Simultaneous identification and quantification of tetrodotoxin in fresh pufferfish and pufferfish-based products using immunoaffinity columns and liquid chromatography/quadrupole-linear ion trap mass spectrometry

In this study, we established a comprehensive method for simultaneous identification and quantification of tetrodotoxin （TTX） in fresh pufferfish tissues and pufferfish-based products using liquid chromatography/quadrupole-linear ion trap mass spectrometry （LC-QqLIT-MS）. TTX was extracted by 1% acetic acid-methanol, and most of the lipids were then removed by freezing lipid precipitation, followed by purification and concentration using immunoaffinity columns （IACs）. Matrix effects were substantially reduced due to the high specificity of the IACs, and thus, background interference was avoided. Quantitation analysis was therefore performed using an external calibration curve with standards prepared in mobile phase. The method was evaluated by fortifying samples at 1, 10, and 100 ng/g, respectively, and the recoveries ranged from 75.8%--107%, with a relative standard deviation of less than 15%. The TTX calibration curves were linear over the range of 1-1 000 ~tg/L, with a detection limit of 0.3 ng/g and a quantification limit of 1 ng/g. Using this method, samples can be further analyzed using an information- dependent acquisition （IDA） experiment, in the positive mode, from a single liquid chromatography-tandem mass spectrometry injection, which can provide an extra level of confirmation by matching the full product ion spectra acquired for a standard sample with those from an enhanced product ion （EPI） library. The scheduled multiple reaction monitoring method enabled TTX to be screened for, and TTX was positively identified using the IDA and EPI spectra. This method was successfully applied to analyze a total of 206 samples of fresh pufferfish tissues and pufferfish-based products. The results from this study show that the proposed method can be used to quantify and identify TTX in a single run with excellent sensitivity and reproducibility, and is suitable for the analysis of complex matrix pufferfish samples.

Improved Recovery of Erythropoietin and Darbepoetin from Equine Plasma by the Application of a Wheat Germ Agglutinin Mediated Pre-Extraction Prior to Immunoaffinity Chromatography

We describe a two-step method that uses wheat germ agglutinin immobilized on Sepharose gel followed by immunoaffinity chromatography (IAC) to extract recombinant human erythropoietin and Darbepoetin from equine plasma. Lectin affinity chromatography was shown to be an effective approach for isolating these epoetins from plasma and in combination with IAC;this method gave superior recovery when compared to the use of the latter technique alone. Moreover, due to the ease with which it can be scaled up, it is particularly well suited for pre-concentrating larger volumes of samples prior to IAC and this provides a facile way of improving the overall sensitivity with which these foreign proteins can be detected in equine plasma.

Preparation and Application of an Immunoaffinity Column for Direct Extraction of Morphine and its Analogs from Opium

A rapid, simple and accurate method using an immunoaffinity column (IAC) and capillary electrophoresis (CE) for the analysis of the major alkaloids in opium is developed. The IAC was synthesized by coupling specific morphine polyclonal antibodies to CNBr-actived Sepharose 4B. The IAC showed high selectivity and obvious enrichment to morphine, codeine, dionin and thebaine. The extraction solution was analyzed by CE with β-cyclodextrin as an additive. Recoveries of the four alkaloids from PBS were between 93%-105% with RSD value less than 5.0%. The result showed that this method was practical for the determination of morphine analogs in opium.

Clean-up and disposal process of polluted sediments from urban rivers

In this paper, the discussion is concentrated on the properties of the polluted sediments and the combination of clean-up and disposal process for the upper layer heavily polluted sediments with good flowability. Based on the systematic analyses of various clean-up processes, a suitable engineering process has been evaluated and recommended. The process has been applied to the river reclamation in Yangpu District of Shanghai City, China. An improved centrifuge is used for dewatering the dredged sludge, which plays an important role in the combination of clean-up and disposal process. The assessment of the engineering process shows its environmental and technical economy feasibility, which is much better than that of traditional dredging-disposal processes.

