免疫亲和柱净化-高效液相色谱-三重串联四级杆质谱法测定食用植物油中的黄曲霉毒素B1

建立了免疫亲和柱净化-高效液相色谱-三重串联四级杆质谱法测定食用植物油中黄曲霉毒素B1的方法。采用70%甲醇水溶液提取食用植物油中黄曲霉毒素B1,提取液经过滤、免疫亲和柱净化后,上高效液相色谱-三重串联四级杆质谱仪进行测定。结果表明,黄曲霉毒素B1在0.2~10 ng/mL范围内方程线性关系良好,方法检出限(S/N=3)为0.05μg/kg,定量限(S/N=10)为0.2μg/kg,平均加标回收率在83.0%~94.8%之间,相对标准偏差小于7.8%。     

植物油黄曲霉毒素B_1含量的检测及能力验证

用酶联免疫法测定食用植物油中黄曲霉毒素B1,对酶联免疫法前处理条件进行了优化,结果表明,选择一步萃取与甲醇水溶液(7+3)提取相结合的方法,回收率较理想,在0.1~2.0μg/kg浓度范围内,黄曲霉毒素B1具有良好的线性关系,方法检出限为1.0μg/kg,加标回收率为101.3%~104.3%,精密度试验RSD为1.04%~3.16%,并将建立的方法应用于2012年和2013年度植物油中黄曲霉毒素B1的能力验证,结果|Z|比分数均远远小于2,取得了满意的结果。酶联免疫法操作简单,分析速度快,因此可广泛应用于食用植物油中黄曲霉毒素B1检测。     

食品中黄曲霉毒素B1、B2、G1、G2的高效液相色谱测定方法

为建立同时测定食品中黄曲霉毒素B1、B2、G1、G2的高效液相色谱测定方法，将碾磨后的试样经乙腈＋水溶液提取、过滤后，以MycoSep^TM净化柱净化，吹干净化液后，加入正己烷和三氟乙酸溶液衍生，反相色谱柱测定。黄曲霉毒素B1、B2、G1、G2能达到完全的基线分离，检出限分别为0．012、0．008、0．036和0．024μg／kg，不同水平的加标回收率均达80％以上，RSD均小于3．0％。该方法快速、准确、灵敏，有利于试验者安全，能同时分离食品中黄曲霉毒素B1、B2、G1、G2。     

高效液相色谱-串联质谱法同时测定花生制品中的黄曲霉毒素B1、B2、G1、G2

采用高效液相色谱-串联质谱建立了高效液相色谱-串联质谱法同时测定花生制品中4种黄曲霉毒素(B1、B2、G1、G2)的方法.结果表明,在ESI正离子模式下,高效液相色谱-串联质谱法的最低检出限为0.2μg/kg,定量限为0.6 μg/kg;标准工作液在0.5～50.0μg/kg的范围内线性良好,相关系数达到0.9990.     

免疫亲和柱同时净化-HPLC法测定植物油中黄曲霉毒素和玉米赤霉烯酮

建立了免疫亲和柱同时净化-高效液相色谱法检测植物油中的黄曲霉毒素B1、B2、G1、G2和玉米赤霉烯酮的分析方法。黄曲霉毒素B1、B2、G1、G2的方法的定量限均为0.1μg/kg,玉米赤霉烯酮的方法的定量限为5.0μg/kg,相对标准偏差低于10.4%,回收率为82.0%～95.5%。该方法简便快速、灵敏准确、重现性好,可以用于对植物油中黄曲霉毒素B1、B2、G1、G2和玉米赤霉烯酮进行快速定量检测。      

