Application of an enzyme immunoassay for the quantitative determination of azo dye (Orange II) in food products.
This paper reports the preparation of polyclonal antibodies against a synthetic azo dye, Orange II, and the development of an indirect ELISA to detect Orange II in foods. The sulfonic group of Orange II was modified and linked with carrier protein to synthesise an artificial antigen. Based on the checkerboard titration, the method showed excellent sensitivity (IC₅₀ = 0.61 ng g⁻¹) to Orange II in the linear range of 0.05-10 ng g⁻¹. The antibody had little cross-reactivity with Chromotrope FB, Gardenia Yellow, Ponceau 4R, Sunset Yellow and Sudan dyes. The ELISA had limits of detection (LOD) of 0.22, 0.97 and 0.74 ng g⁻¹ in chilli powder, chilli oil and braised pork, respectively. The limits of quantification (LOQ) of the assay were 0.91 ng g⁻¹ in chilli powder, 1.48 ng g⁻¹ in chilli oil and 1.10 ng g⁻¹ in braised pork. For food products fortified with 1-10 ng g⁻¹ Orange II, the inter- and intra-assay variations were all less than 24.0% and 18.0%, respectively. Therefore, the proposed test could be used as a rapid screening method for Orange II detection in food samples.
College of Pharmacy, State Key Laboratory of Medicinal Chemical Biology and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin, China.
Huyin
H
Xue
Yue
Y
Xing
Yongmei
Y
Yin
Taichang
T
Zhang
Bo
B
Zhang
Yu
Y
Zhang
Pei
P
Song
Xi
X
Tian
Yinghui
Y
Xu
Peng
P
Wang
Meng
M
Meng
Rimo
R
Xi
D000818:Animals; D000918:Antibody Specificity; D001391:Azo Compounds / Q000032:analysis* / Q000737:chemistry; D001557:Benzenesulfonates / Q000032:analysis* / Q000737:chemistry; D002212:Capsicum / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005505:Food Coloring Agents / Q000032:analysis* / Q000737:chemistry; D005513:Food Inspection / Q000379:methods*; D005638:Fruit / Q000737:chemistry; D006241:Haptens / Q000737:chemistry; D057230:Limit of Detection; D008460:Meat / Q000032:analysis; D010938:Plant Oils / Q000737:chemistry; D015203:Reproducibility of Results; D017365:Spices / Q000032:analysis; D034421:Sus scrofa
D001391:Azo Compounds; D001557:Benzenesulfonates; D005505:Food Coloring Agents; D006241:Haptens; D010938:Plant Oils; C014722:2-naphthol orange