高效液相色谱-质谱法测定花生中的植物螯合肽

以镉胁迫花生为原料,建立了液相色谱-电喷雾电离质谱联用仪测定花生中的植物螯合肽的LC-MS方法.以C18反相柱为分析柱,1%三氟乙酸、乙腈为梯度洗脱淋洗液,能够检测出花生中的植物螯合肽.在本实验条件下,检出限为0.2 mg/L;线性范围在0.50～20.0 mg/L(r≥0.9974);回收率大于80%.方法灵敏度高,实用性强.应用本方法对实际花生样品中的PC4进行了定量分析.初步证实了花生中存在丙氨酸类植物螯合肽.结果表明,受镉胁迫的花生中均检出不同浓度的PC4.     

气相色谱法同时测定花生中12种有机磷农药残留量

建立了气相色谱法同时测定花生中12种有机磷农药残留量的方法.花生中有机磷农药残留通过乙腈提取,经液-液分配后有机相浓缩以丙酮定容,应用氮磷检测器(NPD)检测.除敌百虫和杀扑磷的检测限分别为20、50 μg/kg以外,其余10种有机磷农药检测限均为10 μg/kg.加标回收率为68.70%～108.45%,测定结果的相对标准偏差为3.05%～19.10%(n=5).该法与单独测定这12种有机磷农药的加标回收率和相对标准偏差基本符合.     

酶联免疫吸附分析法检测花生过敏原的研究

本文利用自己研制的花生过敏原免疫新西兰大耳兔,获得效价为200 000的抗花生过敏原特异性抗体,建立了花生过敏原蛋白的间接竞争酶联免疫(ELISA)检测方法.结果表明:花生抗原在0.01～100 ng/mL范围内具有较好的线性关系,其竞争标准曲线为v=-0.1212x+0.9285(r=0.9819),IC50为34....     

固相萃取-气相色谱法同时测定花生中18种有机氯农药残留

利用气相色谱(GC)建立了花生中18种有机氯农药同时测定的方法。花生中有机氯农药残留通过乙腈提取,减压浓缩后过弗罗里固相萃取柱净化,采用正己烷-丙酮(体积比为9∶1)溶液淋洗,淋洗液氮吹近干后以正己烷定容,应用微池电子捕获检测器(μECD)检测。氟氯氰菊酯和溴氰菊酯的检出限分别为50和100g/kg,其余16种有机氯农药检出限均为10μg/kg。在花生样品中添加检测限水平有机氯混标溶液,加标回收率为71.28%～116.58%,测定结果的相对标准偏差为4.08%～18.16%(n=4或5)。     

气相色谱法测定花生中六六六、滴滴涕、乙草胺和毒死蜱残留

建立了毛细管柱气相色谱法同时测定花生中六六六、滴滴涕、乙草胺和毒死蜱的方法。样品用乙腈提取,固相萃取柱净化,气相色谱仪电子捕获检测器(ECD)进行测定。结果表明,10种农药含量在0.005~1.0 mg/L之间线性关系良好,相关系数均在0.995以上,加标回收率在80.5%~116.9%之间,相对标准偏差在1.2%~5.0%之间。方法适用于花生中六六六、滴滴涕、乙草胺和毒死蜱的同时测定。     

石墨炉原子吸收光谱法测定黑花生中痕量锗

建立了高压密闭消解-石墨炉原子吸收法测定黑花生中痕量锗的分析方法。优化了石墨炉原子吸收法的测定条件。该法以Pd(NO3)2+Ni(NO3)2为基体改进剂,样品的灰化温度和原子化温度分别为1100℃和2300℃,锗的检出限为3.27μg/L;回收率为92.7%～105.0%;相对标准偏差为1.74%～4.65%。研究结果表明:花生仁及其包衣中均含有痕量锗,且黑花生中锗含量高于同一产地出产的另外两个品种。     

自动QuEChERS结合气相色谱-串联质谱法测定花生中297种农药残留

建立了基于自动QuEChERS方法的花生中297种农药的气相色谱－串联质谱（GC－MS/MS）快速检测技术,并对提取剂种类及用量、缓冲盐用量、净化剂种类及用量进行了优化。花生样品加水浸润后,采用1%（体积分数）醋酸乙腈提取,结合自动QuEChERS前处理设备,以N-丙基乙二胺（PSA）、十八烷基硅烷键合硅胶（C18）、碳十八键合锆胶（Z－Sep+）和无水硫酸镁为填料进行净化。净化液经 1 mL 乙酸乙酯复溶后,过0. 22 μm 有机微孔滤膜,采用 GC－MS/MS 在多重反应监测（MRM）模式下进行测定,基质匹配外标法进行定量。结果表明,所有农药的相关系数（r2）均大于0. 995,定量下限为 2～10 μg/kg;在 10、20、50、100 μg/kg4 个加标水平下的平均回收率分别为 72. 7%～116%、71. 9%～117%、73. 2%～112% 和 71. 5%～120%,相对标准偏差（RSDs）分别为 0. 90%～15%、0. 70%～15%、0. 60%～14% 和 0. 40%～15%。应用所建立的方法对市售8批次花生样品进行检测,结果表明,8批次样品中共有6批次检出农药残留,共检出17种农药,其中一批样品中百治磷检出浓度最高,达到34. 67 μg/kg。该方法简便、快速、灵敏度高且自动化程度高,适用于花生中数百种农药多残留的快速检测分析。     

