胶体金免疫层析法快速检测赭曲霉毒素A在谷物及饲料中的研究

正应用胶体金免疫层析技术,建立一种快速检测谷物和饲料中赭曲霉毒素A的方法,其中包括胶体金的制备、金标抗体的制备、试纸条的组装和测试等步骤。测试结果表明赭曲霉毒素A快速检测试纸条对谷物类样品检测限为5 ng/m L,对饲料样品检测限为100ng/m L,检测时间为10 min,试纸条特异性好,假阳性率小于5%,假阴性率为0。该法使用简单方便,非常适合现场快速检测谷物和饲料中的赭曲霉毒     

胶体金免疫层析法快速检测赭曲霉毒素A研究

该研究应用胶体金免疫层析技术建立一种快速检测食品和饲料中赭曲霉毒素A方法。采用柠檬酸三钠还原法制备胶体金溶液,标记抗赭曲霉毒素A单克隆抗体,标记胶体金抗体喷涂于玻璃纤维上,赭曲霉毒素A偶联抗原OTA-OVA和二抗兔抗鼠IgG分别喷涂于硝酸纤维膜上作为检测限和质控线,依次将样品垫、胶体金垫、硝酸纤维膜和吸水纸组装成试纸条并装卡。测试结果表明,赭曲霉毒素A快速检测试纸条灵敏度为5 ng/mL,检测时间为10 min,批内和批间重复性为100%,假阳性率和假阴性率均为0。该法简单方便,非常适于现场快速检测赭曲霉毒素A。     

应用胶体金试纸条快速检测赭曲霉毒素A的研究

本文介绍了一种快速检测赭曲霉毒素A的胶体金试纸条的研制方法，其中包括胶体金的生产、金标抗体的制备、试纸条的组装和测试等步骤。测试结果表明赭曲霉毒素A快速检测试纸条的检测限为10ng／ml，检测时间为10min，加上使用方便，经济适用，使之适合于赭曲霉毒素A现场快速检测之用。     

酶联免疫法检测乳制品及谷物中赭曲霉毒素A

研究采用酶联免疫技术检测谷物及添加谷物的牛奶中赭曲霉毒素A的含量特异性抗体(鼠抗单克隆赭曲霉毒素A抗体),赭曲霉毒素A标记的酶结合物和赭曲霉毒素A标准品或样品加入到微孔后,特异性抗体被牢固地结合在板条上的羊抗兔抗体IgG上,与此同时,游离的赭曲霉毒素A(在标准溶液或样品中)和酶结合物与特异性抗体竞争性结合.孵育后,在洗涤步骤中除去非结合(酶标记)试剂.加入色原底物(四甲基联苯胺),结合的酶结合物可将无色的色原转化成为有色的产物.加入硫酸,终止底物反应,在450nm波长检测吸光度值.本方法为快速检测方法,必要时,需用国家标准中规定的仲裁方法进行验证.     

赭曲霉毒素A无毒体系胶体金试纸条的研制及与传统胶体金试纸条的比较

本实验介绍了赭曲霉毒素A无毒体系胶体金试纸条的研制方法,其中包括胶体金的生产、金标抗体的制备、无毒体系试纸条的组装等步骤。所制备的赭曲霉毒素A无毒体系胶体金试纸条和传统的胶体金试纸条进行了比较,测试结果表明,赭曲霉毒素A无毒体系胶体金试纸条的检测限和检测时间与传统的胶体金试纸条相同,适合于赭曲霉毒素A现场筛查之用。     

同时检测玉米中黄曲霉毒素B1和赭曲霉毒素A的时间分辨荧光免疫层析试纸条的研制

研究制备了一种可同时快速定量检测黄曲霉毒素B1 (aflatoxin B1,AFB1)和赭曲霉毒素A(ochratoxin A,OTA)的二联时间分辨荧光免疫层析试纸条.采用铕系时间分辨荧光微球分别标记AFB1和OTA单克隆抗体,优化荧光微球活化pH值、标记的抗体浓度、荧光探针使用量、检测线包被原浓度、质控线羊抗鼠Ig...     

