环糊精对花生黄曲霉毒素B_1荧光增强作用与应用研究

本文探讨了一种新型无毒的黄曲霉毒素荧光增强剂—β-环糊精及其衍生物。结果表明,在2mL黄曲霉毒素B1溶液中加入1mL0.01mol/Lβ-环糊精或其衍生物时荧光增强倍数最大,其中β-环糊精可使荧光信号增强5倍,2,6-二甲基-β-环糊精荧光增强倍数可达到8倍,表明β-环糊精及其衍生物对黄曲霉毒素荧光增强作用极为显著;利用该增强剂在黄曲霉毒素荧光增强前和荧光增强后的信号变化量和黄曲霉毒素浓度之间的线性关系建立了新型荧光增强剂免疫亲和柱荧光光度检测方法,最低检出限可达0.3μg/kg,相关系数都达到0.99以上;对花生样品的添加回收率在90%～120%之间;与基于高效液相色谱国家检测标准方法比对分析,两种检测方法无显著差异,相对误差小于4%,为黄曲霉毒素高灵敏快速检测技术开辟了新的途径。     

原位光化学衍生快速检测黄曲霉毒素荧光强度

通过优化有机溶剂种类和光化学衍生时间,建立采用光化学衍生进行前处理,并利用黄曲霉毒素原位衍生荧光检测仪快速检测黄曲霉毒素荧光强度的方法。结果表明,在光化学衍生时间为4 min时,70%甲醇溶剂中黄曲霉毒素B1和G1的光化学衍生荧光增强效果最显著,优于甲醇和乙腈;黄曲霉毒素B2和G2荧光强度最大且稳定,光化学衍生后无明显增强。该方法在0.1 ng/mL~20.0 ng/mL线性关系良好,R2>0.9984,方法检测限在0.15 ng/mL~0.37 ng/mL之间,检测时间短,操作简单方便,满足食品和中药材中黄曲霉毒素的快速检测要求。     

黄曲霉毒素的危害、限量标准及检测方法

<正>黄曲霉毒素的毒性非常高,是目前已发现霉菌毒素中毒性最大的一种。上海飞测基于领先的荧光定量FPOCT技术平台,开发出黄曲霉毒素荧光定量快速检测系统。黄曲霉毒素(Aflatoxins,简写AF)主要为黄曲霉和寄生曲霉的次生代谢产物。在温暖与潮湿的气候地区,凡是被黄曲霉和寄生曲霉污染过的粮食和饲料都可能存在黄曲霉毒素。最易受黄     

时间分辨荧光免疫层析试纸条在油料饼粕黄曲霉毒素B_1检测中的应用

采用黄曲霉毒素时间分辨荧光免疫层析试纸条及配套的时间分辨荧光速测仪,对油料饼粕中黄曲霉毒素B1的快速检测进行了应用研究。该时间分辨荧光免疫分析技术是基于时间分辨荧光免疫层析试纸条和载有Eu（Ⅲ）标记特异性单克隆抗体的样品瓶建立的检测技术。时间分辨荧光速测仪可内置标准曲线,直接输出检测结果。对6种油料饼粕做黄曲霉毒素B1添加回收率实验,回收率在70%~120%之间,批间、批内变异系数〈15%。在实际样品的检测中,时间分辨荧光免疫层析试纸条检测技术与液相色谱-串联质谱法相比,检测结果相对误差〈15%。时间分辨荧光免疫层析试纸条检测技术测定快速、准确,技术稳定、可靠,设备经济、小型,适用于大批量油料饼粕样品的快速检测和风险评估。     

一种快速检测产黄曲霉毒素菌株的方法

甲基化β-环糊精(Mβ-cyd)可以增强黄曲霉毒素的荧光强度,普通霉菌培养基中添加Mβ-cyd,产黄曲霉毒素的菌株接种在这种培养基上28℃培养5 d后,在365 nm的紫外灯下观察,若菌落周围有蓝紫色荧光即为产黄曲霉毒素菌株,产毒菌株经过产毒培养、毒素提取、高效液相色谱检测等一系列试验证明,这种方法可以有效地检测出产黄曲霉毒素菌株。     

荧光免疫分析技术检测食品中AFB1的研究进展

从不同的检测原理出发，将用于黄曲霉毒素B1的荧光免疫分析检测法分为4类：荧光免疫吸附法，基于荧光纳米颗粒的侧流免疫分析法，免疫磁分离荧光检测法和适配体免疫荧光分析法。总结荧光免疫技术检测食品中黄曲霉毒素B1的研究进展，并对需要克服的问题进行探讨，分析并展望其未来的发展趋势。     

