首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   80篇
  国内免费   1篇
  完全免费   7篇
  化学   88篇
  2019年   1篇
  2018年   1篇
  2017年   2篇
  2016年   5篇
  2015年   2篇
  2014年   5篇
  2013年   3篇
  2012年   4篇
  2011年   10篇
  2010年   9篇
  2009年   8篇
  2008年   6篇
  2007年   11篇
  2006年   5篇
  2005年   7篇
  2004年   4篇
  2002年   1篇
  1999年   1篇
  1996年   1篇
  1990年   1篇
  1978年   1篇
排序方式: 共有88条查询结果,搜索用时 31 毫秒
1.
固相萃取-高效液相色谱检测葡萄酒中赭曲霉毒素A   总被引:7,自引:0,他引:7  
使用C18小柱固相萃取, C18反相柱(250 mm×4.6 mm i.d.)分离,V(乙腈):V(水):V(乙酸)=99:99:2为流动相,荧光检测器(激发波长333 nm,发射波长460 nm)检测,测定葡萄酒中赭曲霉毒素A.其质量浓度在6.25~200 ng/mL范围内呈良好线性,相关系数为0.9997.样品经浓缩60倍后,方法检出限为0.027 ng/mL.对红葡萄酒、干红及白葡萄酒进行了加标回收实验,回收率为80.1%~109.8%.平行7份样品加标回收率相对标准偏差为5.9%.对市售6种葡萄酒进行了赭曲霉毒素A的测定.  相似文献
2.
Wu X  Hu J  Zhu B  Lu L  Huang X  Pang D 《Journal of chromatography. A》2011,1218(41):7341-7346
A sorbent based on the aptamer for ochratoxin A was immobilized onto magnetic nanospheres (MNS) and used to develop a magnetic solid-phase extraction procedure to clean up food samples in conjunction with high-performance liquid chromatography separation and fluorescence detection. Specific retention of ochratoxin A by the sorbent was demonstrated, and the capacity of the MNS-aptamer sorbent was determined. The efficacy of this new approach was successfully evaluated through comparison with solid-phase extraction on commercial C18 cartridge. Several different food samples fortified in the range of with 2.5-50 μg/kg yielded mean recoveries from 67% to 90%, respectively. Finally, this oligosorbent was applied to the selective extraction of ochratoxin A from unfortified food samples.  相似文献
3.
A total of 267 wine samples including 19 dessert, 186 red, 11 rosé and 51 white produced mostly in the years 1997–2002 in Italian and Hungarian regions were analyzed for ochratoxin A (OTA) using inmunoaffinity column (IAC) clean-up and HPLC with fluorimetric detection. None of Hungarian wine samples were contaminated with this mycotoxin. For Italian red wines, 84% of the samples were positive for OTA ranged from 0.01 to 4.00 ng/mL. Furthermore, OTA was detected in 63% of dessert, in 56% of rosé and in 19% of white wine samples ranged from 0.01 to 1.64, from 0.01 to 1.04 and from 0.01 to 0.21 ng/mL, respectively. A study of OTA daily exposure assessment in Italian wines was also carried out outlining a quite low contribution to the overall daily intake.  相似文献
4.
A sensitive and accurate analytical method for the determination of ochratoxin A (OTA) in rice, based on extraction with phosphate-buffered saline/methanol, an immunoaffinity column (IAC) for clean-up, and high performance liquid chromatography with fluorescence detection (HPLC-FD), is described. The limit of quantification of the proposed method was 0.05 g kg–1. Recovery of OTA from rice samples spiked at 0.05 g kg–1 was 92%, with a within-day RSD of 5.4%. The proposed method was applied to 42 rice samples from Portugal and the presence of OTA was found in six samples at concentrations ranging from 0.09 to 3.52 g kg–1. The identification of OTA was confirmed by methyl ester derivatization and then HPLC analysis. The daily intake of OTA by the Portuguese population was also estimated.  相似文献
5.
A molecularly imprinted solid-phase extraction (MISPE) method has been developed for the rapid analysis of wheat extracts for ochratoxin A (OTA). Molecularly imprinted polymer (MIP) particles were synthesized from N-phenylacrylamide (PAM) and slurry-packed into a micro-column for selective solid-phase extraction (SPE) of OTA. With water flowing at 0.5 mL min–1, a total binding capacity of 30 ng OTA was determined for the 20 mg of MIP particles. MISPE conditions were optimized using OTA in methanol/acetic acid (99:1 v/v). Nearly 100% binding could be achieved from one 20-L injection of sample containing up to 30 ng of OTA. Pulsed elution (PE) using methanol/triethylamine (99:1 v/v) was good for the quantitative desorption of OTA. The MISPE–PE method, with fluorescence detection at ex=385 nm and em=445 nm, afforded a detection limit of 5.0 ng mL–1 (or 0.1 ng in 20 L of sample injected) for OTA. Recovery of OTA from wheat extracts was 103±3%. Each MISPE–PE analysis required less than 5 min to complete.  相似文献
6.
