以发光二极管(LED)为激发光源,光纤光谱仪为检测设备,构建了LED激发的小型荧光光谱检测装置;利用三溴化吡啶衍生黄曲霉毒素B₁(AFB₁)产生强荧光信号,提出了快速测定玉米粉中AFB₁含量的方法。称取5 g样品,加入25 mL 80%(体积分数)甲醇溶液和1.0 g氯化钠粉末,超声提取20 min,过滤。分取5 mL滤液,过C₁₈固相萃取小柱,得到澄清透明溶液。分取2 mL,加入1 mL 200 mg·L^-1三溴化吡啶溶液,于60 ℃恒温衍生反应4 min。在LED激发波长370 nm下,记录体系在429 nm处的荧光强度。结果表明:AFB₁质量浓度在10~500 μg·L^-1内与体系荧光强度呈线性关系,检出限(3s/k)为3.47 μg·L^-1;对实际样品进行加标回收试验,AFB₁回收率为80.1%~109%,测定值的相对标准偏差(n=5)为2.4%~7.7%。

A light-emitting diode (LED) excited micro fluorescence spectrum detection device was constructed with LED as the excitation light source and optical fiber spectrometer as the detection equipment. Aflatoxin B₁ (AFB₁) could produce strong fluorescence signal after pyridine tribromide derivation, and a method for the rapid determination of AFB₁ in corn meal was proposed. The sample (5 g) was taken, and 25 mL of 80% (volume fraction) methanol solution and 1.0 g of sodium chloride powder were added. The mixture was extracted ultrasonically for 20 min and filtered, and an aliquot (5 mL) of the filtrate was taken and passed through C₁₈ cartridge. An aliquot (2 mL) was taken, and 1 mL of 200 mg·L^-1 pyridine tribromide solution was added, and the derivative reaction was conducted at 60 ℃ for 4 min. The fluorescence intensity of the system at 429 nm was recorded under the LED excitation wavelength of 370 nm. It was shown that linear relationship between mass concentration of AFB₁ and fluorescence intensity of the system was kept in the range of 10-500 μg·L^-1, with detection limit (3s/k) of 3.47 μg·L^-1. Test for recovery was made on the actual sample, and the recoveries of AFB₁ were in the range of 80.1%-109%, with RSDs (n=5) of the determined values ranged from 2.4% to 7.7%.