Verification of the Walkley Black Method Test for Determination of Organic Carbon Elements in Palm Oil Empty Fruit Bunch Waste Fertilizer

: Many solid wastes from palm oil processing are empty fruit bunches, but their utilization is still limited. o ne of the uses of Oil Palm Empty Fruit Bunches ( OPEFB ) is organic fertilizer. The organic carbon method was verified on organic fertilizer from OPEFB waste using a UV-Vis Spectrophotometer. This study aims to verify the method of testing organic carbon on OPEFB fertilizer. Determination of carbon content in OPEFB fertilizer refers to the Association of Analytical Communities (AOAC) with the Walkley Black method. The results of the organic carbon test on OPEFB fertilizer show that the correlation coefficient (r) obtained is 100% , and the % RSD value of 0.40% means that the value is below 2/3 CV Horwitz of 4.72. accuracy with a value of 106.99%. The LOD is 2.45, and the LOQ is 8.17. Therefore, the limit value of the instrument is obtained by the LOD value of 2.49 and the LOQ of 8.32; the test results obtained indicate that it has complied with the conditions with acceptance. The test results for determining organic carbon in OPEFB fertilizer using the Walkley Black method showed valid results, so the method can be used to test organic carbon levels in OPEFB fertilizer.