基质固相分散-高效液相色谱法测定袋泡茶中黄曲霉毒素

提出了基质固相分散-高效液相色谱法测定袋泡茶中黄曲霉毒素B1、B2、G1和G2含量的方法。优化的试验条件为:1样品与分散剂(中性氧化铝)的质量比为1比4;2洗脱剂乙腈的用量为6mL。以Symmetry C18色谱柱为分离柱,以甲醇-水(1+1)混合液为流动相进行分离。采用荧光检测,激发波长为365nm,发射波长为435nm。黄曲霉毒素B1、B2、G1和G2在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.05~0.15μg·L-1之间,测定下限(10S/N)在0.15~0.50μg·L-1之间。以空白样品为基体进行加标回收试验,所得回收率在88.3%~96.8%之间,测定值的相对标准偏差(n=6)在4.3%~6.8%之间。     

高效液相色谱-三重四极杆串联质谱测定谷物中T-2毒素和HT-2毒素

建立了快速分析谷物样品中T-2毒素和HT-2毒素的高效液相色谱-三重四极杆串联质谱( HPLC-MS/MS)分析方法.样品经乙腈-水(80:20,V/V)混合溶剂提取,免疫亲和柱净化后,采用HPLC-MS/MS测定.T-2毒素和HT-2毒素的检测线性范围均为0.20 ～20.00 μg/kg,定量下限为0.20 μg/...     

固相萃取-高效液相色谱柱后衍生荧光检测花生中黄曲霉毒素B1,B2,G1和G2

测定黄曲霉毒素主要有薄层色谱法、往前衍生液相色谱法和柱后衍生液相色谱法等。样品净化主要有液．液分配、C18键合柱、免疫亲和柱等方法。OASIS^R HLB是Waters公司近几年开发的亲水亲酯固相萃取柱,已用于腐败生物组织中吗啡的检测,它与传统的C18柱相比具有选择范围广、吸附能力强、重现性好、回收率高等特点,但尚未见应用于花生中黄曲霉毒素测定的报道。本文采用OASIS^R HLB固相小柱,建立了以碘作为柱后衍生试剂,反相液相色谱荧光检测花生中黄曲霉毒素B1,B2,G1,G2的分析方法、该法简单,快速,分离能力强,基体干扰少,准确度高。     

高效液相色谱-串联质谱法测定山茶油中黄曲霉毒素B1

建立了山茶油中黄曲霉毒素B1含量的高效液相色谱-串联质谱分析方法。通过对前处理方法的优化,选择了甲醇和水作为山茶油中黄曲霉毒素B1的提取溶剂,经免疫亲和柱富集浓缩后,采用高效液相色谱-串联质谱进行分析,经C18色谱柱分离,在电喷雾离子化正离子模式(ESI+)及多反应监测模式(MRM)下进行测定,基质匹配标准溶液外标法定量。在优化条件下,该方法线性范围为0.4～6.4μg/L,相关系数r2>0.998,最低检出限为0.026μg/kg,在添加水平为0.008,0.016和0.032μg时,方法回收率在85.9%～93.8%之间;相对标准偏差为1.8%～5.0%。方法可满足山茶油中黄曲霉毒素B1的检测要求。     

反相高效液相色谱-化学发光法测定复合维生素片剂中的维生素B1和B2

基于水溶性维生素在碱性介质中只有维生素B1(VB1)和维生素B2(VB2)可以被K3Fe(CN)6直接氧化产生化学发光的原理,建立了反相高效液相色谱(RP-HPLC)分离柱后化学发光检测VB1和VB2的新方法,并成功应用于复合维生素B片剂中VB1和VB2的测定。该方法测定VB1,VB2的线性范围分别为1.0×10-3～1.0 g/L和1.0×10-3～0.1 g/L,检出限分别为2×10-4 g/L和8×10-4 g/L。对1.0×10-2 g/L VB1,VB2溶液连续11次测定的相对标准偏差     

