Development of an enzyme-linked immunosorbent assay specific to Sudan red I.
To obtain antibodies to develop an enzyme-linked immunosorbent assay (ELISA) for the analysis of Sudan red I, haptens were designed and synthesized via four different strategies: (i) attachment of a spacer at the para position of the benzene ring, (ii) attachment of a spacer at the naphthol part, (iii) attachment of a spacer at the hydroxyl group of the Sudan red I molecule, and (iv) use of a fragment of the target molecule. A total of 10 haptens were used to generate immunogens, coating antigens, and polyclonal antibodies. One of the heterologous ELISAs developed exhibited an IC(50) of 1.6 ng/ml, a limit of detection (LOD) of 0.03 ng/ml, and a dynamic range between 0.1 and 14 ng/ml. The assay had 13% cross-reactivity with Para red and negligible cross-reactivity with other structure-related compounds. This ELISA was much more specific than those published previously. This assay was used to determine Sudan red I residues in tomato sauce and chili powder samples after simple pretreatment. The results were validated by comparison with high-performance liquid chromatography (HPLC). The average recoveries of Sudan red I by ELISA and HPLC were in ranges of 70-97% and 82-114%, respectively, indicating suitability of the developed ELISA for screening of Sudan red I in foods.
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Ting
T
Xu
Ke Yi
KY
Wei
Jia
J
Wang
Sergei A
SA
Eremin
Shang Zhong
SZ
Liu
Qing X
QX
Li
Ji
J
Li
D000906:Antibodies / Q000276:immunology; D001391:Azo Compounds / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005504:Food Analysis / Q000379:methods; D005506:Food Contamination; D006241:Haptens / Q000737:chemistry
D000906:Antibodies; D001391:Azo Compounds; D006241:Haptens; C033003:sudan red