黄曲霉毒素B1时间分辨荧光定量检测体系适用性评价

目的评价黄曲霉毒素B_1时间分辨荧光定量检测体系(包括黄曲霉毒素B_1时间分辨荧光免疫层析检测卡和荧光定量检测仪)的适用性。方法用时间分辨荧光定量检测体系测定20个阴性样本中黄曲霉毒素B_1的含量,确定该检测体系的检出限(limit of detection,LOD)和定量限(limit of quantification,LOQ);用2台荧光检测仪对6组含不同浓度黄曲霉毒素B_1的大米和玉米阳性样本进行检测,确定方法的准确性和台间差;重复6次检测含中等浓度黄曲霉毒素B_1的阳性样本和连续12 h检测国标检测限浓度的阳性标准溶液,确定方法的重复性和稳定性。结果该检测体系的LOD和LOQ分别为0.7和2.1μg/kg;该检测体系的检测值与大型仪器定值结果无显著性差异,2台荧光检测仪的测值之间无显著性差异;中浓度阳性样本和连续12 h测定检测限浓度的标准溶液的标准偏差未超过国家标准规定要求,检测结果的稳定性和重复性满足国家标准要求。结论该时间分辩荧光定量检测体系能够准确检测玉米和大米样本中黄曲霉毒素B_1含量。     

我国国家标准和行业标准中黄曲霉毒素测定方法综述

黄曲霉毒素广泛存在于自然界中,能够污染多种农作物和食品,对人类的健康造成极其严重的危害。目前,尚无绝对有效的措施避免黄曲霉毒素的污染,因此,制定相应的标准并进一步规范和加强对黄曲霉毒素的检测和监控显得尤为重要。截至到2015年1月,我国现行的针对黄曲霉毒素的国家标准和行业标准共有21个,其中有11个标准在2010~2015年发布实施。本文全面综述了21个标准中采纳的7种测定方法及其特点,其中高效液相色谱法是目前广泛使用的最权威的确证定量测定方法,而免疫层析法则是最简便的快速筛查定性检测方法。在此基础上,本文进一步讨论了标准的制修订现状,并展望了黄曲霉毒素检测技术的发展趋势。     

河北省玉米贮藏期黄曲霉毒素B1污染调查及安全性评价

为了调查河北省玉米黄曲霉毒素的污染情况,并对玉米的安全性做出初步评价,从河北省不同玉米产地采集贮藏期的玉米样品92个,采用ELISA酶联免疫检测技术对玉米样品进行黄曲霉毒素B_1检测并根据国家标准进行安全性评价。结果显示,黄曲霉毒素B_1检出率为84.8%,根据食品和饲料中黄曲霉毒素B_1的限量标准,符合食用标准的玉米占87.0%,符合饲用标准的占95.7%。冀中南生产区域玉米黄曲霉毒素B_1污染普遍,但整体污染程度较低。对于黄曲霉毒素污染超标玉米,应加强其安全性跟踪监控工作。     

玉米霉变及黄曲霉毒素的图像处理检测方法

为准确快速识别出仓储玉米是否包含霉变以及感染黄曲霉毒素的玉米颗粒,提出基于图像处理技术的定性、定量检测方法。基于感染霉菌的玉米颗粒表层会发生颜色褐变、发黑等特点,通过MATLAB对灰度图像二值化、区域填充、去干扰、连续膨胀等操作,统计出霉变颗粒数目;同时,基于感染黄曲霉毒素的玉米颗粒在365 nm紫外光照射下会发出独特的黄绿色荧光(bright greenish-yellow fluorescence,BGYF)特性,通过对彩色图像进行增强、形态滤波、彩图二值化、去除干扰、图像连续膨胀等,统计出感染黄曲霉毒素玉米颗粒的数量。用4组共112粒玉米对所提方法进行检测验证的结果表明,霉变玉米颗粒的正确检出率达93.75%以上,感染黄曲霉毒素玉米颗粒的正确检出率亦可达87.5%以上,能够达到区分检测的要求。     

光化学衍生法结合HPLC测定食品和饲料中的黄曲霉毒素

黄曲霉毒素的急性毒性很强，是重要的致癌物质。本文采用光化学衍生法结合HPLC测定了食品和饲料中的黄曲霉毒素，研究了光化学衍生的效果。结果表明，经光化学柱后衍生，四种黄曲霉毒素的检测灵敏度都比较高，检出限可达到3．25pg。     

