Application of silica extracted from rice husk ash for the encapsulation of AFB1 antibody as a matrix in immunoaffinity columns

The extraction of silica from rice husk ash (RHA) for the encapsulation of aflatoxin B1 antibody (Ab-AFB1) and its application as a matrix in immunoaffinity columns (IACs) were achieved. The RHA extraction was performed using 4 M NaOH, which yielded sodium silicate (Na2SiO3) for the synthesis of silica gel. The obtained silica was used for encapsulating Ab-AFB1 using the sol-gel technique. One milliliter of 1 M Na2SiO3:H2O:H3PO4 (0.43:0.11: 0.46) could generate silica gel that was suitable for encapsulating 1.36 mg of Ab-AFB1 at pH 7. After 48 hours of aging, the silica gel modified with AbAFB1 (SG-Ab-AFB1) was ground, and packed as the matrix in the IAC for aflatoxins purification. The modified silica gel was characterized using FTIR and SEM. The properties of IAC with SG-Ab-AFB1 were investigated by evaluating AF recovery, binding capacity, and reusability. The recovery of AFB1 was 94.11 ± 4.62%. In addition to AFB1 recovery, the column also retained AFB2, AFG1, and AFG2 with recovery values of 98.22 ± 3.74%, 92.22 ± 7.62%, and 83.00 ± 6.31%, respectively. This column, which contained 0.5 g of SG-AbAFB1 had a binding capacity of approximately 50 ng of AFs per column, and could be reused at least 5 times with a recovery of more than 80%.