| A fluorescent latex immunochromatographic assay for the detection of ractopamine residues in pork was established based on competition principle.Fluorescent latex particles were marked with anti-RAC monoclonal antibody(McAb）,the conjugate was sprayed onto the conjugate pad.Then goat anti-mice IgG and the artificial antigen RAC-BSA were prepared and jet-positioned onto nitrocellulose(NC）membrane as the control line(C)and the test line(T),respectively.Sample pad,conjugate pad,nitrocellulose membrane and absorbent paper were assembled in turn and cut into detecting strips.The more the RAC exists in the sample,the more effectively it would bind to the limited amount of fluorescent latex particles-marked anti-RAC McAb competed with RAC-BSA,and the test line would be darker simultaneously under UV-light.The brightness of the fluorescence band could indicate a semi-quantitative result intuitively.The minimum limit of the strips could reach 0.5 μg/L for the detection of RAC in pork sample，without any cross-reactions with clenbuterol(CL） and salbutamol(SAL）.The fluorescent latex immunochromatographic assay could be used in the rapid and simple screening test for ractopamine residues in pork with its low cost, high stability and sensitivity. |