冷冻-离心净化-高效液相色谱法测定植物油中黄曲霉毒素B1

通过冷冻-离心净化,建立了高效液相色谱定量测定植物油中黄曲霉毒素B1的方法,并将其用于测定市场上30批植物油产品中黄曲霉毒素B1的含量。以水/乙腈溶液为提取剂对植物油中黄曲霉毒素B1进行萃取,低温冷冻固化植物油,冷冻离心使植物油和提取液分离、净化提取液,经衍生后上液相色谱进行定量分析。优化的乙腈/水提取液配比为90:10,低温冰箱冷冻温度为-12 ℃,冷冻离心转速为12000 r/min、离心力约为1.4万 × g,以水浴加热的方式进行衍生。方法的定量检出限为0.02 μg/kg,校准曲线回归方程为y=2.321987x＋0.001377,相关系数（R2）为0.9997,在0.10～5.0 μg/L范围内线性关系良好。当样品中黄曲霉毒素B1添加量为0.5、1.0、5.0 μg/kg时,平均回收率为80.2%～93.2%,相对标准偏差为2.9%～4.7%（n=6）,均优于免疫亲和柱净化处理的结果。市售植物油产品中黄曲霉毒素B1的浓度范围为< LOD至5.72 μg/kg,均低于GB 2761—2017中对该指标的限值,花生油和玉米油中黄曲霉毒素B1均有检出,油茶籽油和核桃油中黄曲霉毒素B1均低于检出限。该方法样品前处理简便、稳定性好、检出限低,适合植物油中黄曲霉毒素B1的批量检测。     

QuEChERS-高效液相色谱-柱后光化学衍生法测定粮谷类食品中黄曲霉毒素

目的 建立了QuEChERS-高效液相色谱-柱后光化学衍生法测定粮谷类食品中黄曲霉毒素B1、B2、G1、G2的分析方法。方法 样品经过1%甲酸-乙腈提取,MgSO4+C18+PSA净化,高效液相色谱柱后光化学衍生化法检测。结果 4种黄曲霉毒素在(0.5~20)或(0.125~5) μg/L范围内线性关系良好,相关系数均大于0.999,方法检出限为0.1~0.3 μg/kg,定量限为0.3~1.0 μg/kg,加标回收率为86.4%~97.8%,RSD为2.9%~6.3%。结论 该方法前处理简便,回收率稳定,测定结果准确,成本低廉,可用于粮谷类食品中黄曲霉毒素的大批量检测。     

测定花生油中黄曲霉毒素B1前处理方法的优化

目的 建立一种环保的同时适用于高效液相色谱柱后光化学衍生法(liquid chromatography post-column photochemical derivation, LC-PSD)和酶联免疫吸附筛查法(enzyme-linked immunosorbent screening, ELISA)测定花生油中的黄曲霉毒素B1的前处理净化方法。方法 花生油试样经甲醇-水溶液(70:30, V:V)提取, 经乙醚净化、冷冻离心除脂净化和免疫亲和柱净化后, 采用LC-PSD法和ELISA法测定。结果 黄曲霉毒素B1在0.1~40 ng/mL范围内均表现出良好的线性关系, LC-PSD法相关系数均大于0.999, 检出限为0.03 μg/kg, 定量限为0.1 μg/kg。ELISA法相关系数均大于0.9346, 检出限为0.1 μg/kg, 定量限为0.3 μg/kg, 均满足现行国标要求。黄曲霉毒素B1在添加水平为5 μg/kg和20 μg/kg时, LC-PSD法的加标回收率为84%~99%, 不确定度(n=6)为0.2%~3.3%, ELISA法的加标回收率为109%~124%, 不确定度(n=6)为0.3%~10.9%。结论 优化后的花生油中黄曲霉毒素B1检测前处理方法可以使检验效率提高40%以上, 有机溶剂的使用量降低50%以上, 经济效益提高50%以上, 优化方法适合大批量测定花生油中黄曲霉毒素B1。     

免疫亲和柱净化-光化学衍生高效液相色谱荧光法测定植物油中黄曲霉毒素B1的含量

建立了免疫亲和柱净化-光化学衍生高效液相色谱荧光法测定植物油中黄曲霉毒素B1含量的方法,并对样品的测定条件进行了优化。结果表明:植物油的称样量缩减为5.00 g,黄曲霉毒素B1测定结果与GB/T 18979—2003测定结果基本吻合;工作曲线在1~40 ng/mL质量浓度范围内具有良好的线性关系,相关系数为0.999 9,方法检出限为0.3μg/kg;在空白样品中添加低、中、高3个不同添加量水平的黄曲霉毒素B1标准品,其回收率在90.5%~99.8%之间,相对标准偏差在6.3%~9.8%之间。采用光化学衍生,操作简单,无需衍生剂,避免了柱前衍生和柱后衍生受衍生剂浓度、温度、反应时间的影响,所建立的方法适用于植物油中黄曲霉毒素B1含量的测定。     

免疫亲和柱同时净化-HPLC法测定植物油中黄曲霉毒素和玉米赤霉烯酮

建立了免疫亲和柱同时净化-高效液相色谱法检测植物油中的黄曲霉毒素B1、B2、G1、G2和玉米赤霉烯酮的分析方法.黄曲霉毒素B1、B2、G1、G2的方法的定量限均为0.1 μg/kg,玉米赤霉烯酮的方法的定量限为5.0μg/kg,相对标准偏差低于10.4％,回收率为82.0％ ～95.5％.该方法简便快速、灵敏准确、重现性好,可以用于对植物油中黄曲霉毒素B1、B2、G1、G2和玉米赤霉烯酮进行快速定量检测.     

