The sample pretreatment procedure is illustrated in Figure 2 [5-6].
5. Etsuko Bando and Yuji Shirai: Validation of High Performance Liquid Chromatography (HPLC) for Determination of Melamine and Its Related Substances in Fertilizer, Research Report of Fertilizer Vol. 6, pp. 27 - 35 (2013)
6. Etsuko Bando and Shigehiro Kai: Determination of Melamine and Its Related Substances in Fertilizer by High Performance Liquid Chromatography (HPLC): A Collaborative Study, Research Report of Fertilizer Vol. 7 pp. 10 - 21 (2014)
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