多功能针式过滤器净化超高效液相色谱法测定大米和花生中玉米赤霉烯酮

建立了一种基于多功能针式过滤器净化的超高效液相色谱测定大米和花生中玉米赤霉烯酮的方法。样品经乙腈提取,采用多功能针式过滤器通过式净化,以超高效液相色谱法测定其中的玉米赤霉烯酮,色谱柱为ACQUITY UPLC BEH C18柱（100 mm×2.1 mm,1.7μm）,以甲醇-乙腈-水（体积比为8∶46∶46）为流动相等度洗脱,流量为0.3 mL/min,用荧光检测器检测,色谱峰面积外标法定量。玉米赤霉烯酮的质量浓度在2.5～500 ng/mL范围内与色谱峰面积线性关系良好,相关系数不小于0.999 5。大米和花生样品的方法检出限分别为15.0、30.0μg/kg,定量限分别为50.0、100.0μg/kg。样品加标回收率为77.11%～93.65%,测定结果的相对标准偏差为0.49%～4.95%(n=6)。该方法简便快速,适用于大米和花生中玉米赤霉烯酮的日常检测。     

花生微波烘烤香气成分分析方法的建立与应用

建立了烤制花生香气成分分析的顶空固相微萃取/气相色谱-质谱(HS SPME/GC-MS)分析方法。优化的实验条件:HP-5色谱柱,萃取平衡温度80℃,萃取时间40 min,解析时间5 min。采用该方法对四粒红、大白沙、鲁花3种花生进行微波炉焙烤后产生的挥发性香气成分进行分析,共鉴定出29种成分,其中主要包括杂环类化合物9种,醛类化合物7种,醇类化合物3种,烯类化合物3种,酚类化合物2种,酯类化合物3种,其他化合物2种。根据上述风味物质对花生香味的贡献大小,选择7种主要特征香气成分2,5-二甲基吡嗪、2-乙基-3,5(6)-二甲基吡嗪、2-乙基-6-甲基吡嗪、2-戊基呋喃、2,3-二氢苯并呋喃、苯甲醛和苯乙醛进行定量分析,其标准曲线相关系数均超过0.997,标准物质的加标回收率为85%~101%,RSD不大于6.9%,检出限为0.63~13.4μg/L。比较了不同花生品种的香气差异,并通过分析不良风味成分苯乙醛的含量,发现以大白沙花生的特征香气浓度最高,苯乙醛含量最低,更适宜利用微波烘焙技术生产咸干花生食品。     

高效液相色谱法分离纯化微生物油脂中的花生四烯酸

为满足花生四烯酸样品制备的需要,将微生物油脂中制得的脂肪酸先经尿素包合(脲包法)和甲酯化后,再利用反相高效液相色谱法分离纯化其中的花生四烯酸。在C18反相柱上,以甲醇-水(体积比为95∶5)为流动相,采用示差折光检测器检测,流速为5 mL/min时,目标产物的分离度较佳。用气相色谱/质谱法(GC/MS)进行分析的结果表明,花生四烯酸甲酯在纯化后的样品中的质量分数由38%提高到99%以上,基本达到标准物质的质量要求。     

Overpressured layer chromatographic determination of aflatoxin B1, B2, G1 and G2 in red paprika

Determination of aflatoxin B1 and total aflatoxin (B1 + B2 + G1 + G2) in red paprika powder is described using column chromatographic sample clean-up, overpressured layer chromatography (OPLC) separation and fluorescence densitometric evaluation. Two OPLC methods were developed for separation of the four aflatoxins. The detection limit and quantification limit of aflatoxins in red paprika were 0.5 and 1 μg/kg in both methods, respectively. Recovery experiment was carried out with sample containing 1.74 μg/kg aflatoxin B1 and 3.56 μg/kg total aflatoxins measured by European standard HPLC method. Mean recovery amounted to 78.5% (SD 16.1%, n = 5) for aflatoxin B1 and 81.8% (SD 17.1%, n = 5) for total aflatoxins in the case of method 1. It was 105.3% (SD 10.7%, n = 5) for aflatoxin B1 and 97.4% (SD 18.6%, n = 5) for total aflatoxins using the method 2. Despite of that the Hungarian climate is not proper for the toxin production of moulds high aflatoxin B1 contaminated red paprika purchased from the market was found, which may originate from mixing of imported paprika containing very high level toxin with Hungarian one.     