Bench-Scale Testing of Zinc Ferrite Sorbent for Hot Gas Clean-up

Advanced integrated gasification combined cycle （IGCC） power generation systems require the development of high-temperature, regenerable desulfurization sorbents, which are capable of removing hydrogen sulfide from coal gasifier gas to very low levels. In this paper, zinc ferrites prepared by co-precipitation were identified as a novel coal gas desulfurization sorbent at high temperature. Preparation of zinc ferrite and effects of binders on pore volume, strength and desulfurization efficiency of zinc ferrite desulfurizer were studied. Moreover, the behavior of zinc ferrite sorbent during desulfurization and regeneration under the temperature range of 350-400 ℃ are investigated. Effects of binders on the pore volume, mechanical strength and desulfurization efficiency of zinc ferrite sorbents indicated that the addition of kaolinite to zinc ferrite desulfurizer seems to be superior to other binders under the experimental conditions.

Simultaneous Determination of Four Estrogens in Compost Based on Ultrasonic Solvent Extraction, Solid-Phase Extraction Clean-Up and Analysis by UHPLC-MS/MS

A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost samples from the biodegradation of biological infectious hazardous wastes. Ultrasonic solvent extraction, using methanol as extraction solvent, coupled with SPE clean-up, using cartridges HLB 60 mg - 6 ml Supelco® and acetonitrile for reconstitution of eluents, was used for the simultaneous extraction of the four estrogens. Mean recoveries in the range of 98% - 107% were obtained. All compounds were separated in a single gradient run by UHPLC KinetexTM 2.6 μm XB-C18 100 ÅLC (50 × 4.6 mm) column. Analytes were detected via multiple reaction monitoring (MRM) using an AB SCIEX API-5000TM triple quadrupole (Applied Biosystems/MDS SCIEX) with electrospray ionization in negative mode. Isocratic mobile phase of Water:ACN (50:50) resulted to be the optimum. Limits of detection and quantification were on the order of 0.66 ng·g-1 and 2 ng·g-1 for all the estrogens. These limits were lower than most of the values reported in the literature for similar matrices. Suitable level of linearity, good repeatability and reproducibility with coefficients of variation is lower than 11.7%, 6.8% and 8.3%, respectively.

Effect of Matrix Clean-Up for Aflatoxin Analysis in Corn and Dried Distillers Grains

Aflatoxins are a group of highly carcinogenic mycotoxins that contaminate a wide variety of agricultural crops and have a detrimental economic impact on industries, such as corn and ethanol production. They are regulated by the FDA, and therefore, rapid, reliable cleanup techniques with low detection limits are needed for aflatoxins in a wide array of matrices. In this study the effect of using an immunoaffinity column versus simple filtering as a cleanup was tested for afltoxins extracted from corn and Dried Distillers Grains (DDG). The aflatoxins were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The use of an immunoaffinity column resulted in greater signal-to-noise ratios (S/N), S/N of 70 vs. S/N of 5 for corn, as well as fewer non-target peaks in the analysis. Recoveries of aflatoxin using immunoaffinity ranged from 40% to 104.5% (spiked substrate) and 49% to 120% (spiked extract) while percent recoveries of filtered samples ranged from 84% to 119% (spiked substrate) and 88% to 119% (spiked extract). This comparison study showed that filtering is acceptable for small sample sets or where rapid throughput is needed. However, for larger sample sets a more stringent cleanup method is necessary to ensure instrument performance.

免疫亲和层析技术协同酶联免疫吸附法检测赭曲霉毒素A

利用免疫亲和层析技术(immunoaffinity chromatography,IAC)对样品中赭曲霉毒素A(ochratoxin A,OTA)进行捕获与浓缩,利用酶联免疫吸附(enzyme-linked immunosorbent assay,ELISA)法对IAC捕获的目标物OTA进行测定。IAC与ELISA中的抗OTA单克隆抗体来自不同的克隆株,分属不同独特型,与OTA结合靶点的选择性存在差异,IAC与ELISA协同检测,可以有效过滤OTA结构类似物造成的干扰,提高免疫分析的特异性与灵敏度。该方法用于加标样品测定时,OTA的检出限为0.2 ng/g,定量限为0.4 ng/g,OTA的平均回收率为75.9%,与单一的ELISA法相比,该方法虽然回收率略低,但灵敏度可以显著提高,达到ELISA法的60倍。通过对49份样品的实际检测,该方法检出阳性样品与国标法的符合率达到100%,漏检率为0%,由此可见,该方法在准确性上表现出明显的优势。作为一种综合免疫分析技术,该方法不需要大型仪器设备,对操作环境没有严格要求,便于基层实验室对样品中OTA的分析。