赭曲霉毒素A时间分辩荧光定量检测体系适用性评价

目的验证赭曲霉毒素A(ochratoxin A,OTA)时间分辨荧光免疫定量检测体系对谷物中赭曲霉毒素A快速检测的适用性。方法该时间分辨荧光免疫定量检测体系包括时间分辨荧光免疫层析检测卡和时间分辩荧光定量检测仪。时间分辨荧光速测仪内置标准曲线,直接得出待测样品中赭曲霉毒素A的含量。对待测样品进行低、中、高3个浓度添加,每个浓度分为7份,由不同人员检测。同时,对实际阳性样品进行检测。结果对谷物做赭曲霉毒素A添加回收率实验,回收率在98%~113%之间;批内变异系数15%。在实际样品的检测中,时间分辨荧光定量检测卡得出的数值,与质控样本标识的值没有显著性差异。结论时间分辨荧光定量检测系统检测快速、准确,稳定、检测设备小型化、联网可实现数据上传,适用于大批量谷物样品的快速检测和风险评估。     

苯乙醇胺A荧光免疫层析试纸条的制备及特性

为通过荧光免疫层析技术制备一种快速、灵敏、特异性强的尿液中苯乙醇胺A（phenylethanolamine A,PEAA）的检测方法,采用重氮化法合成PEAA人工抗原,并通过免疫、融合、有限稀释法获得特异性抗PEAA的单克隆抗体,通过将量子点微球与PEAA偶联,制备荧光免疫层析试纸条。结果表明：PEAA免疫荧光层析试纸条的检测限为0.496 μg/L,回收率在80%～120%之间,批内、批间变异系数均小于10%,与其他类似物的交叉反应率小于5%,特异性良好。说明将荧光免疫层析技术应用到PEAA检测中是可行的,且制备的PEAA荧光免疫层析试纸条灵敏度高、准确性好、特异性好,应用前景广阔。     

农产品中赭曲霉毒素A免疫层析试纸条快速检测技术研究

基于胶体金免疫层析原理建立了一种快速检测赭曲霉毒素Ａ（ｏｃｈｒｏｔａｘｉｎＡ,ＯＴＡ）的胶体金试纸条的研制方法,包括胶体金的制备、金标记探针的制备、试纸条各条件参数的测试和优化等。试纸条检测ＯＴＡ的肉眼可视检测限为０．２５ｎｇ／ｍＬ,检测时间为１０ｍｉｎ,试纸条能特异性识别ＯＴＡ而不与赭曲霉毒素Ｂ及其他真菌毒素发生交叉反应,使用简单、方便、成本低,重复性好,保质期长,尤其适用于农产品中ＯＴＡ的现场快速筛查。     

抗赭曲霉毒素A多克隆抗体的制备

为了制备赭曲霉毒素A多克隆抗体,采用戊二醛法合成赭曲霉毒素A-BSA人工抗原,通过紫外扫描法鉴定半抗原与载体蛋白偶联效果.合成的人工抗原用弗氏佐剂乳化后免疫Balb/c小白鼠,4次免疫后眼球下缘采血,分离血清.试验结果表明,免疫后产生了抗赭曲霉毒素A-BSA的特异性多克隆抗体,抗体效价为1:8100,赭曲霉毒素A的最低...     

Study on ochratoxin A in cereal-derived products from Spain

A study on ochratoxin A (OTA) in cereal-derived products was carried out. Cereal-based baby foods, breakfast cereals and beers were analyzed for mycotoxin OTA using an in-house developed high-performance liquid-chromatographic method.OTA was detected in 19 of the 21 samples of breakfast cereals (limit of detection 0.066 μg/kg), in 14 of the 20 samples of cereal-based baby foods (limit of detection 0.035 μg/kg) and in 24 of the 31 samples of beer (limit of detection 0.012 μg/l). The mean concentrations of OTA found were the following: 0.265 μg/kg in breakfast cereals, 0.187 μg/kg in cereal-based baby food and 0.044 μg/l in beer. The influence of different factors, such as the fibre content in breakfast cereals, type of cereals used in cereal-based baby food and alcohol content in beer, on the OTA levels was studied.     

