Diebold G J, Karny N, Zare R N, Seitz L M
J Assoc Off Anal Chem. 1979 May;62(3):564-9.
A 2-step chromatographic separation, using both thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC), in conjunction with the high sensitivity of laser fluorometry permits extension of the detection limits of aflatoxin contamination in corn to 0.1 ppb (microgram/kg) with a 26% root mean square variation. Aflatoxin B1 is extracted from corn with water-methanol and cleaned up by TLC. The recovery of aflatoxin from the TLC plates was linear from 10 to 1000 pg. Aflatoxin B1 is converted to the more highly fluorescent B2A derivative by treatment with 1N HCl. Experiments with aflatoxin B1 standard establish a constant conversion to B2A over approximately 3 orders of magnitude in B1 concentration. An extract of the B2A aflatoxin derivative is injected onto a reverse phase HPLC column. A flowing droplet of eluant is irradiated by an amplitude-modulated 325 nm He-Cd ion laser beam, and fluorescence from the droplet is detected by a lock-in amplifier in phase with the laser modulation. Several chromatograms are presented that demonstrate the capability of this procedure for removing interfering components in the corn extract.
采用两步色谱分离法，结合薄层色谱法（TLC）和高压液相色谱法（HPLC），并利用激光荧光法的高灵敏度，可将玉米中黄曲霉毒素污染的检测限扩展至0.1 ppb（微克/千克），均方根变化为26%。黄曲霉毒素B1用水 - 甲醇从玉米中提取，并用TLC进行净化。从TLC板上回收黄曲霉毒素的线性范围为10至1000 pg。通过用1N盐酸处理，黄曲霉毒素B1转化为荧光性更强的B2A衍生物。用黄曲霉毒素B1标准品进行的实验表明，在B1浓度约3个数量级的范围内，转化为B2A的转化率恒定。将B2A黄曲霉毒素衍生物的提取物注入反相HPLC柱。用振幅调制的325 nm氦镉离子激光束照射洗脱液的流动液滴，并通过与激光调制同相的锁相放大器检测液滴的荧光。给出了几张色谱图，展示了该方法去除玉米提取物中干扰成分的能力。