基于纳米抗体的可再生免疫亲和柱结合高效液相色谱-串联质谱法测定玉米中的黄曲霉毒素B_(1)

目的研究黄曲霉毒素B_(1)(aflatoxinB_(1),AFB_(1))纳米抗体的表达产量的影响因素,开发具有可再生性的AFB_(1)免疫亲和柱,构建免疫亲和处理-高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)测定玉米中AFB_(1)污染的分析方法。方法研究诱导温度、诱导时间和诱导剂浓度等对AFB_(1)纳米抗体表达量的影响,比对验证AFB_(1)纳米抗体可再生免疫亲和柱的耐受性和可再生使用次数。使用70%甲醇水溶液提取玉米样品中AFB_(1),提取液通过免疫亲和柱净化富集后进行HPLC-MS/MS检测,最后进行方法学验证并应用到实际样品检测。结果诱导AFB_(1)纳米抗体表达的最优条件分别为诱导温度16℃、诱导剂异丙基-β-D-硫代吡喃半乳糖苷浓度0.5 mmol/L、诱导时间14 h,在最优条件下产量可达7.8 mg/L。AFB_(1)纳米抗体具有良好灵敏度、亲和性、特异性和甲醇耐受性,制备的AFB_(1)免疫亲和柱具有极好的可再生性,重复使用150次以上,对AFB_(1)回收率仍可达80%以上。同时,建立的免疫亲和处理-HPLC-MS/MS,在0.1~100.0μg/L范围内呈现良好的线性关系,检出限为0.014μg/L,定量限为0.047μg/L。在3个不同加标浓度下,回收率在92.0%~104.1%,变异系数小于3.9%。结论本研究开发的AFB_(1)纳米抗体免疫亲和柱表现出优秀的再生性和高特异性,节约了检测成本,建立的免疫亲和处理-HPLC-MS/MS检测方法操作简便、回收率高、结果准确,适用于实际玉米样品中AFB_(1)的含量测定。

复合免疫亲和柱净化-超高效液相色谱-串联质谱法测定衢枳壳中5种真菌毒素的含量

提出了题示方法测定衢枳壳样品中黄曲霉毒素B1、B2、G1、G2和赭曲霉毒素A的含量。样品经过体积比79∶20∶1的乙腈-水-乙酸混合溶液超声提取,离心,上清液用p H 7.0磷酸盐缓冲液稀释,用复合免疫亲和柱净化,过滤,滤液中的目标物在XDB C18色谱柱上用不同体积比的体积比1∶9的甲醇-5 mmol·L^(-1)乙酸铵混合溶液和体积比9∶1的甲醇-5 mmol·L^(-1)乙酸铵混合溶液的混合溶液分离,电喷雾离子源正离子(ESI+)和多反应监测(MRM)模式检测,同位素内标法定量。结果显示:5种真菌毒素与其同位素内标质量浓度比和对应的峰面积比在一定范围内呈线性关系,检出限为0.05~0.20μg·kg^(-1)。3个加标浓度水平下阴性样品中5种真菌毒素的回收率为82.7%~97.3%,测定值的相对标准偏差(n=6)为5.2%~12%。

基于壳聚糖微球的黄曲霉毒素B_(1)免疫亲和柱开发制备

目的基于壳聚糖微球制备用于黄曲霉毒素B_(1)检测前处理的免疫亲和柱。方法通过优化化学交联法的反应条件,包括壳聚糖分子量、氨基和醛基摩尔比、壳聚糖浓度和水相油相比,制备粒径大小合适且均一的壳聚糖微球,并以此为载体偶联黄曲霉毒素B_(1)的单克隆抗体制备免疫亲和柱。对亲和柱性能进行分析,使用阳性实际样品对亲和柱使用效果进行验证。结果在最佳制备条件下免疫亲和柱非特异性吸附率为5.26%,对单克隆抗体偶联率为90.90%,柱容量为2.69μg AFB_(1)/mL壳聚糖微球,检测回收率为92.12%~98.62%,相对标准偏差为0.61%~2.53%。用于实际样品检测回收率为87.90%~96.37%。结论本研究建立的免疫亲和柱制备过程简单、成本低,为黄曲霉毒素B_(1)痕量检测前处理提供一种新的方案。