高效液相色谱法测定功能性红曲米粉中的青霉素G钠

采用高效液相色谱法测定了功能性红曲米粉中的青霉素G钠,选用Aichrom Bond-AQ C18(250 mm×4.6 mm i.d.,5μm)色谱柱,V(甲醇)∶V(水)=30∶70为流动相,检测波长为215 nm,流速1 mL/min,结果青霉素G钠在1.0~500 mg/L范围内具有良好的线性关系,r=0.9999;回收率为99.0%~107.5%;检出限为0.2 ng。     

SPE-HPLC法测定枸杞中阿维菌素B1a残留量

建立了固相萃取前处理净化技术-高效液相色谱(HPLC)法检测枸杞中阿维菌素B1a残留量的方法.样品用乙腈提取,经C18固相萃取柱净化,采用C18柱(250 mm×4.6 mm i.d.,5 μm)分离,以V(甲醇):V(水)=85:15为流动相,在245 nm下进行检测.阿维菌素B1a在0.20～2.00 μg/mL范围呈良好的线性关系(γ=0.9994);该方法检出限(S/N=3)为0.02mg/kg;添加回收率为88.3%～102.5%,相对标准偏差为2.1%～3.8%.     

高效液相色谱-串联质谱法检测花生中的黄曲霉毒素B_1

应用高效液相色谱-电喷雾串联四极杆质谱联用系统(HPLC-MS/MS),在多反应离子检测方式(MRM)下,对花生中的黄曲霉毒素B1进行检测.对花生中黄曲霉毒素B1的提取、净化、液相分离及串联质谱等相关检测参数进行了优化研究.用V(甲醇):V(水)=6:4提取,OASIS HLB SPE小柱净化,定容过滤.采用V(甲醇):V(水)(含体积分数0.1%甲酸)=7:3为流动相,前级离子313.0,二级离子241.1、269.1,ESI正离子方式检测,在3.3 min出峰.结果表明,在ESI正离子模式下,黄曲霉毒素B1在其线性定量范围0.1～50μg/kg内,相关系数达到0.9999,检出限为0.03μg/kg,最低定量限为0.1μg/kg.低、中、高浓度添加回收率范围为93%～105%.     

G3(QCI)模型化学方法

建立了非微扰外推模式下的几种G3(QCI)方法：G3(QCI/fu1)、G3(QCI/fu2)、G3(QCI/ful)//B3PW91和G3(QCI/fu2)//B3PW91.其中,电子能量用QCISD(T,FC)/G3large直接计算,芯电子相关能分别在MP2/6-31G(d)和MP2/6-31G(d,p)级别上计算,对125个G2-1 test set 的计算结果表明,总体精度与G3和G3 //B3LYP相当;平均绝对偏差分别为4.370、4.389、4.061和4.022kJ mol-1,相应G3和G3//B3LYP分别为4.27和4.05kJ mol-1.文章提出的方法排除了G3中外推办法的不确定因素,且更适用于非平衡几何构型体系能量的定量计算。     

高效薄层色谱法测定黄曲霉毒素B1、B2、G1、G2

1引言本文建立了以多功能净化拄（MFC）净化,结合高效薄层色谱法测定食品中黄曲霉毒素B1、B2、G1、G2的方法,与经典薄层色谱法相比,样品前处理过程简单快速,且净化效果良好;改变了传统的双向展开方式,以单相展开即可达到分离检测的目的,大大提高了检测速度和效率。本方法用于花生样品的检测,取得良好的效果。2实验部分2．1试剂与仪器水为重蒸去离子水;甲醇,乙腈,苯均为分析纯;黄曲霉毒素标准储备液：黄曲霉毒素（美国SIGMA公司,纯度≥99％）B1＋B2＋G1＋G2各1．0mg/L,溶于苯＋乙腈（98＋2,V/V）;黄曲霉毒素标准溶液…     

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%.     

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.     

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.     

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).     

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.     

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.