Validation of a confirmatory analytical method for the determination of aflatoxins B₁, B₂, G₁ and G₂ in foods and feed materials by HPLC with on-line photochemical derivatization and fluorescence detection

A sensitive and selective analytical method for the simultaneous separation and quantitative determination of aflatoxins B1, B2, G1 and G2 in foodstuffs and materials for feed has been validated. The method is based on high performance liquid chromatography with on-line post-column photochemical derivatization and fluorescence detection. The chromatographic separation of aflatoxins was accomplished using a C18 column eluted with an isocratic mobile phase consisting of water, methanol and acetonitrile. The sample preparation required a simple extraction of aflatoxins with MeOH/H2O (80:20, v/v) and a purification step by immunoaffinity column cleanup. The total analysis time, including sample preparation and chromatographic separation, did not exceed 40 min with a run time of 10 min. The on-line photochemical derivatization ensures better results in terms of simplicity, sensitivity and reproducibility with respect to chemical derivatization techniques, and provides an increase of the peak resolution and an extent of automation in comparison with the electrochemical ones. The procedure for the determination of aflatoxins in food samples and cereals for animal consumption was extensively validated following Regulation (EC) No. 882/2004. Detection limits in wheat bran samples of 0.08 μg kg1 for AFB1, 0.02 μg kg1 for AFB2, 0.16 μg kg1 for AFG1 and 0.04 μg kg1 for AFG2 were attained. The method allows high recovery with mean values ranging from 72 to 94% and it satisfies the necessary requirements for sensitivity, linearity, selectivity, precision and ruggedness, demonstrating the conformity of the method with provisions of Regulation (EC) No. 401/2006.     

Aflatoxins in Foods and Feedstuffs. Part 1. The Fluorescence Micro-method of Aflatoxin Determination in solution

The fluorescence micromethod of aflatoxins B₁, B₂, G₁ and G₂ determination in solution is described. The amount about 0.1 μg of aflatoxins B₁ and G₁, and 0,01 μg of aflatoxins B₂ and G₂ in one spot after elution with methanol can be determined, with accuracy about 5%. The results of described fluorescence method are in agreement with results of spectrophotometric, fluorodensitometric and visual determinations. A very strong influence of light on results of aflatoxins B₁ and G₁ determination was stated. Photodecomposition of aflatoxins B₁ and G₁ to several photoproducts was observed.     

Validation of a confirmatory analytical method for the determination of aflatoxins B1, B2, G1 and G2 in foods and feed materials by HPLC with on-line photochemical derivatization and fluorescence detection

A sensitive and selective analytical method for the simultaneous separation and quantitative determination of aflatoxins B₁, B₂, G₁ and G₂ in foodstuffs and materials for feed has been validated. The method is based on high performance liquid chromatography with on-line post-column photochemical derivatization and fluorescence detection. The chromatographic separation of aflatoxins was accomplished using a C₁₈ column eluted with an isocratic mobile phase consisting of water, methanol and acetonitrile. The sample preparation required a simple extraction of aflatoxins with MeOH/H₂O (80:20, v/v) and a purification step by immunoaffinity column cleanup. The total analysis time, including sample preparation and chromatographic separation, did not exceed 40 min with a run time of 10 min. The on-line photochemical derivatization ensures better results in terms of simplicity, sensitivity and reproducibility with respect to chemical derivatization techniques, and provides an increase of the peak resolution and an extent of automation in comparison with the electrochemical ones. The procedure for the determination of aflatoxins in food samples and cereals for animal consumption was extensively validated following Regulation (EC) No. 882/2004. Detection limits in wheat bran samples of 0.08 µg kg^?1 for AFB₁, 0.02 µg kg^?1 for AFB₂, 0.16 µg kg^?1 for AFG₁ and 0.04 µg kg^?1 for AFG₂ were attained. The method allows high recovery with mean values ranging from 72 to 94% and it satisfies the necessary requirements for sensitivity, linearity, selectivity, precision and ruggedness, demonstrating the conformity of the method with provisions of Regulation (EC) No. 401/2006.     

Fluorescence and Aflatoxin Content of Individual Almond Kernels Naturally Contaminated with Aflatoxin

An effort was made to relate the aflatoxin content of individual almond kernels to their fluorescent color. The fluorescence of individual blanched almonds and defective almonds, most of which lack an intact pellicle, was described by means of Methuen color charts before each kernel was analyzed for aflatoxin. Almonds that fluoresced violet-purple under long-wave UV light were found to contain high levels of aflatoxins B₁ and B₂ but, with perhaps one exception, no measurable amounts of aflatoxins G₁ and G₂. Some diced almonds with blue fluorescence had all four aflatoxins present but at much lower levels than in the violet-purple kernels. Aflatoxin ranged from 1.0 × 10⁵ to 2.5 × 10⁶ ppb in the violet-purple kernels. These values agree with previous estimates of aflatoxin concentration per contaminated nut. Almond kernels with violet-purple fluorescence should be culled.     

