A semiconductor nanomaterial was prepared and its degradation efficiency on zearalenone (ZEN) was investigated. The photocatalytic material, graphitic carbon nitride (g-C3N4), was synthesized by the conventional thermal cracking method, and its structure was analyzed by (X-ray diffraction) XRD, Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic degradation experiments showed that g-C3N4 induced photocatalytic effects under ultraviolet light (254 nm, including 185 nm), releasing reactive oxygen radicals to degrade ZEN. The experimental conditions for the photocatalytic degradation of ZEN were explored. The results showed that the degradation rate of ZEN was 96.0% when the mass of the photocatalytic material , the wavelength of the UV lamp, the initial concentration and the irradiation time were 20 mg, 254 nm (50 W), 0.5 μg/mL and 60 min, respectively. Meanwhile, the experimental conditions for the photocatalytic degradation of ZEN powder samples were optimized. The results showed that the degradation rate of ZEN was 80.0% when the mass of the photocatalytic material, the wavelength of the UV lamp, and the irradiation time were 800 mg, 254 nm (50 W) and 50 min, respectively. The results could provide a theoretical reference and practical basis for the photocatalytic degradation of ZEN.

In order to meet the needs of rapid quantitative detection of fumonisin B1 (FB1) in grains, this paper takes fumonisin B1 as the research object, and creates a rapid quantitative detection card of FB1 on the basis of time-resolved fluorescent nanospheres, with no need to adjust the PH of samples before detection. The detection performance of the detection card in grains (rice, corn, wheat) was analyzed and compared with enzyme-linked immunosorbent assay kit and high performance liquid chromatography. The LOD for different samples was in the range of 35.37~37.17 μg/kg, and the LOQ was 117.9~123.9 μg/kg, which meant good sensitivity; the linear range was 250~6 000 μg/kg, while the correlation coefficient R2 was in the range of 0.997 2~0.999 5; the spiking recoveries at 6 spiked levels in different samples were in the range of 83.38%~114.66%, with the coefficient of variation (CV) less than 15%, which meant good accuracy and repeatability. When the national standard liquid chromatography and FB1 fluorescence quantitative rapid detection card simultaneously detects different samples contaminated by FB1, the coincidence of the detection results was in the ranger of 92.53%~106.26%, with the CV less than 10.37%. The cross-reaction rate of other five common mycotoxins was less than 5%. Meanwhile, the difference between the spiked concentration and their average detected concentration was extremely significant, indicating good specificity. Hence, the FB1 fluorescence quantitative detection card prepared in this study could meet the needs of on-site rapid quantitative detection of fumonisin B1 in grains.

呕吐毒素又称脱氧雪腐镰刀菌烯醇(DON),化学名为3a 7a 15-三羟基草镰孢菌-9-烯-8-酮,属单端孢霉烯族化合物.玉米赤霉烯酮(ZEN)又称F-2毒素,化学名为6-(10-羟基-6氧基-1-碳烯基)β-雷琐酸-μ-内酯,是由玉米赤霉菌、禾谷镰刀菌(F.graminearum)、三线镰刀菌(F.tricinctum)及串珠镰刀菌等产生的一类真菌毒素.有研究显示,DON和ZEN广泛污染农作物、食品及饲料等植物性产品,这些毒素可以引起人类及动物的急性或慢性中毒,损害机体的肝脏、肾脏、神经组织、造血组织及皮肤组织等,并同时损害两个以上的器官和组织[1-2],每年因真菌毒素污染而造成的直接或间接损失达到数百亿美元[3].

选用不同水分梯度的稻谷、小麦和玉米样品,用不同型号的水分测试磨的不同档位进行粉碎处理,得到不同粉碎细度的样品,采用GB 5009.3-2016中的第一法直接干燥法测定其水分含量.结果表明:同一份样品在不同的粉碎细度下水分测定结果有差异,粉碎细度越高,水分含量越高,基本成正相关;A型水分磨的1～2档与B型水分磨的0档粉碎细度基本呈对应关系,测定结果基本一致.

研究了花生油、大豆油、芝麻油、大豆色拉油、花生色拉油食用油脂肪酸价的国标滴定法和双液相滴定法的不同,并作比较.向待测样品中加入乙醚:乙醇(2:1)混合液50 mL(国标法)或石油醚25 mL+75 mL50％乙醇混合溶液(双液相法),以酚酞为指示剂,以KOH为标准溶液滴定至下层溶液呈微红色,由于油脂的黄色色素不溶于水相,故在双液相法中不会干扰终点判断.试验结果表明:与国标法相比,双液相法的精密度和选择性更强,滴定终点的变化更加敏锐.

以粳稻谷为研究对象,分别采用两种不同型号的精米机,探讨了压铊档位、碾磨时间、筛孔大小对稻谷出米率的影响.结果 表明:选用2.0mm筛孔得到的出米率比2.5mm筛孔高出约1％～3％;LTJM160型精米机选择碾磨时间50 s压铊档位1档、BLH-3500型精米机选择碾磨时间45 s压铊档住2档时,2台精米机出米率结果存在一致性且检验结果相对稳定.