量子点标记免疫层析试纸条快速检测莱克多巴胺的研究

本实验通过莱克多巴胺抗原抗体的制备、量子点的制备、试纸条的组装和测试等步骤研究一种将量子点应用于莱克多巴胺免疫层析试纸条的新方法。结果表明,莱克多巴胺快速检测试纸条的检测限为3ng/ml,检测时间为10min。本法使用方便、经济,适合于莱克多巴胺现场快速检测。     

4 种硝基呋喃代谢物复合荧光免疫层析试纸条的制备

为建立一种基于量子点荧光免疫层析技术快速检测4 种硝基呋喃类代谢物的方法,采用N-羟基琥珀酰亚胺（N-hydroxysuccinimide,NHS）、1-乙基-3-（3-二甲氨基丙基）碳二亚胺盐酸盐（1-ethyl-3-（3-dimethylaminopropyl）carbodiimide hydrochloride,EDC）法合成4 种硝基呋喃类代谢物的人工抗原,并融合制备对应的单克隆抗体,通过EDC-NHS一步法将量子点微球（quantum dot submicrobeads,QBs）分别与3-氨基-2-恶唑烷酮（3-amino-2-oxazolidinone,AOZ）、5-甲基吗啉-3-氨基-2-唑烷基酮（5-morpholine-methyl-3-amino-2-oxazolidinone,AMOZ）、1-氨基-2-乙内酰（1-aminohydantoin,AHD）和氨基脲（semicarbazid,SEM）偶联,得到相应的QBs探针,在此基础上制备复合荧光免疫层析试纸条。结果表明：AOZ、AHD、SEM和AMOZ的检出限分别为0.4、0.4、0.5、0.5 μg/L;通过加标回收实验对批内和批间的重复性和准确度进行评价,得出该试纸条的批内检测回收率为80%～110%,批内变异系数在15%以内,批间回收率为80%～100%,批间变异系数在15%以内;且AOZ、AHD、SEM和AMOZ之间的交叉反应率小于0.1%,说明成功将荧光免疫层析技术和多元检测技术相结合,应用于同时检测4 种硝基呋喃类代谢物,且试纸条的灵敏度和准确性高、特异性好。     

高灵敏度磁荧光免疫层析试纸模式构建及在呕吐毒素检测中的应用

构建基于磁荧光纳米材料的免疫层析试纸模式,弥补现在免疫层析技术的不足,为更灵敏的免疫学快速检测提供技术支撑。以呕吐毒素（deoxynivalenol,DON）为靶标,采用溶剂热法制备羧基修饰的超顺磁颗粒,碳二亚胺法将磁颗粒、绿色荧光蛋白及DON单克隆抗体进行偶联,一步法制备磁荧光抗体探针,以DON人工抗原（DON-BSA）为检测线建立磁荧光免疫层析试纸。同时用胶体金标记DON单克隆抗体,以DON-BSA为检测线建立胶体金免疫层析试纸;制备的磁荧光抗体探针具有很好的磁性、荧光特性及抗体反应性,基于该探针成功制备了DON磁荧光免疫层析试纸,该试纸回归方程为y=－0.562x＋0.921,R2=0.990,IC50为5.611 ng/mL,检出限为1.089 ng/mL;制备了DON胶体金免疫层析试纸,该试纸裸眼检测灵敏度为500 ng/mL;定量检测回归方程为y=－0.543x＋1.485,R2=0.991,IC50为65.16 ng/mL,检出限为11.94 ng/mL。DON磁荧光免疫层析试纸的灵敏度是胶体金免疫层析试纸的10.96 倍。本实验建立的磁荧光免疫层析试纸模式可以同时实现样品的富集及荧光信号检测,提高检测灵敏度,并成功用于DON的检测,为磁荧光纳米颗粒广泛应用于免疫层析领域提供参考。     

Rapid on‐site determination of melamine in raw milk by an immunochromatographic strip