Co-occurrence of aflatoxins B 1 , B 2 , G 1 , G 2 , zearalenone and fumonisin B 1 in Brazilian corn

Two hundred and fourteen unprocessed corn samples (1997-98 harvest), collected at wholesale markets in different regions in Brazil, were surveyed for the occurrence of mycotoxins. The samples were analysed for aflatoxins B 1 , B 2 , G 1 , G 2 , zearalenone and fumoni1sin B 1 using in-house validated methods. The occurrence of aflatoxin B 1 , zearalenone and fumonisin B 1 was found in 38.3, 30.4 and 99.1% of the samples, respectively. Aflatoxin B 1 , zearalenone and fumonisin B 1 contamination levels varied from 0.2 to 129, 36.8 to 719, and 200 to 6100 μg/kg, respectively. The cooccurrence of the two carcinogenic mycotoxins aflatoxin B 1 and fumonisin B 1 was observed in 100% of the aflatoxin-contaminated samples (82 samples). Cooccurrences of aflatoxin B 1 : zearalenone: fumonisin B 1 and aflatoxin B 1 : aflatoxin B 2 : fumonisin B 1 were found in 18 and 43 samples, respectively.     

Occurrence of aflatoxins B 1 , B 2 , G 1 and G 2 in some Brazilian pet foods

The presence of cereals and grains in the formulation of pet foods suggests the need to control aflatoxin contamination in these foods. The objective of the study was to analyse domestic pet food to determine the occurrence of aflatoxins as well as their risk to animal health. One hundred food samples (45 for dogs, 25 for cats, 30 for birds) were collected at random from pet shops in Alfenas city, south-east Brazil. Thin-layer chromatography was used for separation, identification and quantification of the compounds after validation of the method. Aflatoxins were detected in 12.0% of the samples. Levels of aflatoxins (B 1 + B 2 + G 1 + G 2 ) above the maximum limit established in Brazil (50 µg kg -1 ) for animal food were detected in five of the 12 positive samples (41.7%). The concentration of total aflatoxins was 15-374 µg kg -1 (mean 131 µg kg -1 ). All samples containing peanuts were positive for aflatoxin B 1 . Aflatoxins are carcinogenic and their consumption might be a risk for domestic animal health. The high prevalence of aflatoxin B 1 in foods prepared for birds, species highly susceptible to aflatoxins, shows the need for the re-evaluation of the use of peanuts (present in seven of the eight samples positives for aflatoxin) and/or the addition of fungicides to the food.     

Survey of breakfast and infant cereals for aflatoxins B1, B2, G1 and G2.

Three hundred and forty-nine breakfast and infant cereal samples were collected at retail level across Canada from 2002 to 2005. They included rice-, soy-, barley-based and mixed-grain infant cereals, corn-, wheat-, rice-based and mixed-grain breakfast cereals, and were analysed for aflatoxins B1, B2, G1 and G2 using a modified AOAC International official method. An immunoaffinity column was used for the cleanup and purification of extracts. Determination of aflatoxins was by LC using post-column derivatization with pyridinium hydrobromide perbromide and fluorescence detection. Results indicated that 50% of both breakfast and infant cereals had detectable levels (limit of detection = 0.002 ng g-1) of aflatoxin B1, which is the most toxic of the four toxins. The levels found varied from 0.002 to 1.00 ng g-1 for aflatoxin B1, from 0.002 to 0.14 ng g-1 for aflatoxin B2, from 0.008 to 0.27 ng g-1 for aflatoxin G1, and from 0.008 to 0.048 ng g-1 for aflatoxin G2. Only 4% of the breakfast cereals and 1% of the infant cereals had aflatoxin B1 levels exceeding 0.1 ng g-1, which is the European Union maximum limit for aflatoxin B1 in baby foods and processed cereal-based foods for infants and young children.     

