الفهرس 
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Abstract
A rapid and sensitive immunochromatographic lateral flow kit (LFK) has been developed for detection of β-lactam antibiotic residues in milk. The developed LFK is based on a competitive format using antibiotic-specific polyclonal antibodies. Specific antibodies were raised in rabbits against β-lactam antibiotics, namely Amoxicillin (AMX)-KLH and Penicillin-G (Pen G)-KLH conjugates. The prepared anti-β lactam antibodies were conjugated with gold chloride nanoparticles and used in the development of competitive lateral flow kits for detection of β-lactams residues antibiotics in milk. The concentration of the gold chloride-antibody conjugate in the conjugation bad was adjusted to catch β-lactams antibiotics in milk that exceeds the permissible limits (4µg/L). In the developed kit the β- lactam antibiotics conjugated with KLH was placed in the test line and it competes with the free β-lactam antibiotics in tested sample for the gold chloride anti-β lactam antibodies conjugate in the conjugate pad. The control line of the lateral flow kits was coated with goat anti-rabbit antibodies. If the tested milk sample contains higher antibiotic level that exceed the permissible limits (4µg/L) it will be consumed by reaction with the gold anti-β lactam antibodies conjugate in the conjugation pad and the test line read negative with no color development. while if the tested samples contain β-lactams antibiotics lower than the permissible limits, it will not consume the whole conjugate from the conjugate pad that will in turn reacts with the β-lactam antibiotic in the test line producing deep ruby red color. The results could be accomplished within 6-8 minutes without the need of any other equipment. The lowest limit of β-lactams antibiotics detection by the developed kit was 10ppb in skimmed milk and 5ppb in phosphate buffer saline. Seventy-five cattle milk samples were examined by the developed kit and by the commercially available SNAP β-Lactam test kit as a gold standard test. The results were compared, and the determined specificity, sensitivity and validity of the locally prepared β-lactam antibiotics detection kit were 93.7%, 95.3% and 94.6%, respectively.