Study On Immunolatex Techenology For The Rapid Detection Of Aflatoxin B₁

Aflatoxin B1 are fungi toxin produced by Aspergillus parasiticus and A. flavu, they are carcinogenic and can be present in grains, nuts, cottonseed and other commodities associated with human food or animal feeds, Aflatoxin B₁ have been implicated in human health and animal feeds. So, Most controlling government agencies worldwide have regulations regarding the amount of aflatoxin B₁ allowed in human and animal foodstuffs, and detect it as compellent standard.Carboxylated polystyrene latex particles (CPLP) were prepared by soap-free polymerization with styrene as a monomer andα-methyl crylic acid as a modifier. Then BALB/c mice were injected with BSA and antibody against BSA was obtained. After sensitized conditions were studied, the CPLP were sensitized with aflatoxin B₁ oxime-BSA (AFB₁O-BSA) for the detection of aflatoxin B₁ (AFB₁). Main research contents were followed:1 Preparation of carboxylated polystyrene latex particles (CPLP)The CPLP were prepared by adding modifier (α-methyl crylic acid) into styrene. CPLP were prepared by soap-free polymerization with styrene as monomer and m-methyl crylic acid as modifier, the effects of concentration of modifier, polymerization time and temperature were studied. The results showed that the CPLP which modified byα-methyl crylic acid stabler than polystyrene latex particles(PLP). When concentration of modifier increased to 10% of styrene that the CPLP latex was stablest. The conversion of styrene was 92% when polymerization reacted at 75℃for 12 h, the diameters of CPLP were 240 nm and the latex did not deposit after stored at room temperature for 15 d.2 Optimization on the Sensitized Conditions of CPLP BALB/c mice were injected with BSA, and the antibody against BSA was obtained. CPLP sensitized with bovine serum albumin(BSA) were chequerboard titrated by antibody against BSA, and effects of sensitized conditions on latex agglutination test were studied. The results showed that 0.05 mol/Land pH8.0 phosphate-buffer saline diluted latex to 1.0% and 0.5 mg/mL BSA was added into it, then sensitized for 30 min at 37℃and it could establish the best latex agglutination with antibody (titer 1:40,000) diluted 1: 160.3 Preparation of Latex for the Rapid Detection of Aflatoxin B₁The AFB₁ minimum detecting limit of the sensitized latex was 5 ng/mL and that reagent was stored at 4℃and -20℃respectively for 3 months after appropriate pre-treatment, the qulity of reagent stored at 4℃was good, and it gone bad at -20℃. It could be applied to detect aflatoxin B1 qualitatively and half-quantitatively in fieldwork for its characteristics such as minim, simpleness, rapidness and specificity.