A rapid and simple method was established based on gold nanoparticle‐labelled monoclonal antibody probes for the detection of melamine pollution in raw milk. The conditions for conjugation between the antibody and gold nanoparticles were optimised (pH 8.0, antibody concentration 5 μg mL^?1). It gives a single proportional to melamine concentration with a performance time of only 3 min. A practical calibration curve was established with a reader system with limit of detection calculated as 4.47 and 8.34 μg L^?1 with naked eyes. Three structural analogues, atrazine, desethyl‐desisopropyl‐atrazine and cyromazine, were used to test the specificity of the immunochromatographic strip, and small colour changes on the strip test line were found even at the 500 ng mL^?1 spiked level. Fifty raw milk samples were detected with this strip method, and the resulting data coincided well with results from gas chromatography tandem mass spectrometry. The above‐mentioned results showed that this test strip can be used for melamine screening in the daily monitoring of milk.     

The method of the simultaneous determination of the citrinin and ochratoxin A content in cereals and cereal products

The simplifyed method of simultaneous determination of the citrinin (CT) and ochratoxin A (OTA) in cereals is described. The extraction of mycotoxins was carried out by small volumes of solvents (water/aceton/hexane) without additional sample clean up and concentration. The extracts were analysed by HPLC using mixture of methanol/ethylacetate/phosphoric acid, pH 2.2 as a mobile phase and fluorescence detection (lamda ex 330 nm, lamda em 495 nm). The reliability and reproducibility of results were improved by usage of internal standard--methyl-derivative of ochratoxin A. Average recovery of CT and OTA was 70%, relative standard deviation 12% and 7%, respectively, limit of detection 0.003 mg/kg.     

Determination of Ochratoxin A in Cereals and Feeds by Ultra-performance Liquid Chromatography Coupled to Tandem Mass Spectrometry with Immunoaffinity Column Clean-up

This paper describes the preparation of reusable immunoaffinity columns and the development of an ultra-performance liquid chromatography tandem mass spectrometry method combined with immunoaffinity column clean-up (IAC-UPLC-MS/MS) for the determination of ochratoxin A (OTA) in cereals and feeds. The monoclonal antibody (mAb) was produced from a stable hybridoma cell line (4H10), which belongs to the immunoglobulin G1 (κ-light chain) isotype. A competitive indirect enzyme-linked immunosorbent assay was used to characterize the mAb. The concentrations causing 50 % inhibition of binding of mAb to OTA-ovalbumin by free OTA, ochratoxin B, and ochratoxin C were 1.29, 4.78, and 0.94 ng mL^?1, respectively. The IAC-UPLC-MS/MS method offers a limit of quantification (LOQ, S/N >10) ranging from 0.5 to 1.0 μg kg^?1 and a limit of detection (LOD, S/N >3) ranging from 0.2 to 0.3 μg kg^?1 in cereal and feed samples. The IAC-UPLC-MS/MS method offers a good LOQ and LOD for OTA in cereal and feed samples. The accuracy and precision at this level fall within the EU regulatory limit. This methodology has been validated in four different matrices (millet, maize, soybean, and swine finisher diet) with highly satisfactory results and applied to the analysis of samples collected from the markets.     

Development of a Nanobody-Based Competitive Dot ELISA for Visual Screening of Ochratoxin A in Cereals

A polyvinylidene fluoride membrane-based dot immunoassay using nanobody (Nb) for rapid, qualitative, and visual detection of ochratoxin A (OTA) in cereals was developed. On the basis of optimal assay conditions, the cut-off level of this method assessed visually was 5 μg/kg for OTA, and the final results were obtained within 20 min. This method was simple with no time-consuming cleanup procedure. Good accuracy and reproducibility were obtained in recovery experiments. Results of the Nb-based dot ELISA are in agreement with the ELISA kit, except for samples that were negative for OTA presence assessed through Nb-based dot ELISA but found positive through the ELISA kit. These results indicated that the developed method could be a useful on-site screening tool for rapid detection of OTA in cereals without special instrument.

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Graphic Abstract Flow chart of nanobody-based dot ELISA for OTA visual screening