免疫亲和层析高效液相色谱法对小麦粉中脱氧雪腐镰刀菌烯醇的测定

目的:建立测定小麦粉中脱氧雪腐镰刀菌烯醇含量的免疫亲和层析高效液相色谱法。方法:小麦粉经粉碎处理,用水提取,通过免疫亲和柱上样、净化和洗脱后,用高效液相色谱仪测定小麦粉中脱氧雪腐镰刀菌烯醇的含量。结果:在100~5 000 ng·mL^(-1),方法的线性关系良好,相关系数(R^(2))为0.999 8,检出限为48 ng·mL^(-1),回收率为90.1%~109.6%,相对标准偏差为1.49%~2.20%。结论:该方法操作步骤简便,特异性强,精密度高,可以作为大批量分析小麦粉中脱氧雪腐镰刀菌烯醇含量的处理方案。

高效液相色谱法测定薏苡仁中的脱氧雪腐镰刀菌烯醇

目的:构建免疫亲和柱净化与高效液相色谱法相结合以测定薏苡仁中脱氧雪腐镰刀菌烯醇含量的方法。方法:薏苡仁经粉碎处理,用水提取,经免疫亲和柱上样、净化和洗脱后,用高效液相色谱仪测定脱氧雪腐镰刀菌烯醇的含量。结果:在40~400 ng·mL^(-1),脱氧雪腐镰刀菌烯醇的浓度与峰面积呈良好的线性关系,相关系数为1,检出限为9.6μg·kg^(-1),定量限为28.8μg·kg^(-1),回收率为90.7%~106.2%,相对标准偏差均小于4%。结论:该方法操作步骤简便,专属性强,精密度高,可以作为测定薏苡仁中脱氧雪腐镰刀菌烯醇含量的方法。

基于HPLC研究柏子仁中黄曲霉毒素的污染状况与风险分析

目的基于HPLC研究柏子仁中4种黄曲霉毒素的污染情况,并进行风险分析,评估柏子仁的用药安全。方法采用Agilent Eclipse Plus C 18(4.6×250 mm 5μm)为色谱柱,柱后光化学衍生法检测,以甲醇∶乙腈∶水(35∶10∶55)为流动相,流速1.0 mL·min^(-1);柱温:40℃;荧光检测器检测。结果黄曲霉毒素B 1、B 2、G 1、G 2分别在0.35~20.8μg·L^(-1)、0.13~7.6μg·L^(-1)、0.36~21.6μg·L^(-1)、0.13~7.6μg·L^(-1)范围内呈良好的线性关系,黄曲霉毒素B 1、B 2、G 1、G 2平均回收率分别为90.6%、83.46%、87.84%、86.58%,相对偏差分别为2.9%、3.6%、3.6%、4.7%。23批柏子仁中有14批检出黄曲霉毒素B 1和总量,残留量分别在1~4μg·kg^(-1)和1~5μg·kg^(-1)之间,均符合规定,但检出率高达61%,存在安全隐患。结论该方法简单、准确、方便,能有效评价柏子仁中黄曲霉毒素的污染情况。警示柏子仁易受黄曲霉毒素的污染,需加强柏子仁监管力度和不定期的专项抽检,降低安全风险,以确保临床用药安全。

粮食中玉米赤霉烯酮含量测定的前处理方法优化

优化GB 5009.209—2016高效液相色谱法前处理过程,建立新的粮食中玉米赤霉烯酮含量的高效液相色谱测定方法。样品经乙腈-水(V_(乙腈):V_(水)=4∶1)调速振荡器提取,免疫亲和柱富集净化,甲醇洗脱后,直接用水稀释定量至2.00 mL,采用C_(18)反相色谱柱(150 mm×4.6 mm,5.0μm),在10~500 ng/mL的质量浓度范围内线性关系良好,其相关系数R^(2)为0.999,检出限(LOD)和定量限(LOQ)分别为3.8μg/kg、12.8μg/kg,3个浓度水平加标回收率为94.3%~106.3%,精密度为0.8%~6.1%,连续4天的基质加标回收率为96.7%~104.8%,日间精密度为0.8%~4.3%,高效液相色谱可以很好地对粮食中玉米赤霉烯酮进行快速准确定量分析。经验证该方法与国标方法检测结果无显著性差异。与国标相比,尤其是本方法通过去除氮吹、省去流动相复溶步骤可实现快速、简便、批量检测,提高了工作效率。