Biocontrol of aflatoxins B1, B2, G1, G2, and fumonisin B1 with 6,7-dimethoxycoumarin, a phytoalexin from Citrus sinensis

Phytoalexins (stress-induced compounds) from Citrus sinensis cultivar Valencia were screened for antifungal and antimycotoxic activity against a test organism (Cladosporium cladosporoides) and mycotoxin-producing fungi Fusarium verticillioides and Aspergillus parasiticus. The active compound, a member of the coumarin family of compounds, has antifungal and antimycotoxic activities and was chemically identified. High-performance liquid chromatography results indicated that Valencia oranges contain a trace amount (0.36 microg/g) of scoparone in untreated fruit, but concentrations increased in UV-irradiated fruit (15.2 microg/g). Infection with Penicillium digitatum, a natural spoilage mold of citrus fruit, caused a 35.51-microg/g increase in the phytoalexin. UV absorption, infrared absorption, and 1H nuclear magnetic resonance spectroscopy revealed that this phytoalexin is identical to 6,7-dimethoxycoumarin. This is the first report indicating that the stress-induced compound, 6,7-dimethoxycoumarin, isolated from P. digitatum-infected Valencia fruit confers resistance against the mycotoxigenic fungi A. parasiticus and F. verticillioides and causes a reduction in production of fumonisin B1 and aflatoxins G1, G2, B1, and B2.     

Occurrence of aflatoxins (B1, B2, G1, G2) in herbal tea consumed in Turkey

Aflatoxin contents in 12 types of herbal teas were determined by high performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. Forty eight samples were collected from four local herbal shops in Manisa, Turkey. Of the 48 samples analyzed, 43 were aflatoxin positive. The highest concentration of aflatoxin (34.18 µg/kg) was determined in a sample of camomile tea. The occurrence of AFB1, B2, G1 and G2 was found in samples at levels of 54, 29, 71 and 46 %, respectively. Aflatoxin B1, B2, G1 and G2 contamination levels varied from 0 to 14.2, 0 to 12.4, 0 to 13.5 and 0 to 28.7 µg/kg, respectively. Aflatoxin was not detected in five samples consisting of linseed, lime and fennel tea.     

柱前衍生-高效液相色谱法检测食品中的黄曲霉毒素B_1、B_2、G_1、G_2

目的:改进柱前衍生-高效液相色谱法测定食品中的黄曲霉毒素B1、B2、G1、G2。方法:分别用甲醇-水(8∶2,v∶v)或二氯甲烷提取食品中的黄曲霉毒素。提取液经免疫亲和柱净化后,采用三氟乙酸(或甲酸)进行衍生,并利用高效液相色谱仪进行测定。结果:黄曲霉毒素B1、B2、G1、G2的检出限分别为0.2、0.2、0.2、0.2μg/kg;在低、中、高加标浓度下的回收率分别为81.0%~94.1%、75.6%~92.0%、75.0%~92.4%、77.6%~91.3%。结论:改进后的柱前衍生-高效液相色谱法克服了样品基质的干扰,测定结果更准确。     

HPLC-柱后光化学衍生法检测花生酱中黄曲霉毒素

建立高效液相色谱-在线柱后光化学衍生-荧光检测器检测花生酱中黄曲霉毒素B1、B2、G1、G2的含量。样品以乙腈-水(80∶20)溶液提取,经免疫亲和柱净化后,利用在线柱后光化学衍生-HPLC-FLD进行分析测定。结果:在优化条件下,黄曲霉毒素B1、G1在0.30 mg/L~10 mg/L,黄曲霉毒素B2、G2在0.06 mg/L~3.0mg/L线性关系良好,r0.998,回收率80%~101%,RSD5.9%。黄曲霉毒素B1、B2、G1、G2的检测限(LOD)分别为0.10、0.03、0.15、0.04μg/kg。     

Aflatoxins in Foods and Feedstuffs. Part 2. Determination of the aflatoxin B1, B2, G1 and G2 contents in Grain crops1

The simple method for determination of small amounts of aflatoxins (about 5–10 μg/kg) was described. The method was adopted for wheat, barley, rye and oats. Difficulties of aflatoxins determination in cereals are discussed, mainly observed during purification of extracts and resolution by TLC. Different tests were compared for confirmation of aflatoxins in cereals. Results of cereal crops control for contamination with aflatoxins are presented.