Fluorescence changes of aflatoxins B1 and G1.

The effects of various factors, such as pH, buffer, sodiumchloride and ultra-violet radiation on the fluorescence of aflatoxins B1 and G1 have been studied. The fluorescence characteristics of aflatoxins B1 and G1 underwent a marked change at pH values above 7.2. Prolonged exposure to ultra-violet radiation lead to some degradation of aflatoxins and the extent of degradation was dependent upon the nature of the solvent. Sodium chloride partially protected the toxins from degradation by ultra-violet radiation or alkaline conditions.     

Aflatoxins contamination in spices and processed spice products commercialized in Korea

A survey for total aflatoxins (aflatoxins B₁, B₂, G₁, and G₂) was conducted on 88 spices and processed spice products commercialized in Korea. The presence of aflatoxins was determined by high-performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. Total aflatoxins (AFs) are detected in 12 samples (13.6% of incidence) including seven red pepper powder, two red pepper pastes (Kochujang), two curry and one ginger product. The contamination levels are 0.08–4.45 μg/kg as aflatoxin B₁ and 0.08–4.66 μg/kg as AFs. The liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis on contaminated samples was conducted for the confirmation of detected aflatoxins. The 12 samples which showed aflatoxins by HPLC/FLD were confirmed as aflatoxins by LC–MS/MS.     

现行黄曲霉毒素液相色谱检测法的比较与评价

目的 综合评价检测黄曲霉毒素的几种现行液相色谱-荧光法。方法 采用均质(涡旋)、超声辅助液液萃取技术对样品中的黄曲霉毒素进行提取, 免疫亲和柱和多功能柱净化。并采用不同的检测技术[三氟乙酸(TFA)柱前衍生法、光化学柱后衍生法、碘和溴柱后衍生法、大体积流动池直接检测及光化学柱后衍生串联大体积流动池]对玉米质控样品中黄曲霉毒素进行了分析。结果 各方法的检测结果均较理想, 可满足常规样品的检测要求。结论 超高压液相色谱-大体积流动池检测法在有效提高工作效率的同时, 大量减少了有毒有害试剂的使用量, 且具有最高的检测灵敏度, 可满足GB 2761-2011中对各类样品中黄曲霉毒素的限量要求。采用乙腈-水或甲醇-水体系均能达到较好提取黄曲霉毒素的目的。免疫亲和柱的净化效果较多功能柱好。     

黄曲霉毒素的生物合成、代谢和毒性研究进展

食品中黄曲霉毒素污染是最近关注的热点,这些毒素侵染农产品会带来很大经济损失。黄曲霉毒素有非常高的肝毒性、肝致肿瘤性、致畸和致突变性,可在采前、采中和采后的各种环境下侵染多种重要农产品,例如花生、玉米、水稻和棉籽。自然界中黄曲霉毒素的产生取决于多种因素,例如碳、氮、温度、水分活度、pH值、发育阶段、氧化胁迫、植物代谢产物。黄曲霉毒素可引起多种疾病,但是可以通过阻断和干扰吸收及干扰代谢酶来调节体内的黄曲霉毒素。本文概述黄曲霉毒素的生物合成、侵染、运输、代谢和毒性。研究它的生物合成、毒性机制、结构与功能关系和代谢运输途径,为制定有效控制黄曲霉毒素的措施提供更加深入的见解。     

黄曲霉毒素新型抗体制备研究进展

免疫学检测方法具有快捷、灵敏、特异性高的特点,在毒素的定量和定性方面已获得了快速的发展,成为毒素检测方法的研究热点。而高质量抗体的制备是建立特异性强、灵敏度高的免疫分析方法关键。目前主流研究和应用的抗体是单克隆抗体,其性质稳定,特异性强,灵敏度高。随着抗体技术的发展,重组抗体在免疫检测领域也逐渐应用。与多克隆抗体、单克隆抗体相比较而言,重组抗体具有独特的优势,可以在原核表达体系里短时间内大量生产且生产费用低廉,对黄曲霉毒素的低成本、大规模检测有重要的应用价值。本文重点阐述和分析了黄曲霉毒素单克隆抗体、重组抗体制备过程中存在的影响因素及问题,并对未来黄曲霉毒素抗体的发展前景进行了展望。