HPLC 法测定中药中黄曲霉毒素 B1、B2、G1、G2 的含量

目的:建立中药中的黄曲霉毒素 B1、B2、G1、G2的 HPLC 测定方法。方法:样品经有机溶剂提取、免疫亲和柱净化后,用高效液相色谱-柱后衍生-荧光检测器进行分析测定。结果:黄曲霉毒素 G2、B2在2.25-150pg 范围内线性关系良好,黄曲霉毒素 G1、B1在7.5-500pg 范围内线性关系良好,r>0.9999。回收率在60%-110%之间。结论:该方法快速简便,准确,可作为中药中黄曲霉毒素的含量测定方法。

测定玉米中伏马毒素的免疫亲和层析净化高效液相色谱法

伏马毒素(Fumonisins)是串珠镰刀菌繁殖产生的一类真菌毒素。玉米在生长和储存过程中极易受到伏马毒素的侵染。流行病学研究结果表明,受到伏马毒素污染的玉米及其制品可导致马白脑软化症、猪肺水肿综合症,还可诱发人类食管癌和胎儿神经管畸形等疾病。本研究建立了应用免疫亲和柱净化高效液相色谱测定玉米中伏马毒素B1和B2的方法,同时,运用统计学方法对该法进行了准确性和再现性评价。结果表明,FB1和FB2线性范围分别为0.06～5.00μgmL1和0.04～2.50μgmL1,回收率分别为76.6%～93.8%和77.9%～93.4%,FB1和FB2方法定量限分别为0.09mgkg1和0.06mgkg1,实验室内重复性测定的变异系数均低于5%,实验室间再现性测定的变异系数低于6%。上述结果说明该方法的线性、准确度、精密度、灵敏度及同一实验室重复性和多家实验室的再现性评价结果优良,适合作为伏马毒素的测定方法。应用该方法对310份玉米进行了伏马毒素的测定,结果表明,大田、存储玉米伏马毒素总量范围分别为0.20～9.06mgkg1和0.21～6.10mgkg1,建议应加强玉米中伏马毒素污染水平监控,保证人畜健康。

免疫亲和柱HPLC荧光检测酒中黄曲霉毒素B_1、B_2、G_1、G_2

采用单克隆抗体免疫亲和技术作为直接从样品中分离提纯黄曲霉毒素的特效手段 ,提取液挥发干后 ,经衍生用 HPLC荧光检测器测定。本法在样品中添加 2 .5μg/ kg黄曲霉毒素时进行 10次测定 ,平均回收率分别为 G173.8%、B197.3%、G2 6 1.7%、B2 90 .5% ;2 .5μg / kg 10次测定的精密度分别为 :G14.50 %、B13.80 %、G2 3.6 8%、B2 4 .77% ,本方法在 2 5— 12 50 pg范围内呈线性 ,相关系数分别为 G1:r=0 .9990、B1:r=0 .9994、G2 :r=0 .9995、B2 :r=0 .9992。测定的最低检出限为 6 .2

高效液相色谱法测定动物组织样品中黄曲霉毒素的残留量

采用免疫亲合技术,对动物肝脏和肌肉中黄曲霉毒素残留进行了提取和纯化处理,建立了一种快速、灵敏、简便的测定动物组织中黄曲霉毒素B1、B2、G1、G2的高效液相色谱方法。用反相HPLC分离,柱后光化学衍生,荧光检测器测定黄曲霉毒素含量,保留时间定性,峰面积定量,测定了样品和标准样。结果表明,4种毒素可在10min内完成分离;线性范围为15～1500pg;线性回归系数大于0.9998。用本方法对动物肝脏和肌肉样品进行了加标回收实验,4种黄曲霉毒素的平均回收率为68.71%～83.42%;相对标准偏差为3.51%～7.40%;检出限均达到2.65pg。