A fast, simple, and sensitive HPLC–FD method is described for determination of ochratoxin A (OTA) in pig kidney and muscle; a small mass (<2.5 g) of sample and a relatively small volume (<15 mL) of a non-halogenated extraction solvent are required. Ochratoxin B, systematically absent from all the samples investigated, was used as internal standard. Liquid–liquid partition was used for sample clean-up. Recoveries at the 1 ng g–1 level were 86±15% and 74±8% for kidney and muscle, respectively, and detection limits were 0.14 and 0.15 ng g–1. Clean-up by solid-phase extraction (SPE) is required for pig liver. A survey of the OTA content of tissues of pigs slaughtered in southern Italy revealed that 52 out of 54 analysed samples were contaminated; the OTA concentration in kidney ranged between 0.26 and 3.05 ng g–1. The effect of measurement precision on compliance with legal limits is also discussed.  相似文献
7.
Summary A previously published [1] liquid chromatographic method for the determination of ochratoxin A in corn, barley and kidney has been modified for application to parboiled rice with quantification by high performance thin layer chromatography (HPTLC). The method has been validated by spiking uncontaminated extracts of rice with ochratoxin A over the range 0 to 198 g kg–1. The proposed method has some significant advantages over the current AOAC method [2], especially for determining low levels of ochratoxin A in parboiled rice.  相似文献
8.
以驴抗鼠二抗包被微孔板,以捕获方式包被抗赭曲霉毒素A(OTA)单克隆抗体,利用噬菌体随机七肽库筛选OTA模拟抗原表位,并以其替代检测抗原,建立了基于噬菌体展示技术的酶联免疫吸附分析(Phage ELISA)检测OTA的方法.结果表明,筛选获得的模拟OTA抗原表位七肽氨基酸序列为GMSWMMA.基于模拟表位噬菌体建立的Phage ELISA方法半数抑制浓度(IC50值)为(0.15±0.02) ng/mL,检测OTA的线性范围为0.03~ 0.50 ng/mL,OTA的检出限为0.03 ng/mL,且Phage ELISA与其它4种常见真菌毒素(黄曲霉毒素B1、伏马毒素B1、脱氧雪腐镰刀菌烯醇及玉米赤霉烯酮)无交叉反应.大米样品OTA加标实验表明,批内加标回收率为97.0% ~ 115.2%,批间加标回收率为107.2% ~ 123.1%,与ELISA试剂盒检测结果比较,无显著性差异.  相似文献
9.
核酸适配体识别-荧光法检测赭曲霉素A   总被引:1,自引:0,他引:1  
段诺  吴世嘉  王周平 《分析化学》2011,39(3):300-304
建立了核酸适配体识别-荧光探针技术检测赭曲霉素A(OTA)的新方法。基于微孔板上固定的核酸适配子与目标物质OTA结合时构象发生变化,导致预先与其互补杂交的FAM标记短链DNA解离,引起荧光信号发生变化,据此可实现对OTA的定量检测。当微孔板包被亲和素浓度为25 mg/L、适配子浓度为50 nmol/L,FAM标记互补短链DNA用量为150 nmol/L,OTA结合缓冲液为10 mmol/L HEPES(含120mmol/L NaCl、5 mmol/L KCl、20 mmol/L MgCl2、20 mmol/L CaCl2,pH7.0),45℃反应40 min时,可获得方法的最佳分析结果。在最佳实验条件下,对OTA的检测线性范围为2.0×10-8~1.0×10-5g/L;检出限为1×10-8g/L;相对标准偏差为2.6%(1×10-6g/L,n=11)。本方法选择性良好,操作简单,已成功应用于实际样品中OTA的检测。  相似文献
10.
Ochratoxin A survey in Portuguese wine by LC-FD with direct injection   总被引:1,自引:0,他引:1  
A. Pena  F. Cerejo  L.J.G. Silva  C.M. Lino 《Talanta》2010,82(4):1556-1561
Wine and grape juices were identified as one of the most important sources of ochratoxin A (OTA), a mycotoxin with diverse toxic effects that naturally appears in food and foodstuffs all over the world.The aim of this study was to assess the OTA levels in Portuguese wines through the application of a simple and accurate method based on liquid chromatography (LC) with direct injection, followed by fluorescence detection (FD).Randomly selected wine samples were used to evaluate the performance of direct injection as efficient, fast, inexpensive and safe sample preparation method. The proposed method was successfully validated. The limit of quantification (LOQ) was 1.0 μg/L and OTA recoveries from wine samples, spiked at the three fortification levels, were higher than 85.4%, with RSDs lower than 9.6% for both red and white wines. The presence of OTA was confirmed by methyl ester derivatization followed by LC analysis.Data on OTA levels were obtained for 60 Portuguese red and white wine samples. OTA was found in 12 samples, nine (26%) red wine samples and three (12%) white wine samples. Only one red wine sample and one white wine sample presented a contamination level above the LOQ, with 1.23 and 2.4 μg/L, respectively. It should be pointed out that this white wine sample exceeded the EC maximum permitted level of 2.0 μg/L. The safe dose established as 120 ng/kg body weight/week was not exceeded by the weekly intake estimated for the samples contaminated above the LOQ.  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号