VALIDASI METODE KJELDAHL TANPA ASAM SALISILAT DALAM ANALISIS NITROGEN PADA PUPUK NPK PADAT BERBASIS UREA
DOI:
https://doi.org/10.24843/JCHEM.2026.v20.i01.p13Abstract
NPK fertilizer, comprising Nitrogen, Phosphorus, and Potassium, is crucial for enhancing soil fertility and plant growth, particularly in the synthesis of proteins, amino acids, and chlorophyll. Precise and accurate testing methodologies are essential to ensure optimal Nitrogen content. This study modified the SNI 2803:2012 method for Nitrogen content determination by omitting the addition of Salicylic Acid, employing the IK-LAB-0401 method developed by the Pupuk Kujang Laboratory. Validation of the IK-LAB-0401 method was conducted by comparing it with the SNI 2803:2012 method through the determination of precision, accuracy, t-test, F-test, and uncertainty estimation. The results demonstrated that the precision of the SNI 2803:2012 and IK-LAB-0401 methods was 0.97 and 0.89, respectively, both lower than 2/3 of the Horwitz CV (1.78). The accuracy of the two methods was 98.96% and 98.02%. The t-test and F-test revealed no significant difference between the two methods. The uncertainty estimations for the two methods were ±0.31 and ±0.28. Based on the validation results, the IK-LAB-0401 method was validated and deemed suitable for determining the Nitrogen content in urea-based NPK fertilizer.
Keywords: NPK Fertilizer, Nitrogen, Salicylic Acid, Kjeldahl, Validation
Abstrak
Pupuk NPK, yang mengandung Nitrogen, Fosfor, dan Kalium, sangat penting untuk meningkatkan kesuburan tanah dan pertumbuhan tanaman, terutama dalam pembentukan protein, asam amino, dan klorofil. Untuk memastikan kandungan Nitrogen yang optimal, diperlukan metode pengujian yang presisi dan akurat. Penelitian ini memodifikasi metode SNI 2803:2012 untuk penentuan kadar Nitrogen dengan menghilangkan penambahan Asam Salisilat, menggunakan metode IK-LAB-0401 yang dikembangkan oleh Laboratorium Pupuk Kujang. Validasi metode IK-LAB-0401 dilakukan dengan membandingkannya dengan metode SNI 2803:2012 melalui penentuan presisi, akurasi, uji T, uji F, dan estimasi ketidakpastian. Hasil penelitian menunjukkan bahwa presisi metode SNI 2803:2012 dan IK-LAB-0401 masing-masing adalah 0,97 dan 0,89, lebih rendah dari 2/3 CV Horwitz (1,78). Akurasi kedua metode adalah 98,96% dan 98,02%. Uji T dan uji F menunjukkan tidak ada perbedaan signifikan antara kedua metode. Estimasi ketidakpastian untuk kedua metode adalah ±0,31 dan ±0,28. Berdasarkan hasil validasi, metode IK-LAB-0401 terbukti valid dan dapat digunakan untuk menentukan kadar Nitrogen dalam pupuk NPK berbasis urea.
Kata kunci: Pupuk NPK, Nitrogen, Asam Salisilat, Kjeldahl, Validasi
References
Alamsjah, M. A., Tjahjaningsih, W., & Pratiwi, A. W. 2009. Pengaruh Kombinasi Pupuk NPK Dan TSP Terhadap Pertumbuhan, Kadar Air Dan Klorofil A Gracilaria verrucosa. Jurnal Ilmiah Perikanan dan Kelautan, 1(1): 103–116.
Amin, M., & Flowers, T. H. 2004. Evaluation of Kjeldahl Digestion Method. Journal of Research (Science), 15(2): 159–179.
AOAC. 2016. Association of Official Analytical Chemists. Appendix F: Guidelines for Standard Method Performance Requirements. AOAC International and Official Methods of Analysis. Users.
AOAC. 2023. Fertilizers AOAC Association of Official Analytical Chemists (hal. 7015). Office of Indiana State Chemist, Purdue University.
BSN. 2012. Dokumen SNI 2803:2012 tentang SNI Pupuk NPK Padat. Badan Standardisasi Nasional.
CIPAC. 2003. Guidelines on method validation to be performed in support of analytical methods for agrochemical formulations.
Eurachem. 2014. The Fitness for Purpose of Analytical Methods. In Eurachem Guide, ISBN: 0-94948926-12-0.
http://www.eurachem.org/images/stories/Guides/pdf/valid.pdf
Galloway, J. N., Townsend, A. R., Erisman, J. W., Bekunda, M., Cai, Z., Freney, J. R., Martinelli, L. A., Seitzinger, S. P., & Sutton, M. A. 2008. Transformation of the nitrogen cycle: Recent trends, questions, and potential solutions. Science, 320(5878): 889–892.
https://doi.org/10.1126/science.1136674
Goh, K. J. K., Härdter, R., & Hardter, R. 2010. General Oil Palm Nutrition. Oil palm: Management for large and sustainable yields. Potash & Phosphate Institute and International Potash Institute, 191–230.
Greenwood, N. N., & Earnshaw, A. 1997. Chemistry of Elements_Book. School of Chemistry, University of Leeds, U.K.
Havlin, J. L., Tisdale, S. L., Nelson, W. L., & D., B. J. 2017. Acidity and Alkalinity. In Rules of Thumb for Petroleum Engineers.
https://doi.org/10.1002/9781119403647.ch8
ISO. 2009. Food and feed products — General guidelines for the determination of nitrogen by the Kjeldahl method. Geneva: International Organization for Standardization., ISO 1871:2009, 0–7.
Miller, J. N., & Miller, J. C. 2010. Statistics and Chemometrics for Analytical Chemistry. In Technometrics: 6(4): -.
https://doi.org/10.1198/tech.2004.s248
NATA. 2018. General accreditation guidance —validation and verification of quantitative and qualitative test methods. General Accreditation Guidance, January: 1–31.
https://nata.com.au/files/2021/05/Validation-and-Verification-of-Quantitative-and-Qualitative-Test- Methods.pdf
Stalcup, H., & Williams, R. W. 1955. Volumetric Determination of Nitrocellulose and Nitroguanidine By Transnitration of Salicylic Acid. Analytical Chemistry, 27(4): 543–546.
https://doi.org/10.1021/ac60100a015
Tando, E. 2018. Upaya Effisiensi dan Peningkatan Ketersediaan Nitrogen Dalam Tanah serta Serapan Nitrogen Pada Tanaman Padi Sawah (Oryza sativa L.). Buana Sains, 18(2): 171–180.
https://doi.org/10.33366/bs.v18i2.1190
Wiyantoko, B., Kurniawati, P., & Purbaningtias, T. E. 2017. Pengujian Nitrogen Total, Kandungan Air Dan Cemaran Logam Timbal Pada Pupuk Anorganik Npk Padat. JST (Jurnal Sains dan Teknologi), 6(1): 51–60.
https://doi.org/10.23887/jst-undiksha.v6i1.9439
Yusmayani, M., & Asmara, A. P. 2019. Analisis Kadar Nitrogen Pada Pupuk Urea, Pupuk Cair Dan Pupuk Kompos Dengan Metode Kjeldahl. Amina, 1(1): 28–34.