Determination of aflatoxins B1, B2, G1 and G2 by high-performance liquid chromatography with electrochemical detection

A new approach to the determination of afiatoxins B₁, B₂, G₁ and G₂ is given; the method involves high-performance liquid chromatography with amperometric detection in the differential-pulse mode at the dropping mercury electrode with 1-s drop time. These aflatoxins can be determined simultaneously with good resolution but with some compromise in sensitivity. The detection limit of underivatized aflatoxin standards is around 5 ng. Average recoveries of aflatoxins from peanut butter by the Beebe method were G₂ 81%, G₁ 87%, B₂ 77% and B₁ 76%.     

Determination of aflatoxins B1, G1, B2 and G2 in medicinal herbs by liquid chromatography-tandem mass spectrometry

An easy method for the determination of aflatoxins B1, G1, B2 and G2 in Rhammus purshiana by LC coupled to mass spectrometry has been developed. Aflatoxins were extracted with a mixture of methanol and water and then it was purified by solid-phase clean-up using a polymeric sorbent, not described previously, for the determination of these toxins. The eluted extract was injected into the chromatographic system using a reversed-phase C18 short column with an isocratic mobile phase composed of methanol-water (30:70). A single-quadruple mass spectrometry using an electrospray ionization source operating in the positive ion mode was used to detect aflatoxins due to derivatization presenting several disadvantages. Recoveries of the full analytical procedure were 110% for aflatoxin B1, 89% for aflatoxin B2, 81% for aflatoxin G1 and 77% for aflatoxin G2. Detection limit (S/N = 3) was 10 ng and quantification limit (S/N = 10) was 25 ng, calculated as amount in medicinal herb.     

A Guide to Thin-Layer Chromatographic Systems for the Separation of Aflatoxin B1, B2, G1 and G2

Abstract

The separation of aflatoxin B₁, B₂, G₁ and G₂ was compared on six commercial silica gel plates in twelve solvent systems. Two of the solvent systems, chloroform: acetone: ammonium hydroxide (90: 10: 0.25) and chloroform: acetone: hexane (85: 15: 20) resolved the four aflatoxins on all the tested plates. The solvent modifier played an important role in the resolution of these compounds. The effect of the hardness of the plate is also discussed.     

固相萃取-高效液相色谱/串联质谱检测谷物中黄曲霉毒素B1、B2、G1、G2和M1

建立了高效液相色谱/串联质谱(LC-MS/MS)同时检测谷物中的黄曲霉毒素B1、B2、G1、G2和M1的方法.并优化了液相色谱条件和质谱的相关参数.谷物样品经研磨成粉末后,直接经甲醇-水( V∶V=10∶90)提取,Oasis HLB固相萃取净化,乙腈-水(0.2％甲酸)梯度洗脱,选择电喷雾离子源(ESI),正离子扫描...     

Large-scale purification of the mycotoxins aflatoxin B1, B2 and G1

The isolation and purification of gram quantities of the important mycotoxins aflatoxin B1, B2 and G1 are described. The method involves final purification on a Waters Prep LC-500 instrument, loaded with silica cartridges, and elution with chloroform.     

超高效液相色谱法快速测定发酵茶叶中的黄曲霉毒素

建立了用超高效液相色谱/紫外检测器测定发酵茶叶中黄曲霉毒素B1、B2、G1和G2的方法.用CH2Q2提取黄曲霉毒素,提取液经浓缩后,用LC-CN固相萃取小柱净化,超高效液相色谱测定.在浓度范围20～200μg/L(B1、G1),15～120μg/L(B2、G2)内具有良好的线性相关关系.黄曲霉毒素的回收率为81.4%～92.3%,相对标准偏差RSD 1.6%～4.2%.检出限为0.32μg/kg(B1、G1),0.18μg/kg(B2、G2)(S/N=3).     

Application of dispersive liquid-liquid microextraction for the determination of aflatoxins B1, B2, G1 and G2 in cereal products

The application of dispersive liquid-liquid microextraction (DLLME) technique for the rapid analysis of aflatoxins B(1), B(2), G(1) and G(2) in maize, rice and wheat products has been evaluated. After extraction of aflatoxins from cereal matrices with a mixture of methanol/water 8:2 (v/v), the analytes were rapidly transferred from the extract to another small volume of organic solvent, chloroform, by DLLME. Aflatoxins were determined using high performance liquid chromatography with florescence detection and photochemical post-column derivatization. Parameters affecting both extraction and DLLME procedures, such as extraction solvent, type and volume of DLLME extractant, volume of water and salt effect, were systematically investigated and optimized to achieve the best extraction efficiency. Under the optimal experimental conditions, the whole analytical method provides enrichment factors around 2.5 times and detection limits (0.01-0.17 μg kg(-1)) below the maximum levels imposed by current regulation for aflatoxins in cereals and cereal products intended for direct human consumption. Recoveries (67-92%) and repeatability (RSD<10, n=3), tested in three different cereal matrices, meet the performance criteria required by EC Regulation No. 401/2006 for the determination of the levels of mycotoxins in foodstuffs. The proposed method was successfully applied to the analysis of retail cereal products with quantitative results comparable to the immunoaffinity chromatography (IAC). The main advantages of developed method are the simplicity of operation, the rapidity to achieve a very high sample throughput and low cost.